PCI-1710/1710HG
Multifunction DAS Card for
PCI Bus
User's manual
Contents
Chapter 1: General Information ............................. 1
1.1 Introduction ............................................................... 2
1.2 Features .................................................................... 3
1.3 Specifications............................................................. 4
1.4 Block Diagram........................................................... 8
Chapter 2: Installation.............................................. 9
2.1 Initial Inspection ....................................................... 10
2.2 Unpacking ............................................................... 10
2.3 Installation Instructions ............................................. 11
Chapter 3: Signal Connections .............................. 13
3.1 Overview................................................................. 15
3.2 I/O Connector ......................................................... 15
3.3 Analog Input Connections ........................................ 19
3.4 Analog Output Connections ..................................... 23
3.5 Trigger Source Connections ..................................... 25
3.6 Field Wiring Considerations...................................... 25
Chapter 4: Register Structure and Format ......... 27
4.1 Overview................................................................. 28
4.2 I/O Port Address Map............................................. 28
4.3 Channel Number and A/D Data ............................... 33
4.4 Software A/D Trigger............................................... 33
4.5 A/D Channel Range Setting ...................................... 34
4.6 MUX Control .......................................................... 37
4.7 Control Register....................................................... 39
4.8 Status Register ......................................................... 40
4.9 Clear Interrupt and FIFO ......................................... 41
4.10 D/A Channel 0 Output ............................................. 42
4.11 D/A Channel 1 Output ............................................. 42
4.12 D/A Reference Control ............................................ 43
4.13 Digital I/O Registers ................................................. 44
4.14 Programmable Timer/Counter Registers .................... 44
Chapter 5: Calibration............................................ 45
5.1 Introduction ............................................................. 46
5.2 VRAssignment ........................................................ 46
5.3 A/D Calibration ....................................................... 47
5.4 D/A Calibration ....................................................... 48
5.5 Self A/D Calibration................................................. 49
Appendix A: 82C54 Counter Chip Functions ...... 51
A.1 The Intel 82C54 ...................................................... 52
A.2 Counter Read/Write and Control Registers ............... 53
A.3 Counter Operating Modes ....................................... 56
A.4 Counter Operations ................................................. 58
1
General Information
1.1 Introduction
The PCI-1710/1710HG is a multifunction DAS card for the PCI bus.
Advanced circuit design brings you higher quality and more func-
tions, including the five most desired measurement and control
functions: 12-bit A/D conversion, D/A conversion, digital input,
digital output, and counter/timer.
PCI-bus Plug and Play
The PCI-1710/1710HG uses a PCI controller to interface the card with
the PCI bus. The controller fully implements the PCI bus specifica-
tion Rev 2.1. All bus relative configurations, such as base address
and interrupt assignment, are automatically controlled by software.
No jumper or DIP switch setting is required for user configuration.
Flexible Inputs Types and Ranges Setting
The PCI-1710/1710HG features an automatic channel/gain scanning
circuit. The circuit, rather than your software, controls multiplexer
switching during sampling. The on-board SRAM stores different gain
values and configuration for each channel. This design lets you
perform multi-channel high-speed sampling (up to 100 kHz) with
different gains for each channel with free combination of single-ended
and differential inputs.
On-board FIFO (First In First Out) Memory
The PCI-1710/1710HG has an on-board FIFO buffer which can store
up to 4K A/D samples. The PCI-1710/1710HG generates an interrupt
when the FIFO is half full. This feature provides continuous high-
speed data transfer and more predictable performance on Windows
systems.
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PCI-1710 /1710HG User's Manual
On-board Programmable Counter
The PCI-1710/1710HG provides a programmable counter for generat-
ing a pacer trigger for the A/D conversion. The counter chip is an
82C54 or equivalent, which includes three 16-bit counters on a 10
MHz clock. One counter is used as an event counter for counting
events coming from the input channels. The other two are cascaded
together to make a 32-bit timer for a pacer trigger.
1.2 Features
• 16 single-ended or 8 differential analog inputs, or a combination
• 12-bit A/D converter, with up to 100 kHz sampling rate
• Programmable gain for each input channel
• Automatic channel/gain scanning
• On-board 4K samples FIFO buffer
• Two 12-bit analog output channels
•
16 digital inputs and 16 digital outputs
• Programmable pacer/counter
Chapter 1 General Information
3
1.3 Specifications
Analog Input:
• Channels: 16 single-ended or 8 differential (software programma-
ble)
• Resolution: 12-bit
• On-board FIFO: 4K samples
• Conversion time: 8 µs
• Input range: (V, software programmable)
PCI-1710
PCI-1710HG
±10, ±5, ±2.5, ±1.25,
±0.625
±10, ±5, ±1, ±0.5, ±0.1, ±0.05,
±0.01, ±0.005
Bipolar
0 ~ 10, 0 ~ 5, 0 ~ 2.5,
0 ~ 1.25
Unipolar
0 ~ 10, 0 ~ 1, 0 ~ 0.1, 0 ~ 0.01
• Maximum Input Overvoltage: ±30 V
• Common Mode Rejection Ratio (CMRR)
PCI-1710
CMRR
PCI-1710HG
Gain
Gain
0.5, 1
10
CMRR
75dB
0.5, 1
75dB
80dB
84dB
84dB
2
4
8
90dB
100
106dB
106dB
1000
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PCI-1710 /1710HG User's Manual
• Maximum data throughput:
PCI-1710: 100 kHz
PCI-1710HG: (variable, depending on PGIA settling time)
PCI-1710HG
Gain
0.5, 1
Speed
100 kHz
35 kHz
7 kHz
5, 10
50, 100
500, 1000
770 Hz
• Accuracy: (depending on gain)
PCI-1710
PCI-1710HG
Accuracy
Gain
Accuracy
Gain
Remark
0.01% of
FSR ±1 LSB
0.01% of
FSR ±1 LSB
0.5, 1
0.5, 1
S.E./D*
0.02% of
FSR ±1 LSB
0.02% of
FSR ±1 LSB
2
4
8
5, 10
S.E./D
0.02% of
FSR ±1 LSB
0.04% of
FSR ±1 LSB
50, 100
D
D
0.04% of
FSR ±1 LSB
0.08% of
FSR ±1 LSB
500, 1000
*S.E. = Single-ended D = Differential
• Linearity error: ±1 LSB
• Input impedance: 1 GΩ
• Trigger mode: Software, on-board programmable pacer or external
Chapter 1 General Information
5
Analog Output:
• Channels: 2
• Resolution: 12-bit
• Relative accuracy: ±1/2 LSB
• Gain error: ±1 LSB
• Maximum update rate: 100 K samples/s
• Slew rate: 10V/µs
• Output range: (software programmable)
With internal reference: 0 ~ +5 V, 0 ~ +10 V
With external reference: 0 ~ +x V @ -x V (-10 ≤ x ≤ 10)
Digital Input:
• Channels: 16
• Input voltage:
Low: 0.4V max.
High: 2.4 V min.
• Input load:
Low: -0.2 mA @ 0.4V
High: 20 µA @ 2.7 V
Digital Output:
• Channels: 16
• Output voltage:
Low: 0.4V max. @ 8.0 mA (sink)
High: 2.4 V min. @ -0.4 mA (source)
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PCI-1710 /1710HG User's Manual
Programmable Timer/Counter
• Counter chip: 82C54 or equivalent
• Counters: 3 channels, 16 bits, 2 channels are permanently
configured as programmable pacers; 1 channel is free
for user application
• Input, gate: TTL/CMOS compatible
• Time base:
Channel 1:10 MHz
Channel 2:Takes input from output of channel 1
Channel 0:Internal 1 MHz or external clock (10 MHz max.)
selected by software.
General:
• I/O Connector: 68-pin SCSI-II female connector
• Power consumption: +5 V @ 850 mA (Typical),
+5 V @ 1.0 A (Max.)
• Dimensions: 175 mm x 107 mm (6.9” x 4.2”)
• Operating temperature: 0 ~ +60 °C (32 ~ 140 °F) ( refer to IEC 68-
2-1, 2 )
• Storage temperature: -20 ~ +70 °C (-4 ~ 158 °F)
• Operating humidity: 5 ~ 95%RH non-condensing ( refer to IEC 68-
2-3 )
• MTBF: over 64,770 hrs @ 25 °C, grounded, fixed environment
Chapter 1 General Information
7
1.4 Block Diagram
Address Decoder
Address Bus
PCI Controller
16-bit Digital Output
Data Bus
INT
16-bit Digital Input
12-bit D/A Output
12-bit D/A Output
A/D
&
D/A Status
Control Logic
0
1
CNT0_CLK
CNT0_OUT
COUNTER
0
CNT0_GATE
10 MHz/10=
MHz
IRQ Control
Logic
1
4K Samples
FIFO
COUNTER
1
10 MHz
OSC
COUNTER
2
PACER_OUT
EXT_TRG
12-bit A/D
Convertor
A/D Trigger
Logic
AI0
AI1
+
Multiplexer
16 S/E
or
PGIA
-
Channel Scan Logic
8
DIFF
Gain Control RAM
AI15
Figure 1-1: PCI-1710/PCI-1710HG block diagram
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PCI-1710 /1710HG User's Manual
2
Installation
2.1 Initial Inspection
Before installing the PCI-1710/1710HG, check the card for visible
damage. We have carefully inspected the card both mechanically and
electrically before shipment. It should be free of marks and in perfect
order upon receipt.
As you unpack the PCI-1710/1710HG, check it for signs of shipping
damage (damaged box, scratches, dents, etc.). If it is damaged or fails
to meet specifications, notify our service department or your local
sales representative immediately. Also, call the carrier immediately and
retain the shipping carton and packing materials for inspection by the
carrier. We will then make arrangements to repair or replace the unit.
2.2 Unpacking
The PCI-1710/1710HG contains components that are sensitive and
vulnerable to static electricity. Discharge any static electricity on your
body to ground by touching the back of the system unit (grounded
metal) before you touch the board.
Remove the PCI-1710/1710HG card from its protective packaging by
grasping the card's rear panel. Handle the card only by its edges to
avoid static discharge which could damage its integrated circuits.
Keep the antistatic package. Whenever you remove the card from the
PC, protect the card by storing it in this package.
You should also avoid contact with materials that hold static electricity
such as plastic, vinyl and styrofoam.
Check the product contents inside the packing. There should be one
card, one CD-ROM, and this manual. Make sure nothing is missing.
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PCI-1751/1710HG User's Manual
2.3 Installation Instructions
The PCI-1710/1710HG can be installed in any PCI slot in the
computer. However, refer to the computer user's manual to avoid any
mistakes and danger before you follow the installation procedure
below:
1. Turn off your computer and any accessories connected to the
computer.
Warning! TURN OFF your computer power supply whenever
you install or remove any card, or connect and
disconnect cables.
2. Disconnect the power cord and any other cables from the back of
the computer.
3. Remove the cover of the computer.
4. Select an empty 5 V PCI slot. Remove the screw that secures the
expansion slot cover to the system unit. Save the screw to secure
the interface card retaining bracket.
5. Carefully grasp the upper edge of the PCI-1710/1710HG. Align the
hole in the retaining bracket with the hole on the expansion slot and
align the gold striped edge connector with the expansion slot socket.
Press the card into the socket gently but firmly. Make sure the card
fits the slot tightly.
6. Secure the PCI-1710/1710HG by screwing the mounting bracket to
the back panel of the computer.
7. Attach any accessories (68-pin cable, wiring terminal, etc.) to the
card.
8. Replace the cover of your computer. Connect the cables you
removed in step 2.
9. Turn the computer power on.
Chapter 2 Installation
11
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PCI-1751/1710HG User's Manual
3
Signal Connections
3.1 Overview
Correct signal connections are one of the most important factors in
ensuring that your application system is sending and receiving data
correctly. A good signal connection can avoid much unnecessary and
costly damage to your valuable PC and other hardware devices. This
chapter will provide some useful information about how to connect
input and output signals to the PCI-1710/1710HG card via the I/O
connector.
3.2 I/O Connector
The I/O connector for the PCI-1710/1710HG card has 68 pins that you
can connect to 68-pin accessories with the PCL-10168 shielded cable.
Note!
The PCL-10168 shielded cable is specially designed
for the PCI-1710/1710HG for reducing noise in the
analog signal lines. Its wires are all twisted pairs,
and the analog lines and digital lines are seperately
shielded, providing minimal cross talk between
signals and the best protection against EMI/EMC
problems.
Pin Assignment
Figure 3-1 shows the pin assignments for the 68-pin I/O connector on
the PCI-1710/1710HG card.
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PCI-1710/1710HG User's Manual
34
33
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
AI0
AI2
AI4
AI6
AI8
AI10
AI12
AI14
68
67
66
65
64
63
62
61
60
59
58
57
56
55
54
53
52
51
50
49
48
47
46
45
44
43
42
41
40
39
38
37
36
35
AI1
AI3
AI5
AI7
AI9
AI11
AI13
AI15
AIGND
DA1_REF
DA1_OUT
AOGND
DI1
DI3
DI5
DI7
DI9
DI11
DI13
DI15
DGND
DO1
DO3
DO5
DO7
DO9
DO11
DO13
DO15
DGND
PACER_OUT
TRG_GATE
EXT_TRG
+5V
AIGND
DA0_REF
DA0_OUT
AOGND
DI0
DI2
DI4
DI6
DI8
DI10
DI12
DI14
DGND
DO0
DO2
DO4
DO6
DO8
DO10
DO12
DO14
DGND
8
7
6
5
4
3
2
1
CNT0_CLK
CNT0_OUT
CNT0_GATE
+12V
Figure 3-1: I/O connector pin assignments for the PCI-1710/1710 HG card
Chapter 3 Signal Connections
15
I/O Connector Signal Descriptions
Signal
Name
Reference Direction
Description
Analog Input Channels 0 through 15. Each
channel pair, AI<i, i+1> (i = 0, 2, 4...14), can be
configured as either two single-ended inputs or
one differential input.
AI<0…15>
AIGND
AIGND
Input
Analog Input Ground. These pins are the
reference points for single-ended
measurements and the bias current return point
for differential measurement. The three ground
references (AIGND, AOGND, and DGND) are
connected together on the PCI-1710/1710HG
card.
-
-
Analog Output Channel 0 External
DA0_ REF
DA1_ REF
AOGND
AOGND
Input
Input
Reference. This is the external reference input
for the analog output channel 0 circuitry.
Analog Output Channel 1 External
Reference. This is the external reference input
for the analog output channel 1circuitry.
Analog Output Channel 0. This pin supplies
the voltage output of analog output channel 0.
DA0 _OUT
DA1 _OUT
AOGND
AOGND
Output
Output
Analog Output Channel 1. This pin supplies
the voltage output of analog output channel 1.
Analog Output Ground. The analog output
voltages are referenced to these nodes. The
three ground references (AIGND, AOGND, and
DGND) are connected together on the PCI-
1710/1710HG card.
AOGND
-
-
16
PCI-1710/1710HG User's Manual
I/O Connector Signal Descriptions (part II)
Signal Name Reference Direction
Description
Digital Input signals
DI<0..15>
DGND
DGND
Input
Digital Output signals
DO<0..15>
Output
Digital Ground. This pin supplies the
reference for the digital signals at the I/O
connector as well as the +5VDC supply. The
three ground references (AIGND, AOGND,
and DGND) are connected together on the
PCI-1710/1710HG card.
DGND
-
-
Counter 0 Clock Input. This pin is the
external clock input of counter 0. The clock
input of counter 0 can be either external (up
to 10 MHz) or internal (100 kHz), as set by
software.
CNT0_ CLK
DGND
Input
Counter 0 Output. This pin is the output of
counter 0. See Appendix A for more detailed
information.
Counter 0 Gate Input. This pin is the gate
control for counter 0. See Appendix A for
more detailed information.
CNT0 _OUT
CNT0 _GATE
DGND
DGND
Output
Input
Chapter 3 Signal Connections
17
I/O Connector Signal Descriptions (part III)
Signal
Name
Reference Direction
Description
Pacer Clock Output - This pin pulses once for
each pacer clock when turned on. If A/D
conversion is in the pacer trigger mode, users
can use this signal as a synchronous signal for
other applications. A low-to-high edge triggers
A/D conversion to start.
PACER
_OUT
DGND
Output
A/D External Trigger Gate - This pin is
external trigger signal input gate control. When
TRG _GATE is connected to +5 V, it will enable
the external trigger signal to input. When TRG
_GATE is connected to DGND, it will disable
the external trigger signal to input.
TRG _GATE
EXT _TRG
DGND
DGND
Input
Input
A/D External Trigger - This pin is external
trigger signal input for the A/D conversion. A
low-to-high edge triggers A/D conversion to
start.
+12 VDC Source - This pin is +12V power
supply.
+12V
+5V
DGND
DGND
Output
Output
+5 VDC Source - This pin is +5 V power
supply.
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PCI-1710/1710HG User's Manual
3.3 Analog Input Connections
The PCI-1710/1710HG card supports either 16 single-ended or 8
differential analog inputs. Input channel configuration is selected by
software. Selection by software is more convenient than selection by
a slide switch on the card. In the past, if you set one single-ended (or
differential) input channel by switch, the other channels also would be
single-ended (or differential). But on the PCI-1710/1710HG card, if you
set one single-ended (or differential) input channel by software, the
other channels will maintain their original configurations.
Single-ended Channel Connections
The single-ended input configuration has only one signal wire for each
channel, and the measured voltage (Vm) is the voltage of the wire
referred to the common ground.
A signal source without a local ground is also called a “floating
source”. It is fairly simple to connect a single-ended channel to a
floating signal source. In this mode, the PCI-1710/1710HG card
provides a reference ground for external floating signal sources.
Figure 3-2 shows a single-ended channel connection between a
floating signal source and an input channel on the PCI-1710/1710HG
card.
Chapter 3 Signal Connections
19
Internal
External
Figure 3-2: Single-ended input channel connection
Differential Channel Connections
The differential input configuration has two signal wires for each
channel, and the differential input responds only to voltage differenc-
es between High and Low inputs. On the PCI-1710/1710HG card, when
all channels are configured to differential input, up to 8 analog
channels are available.
If one side of the signal source is connected to a local ground, the
signal source is ground-referenced. The ground of the signal source
and the ground of the PCI-1710/1710HG will not be at exactly the same
voltage, as they are connected through the ground return of the
equipment and building wiring. The difference between the ground
voltages forms a common-mode voltage (Vcm).
To avoid the ground loop noise effect caused by common-mode
voltages, you can connect the signal ground to the Low input. Figure
3-3 shows a differential channel connection between a ground-
reference signal source and an input channel on the PCI-1710/1710HG
20
PCI-1710/1710HG User's Manual
card. With this connection, the PGIA rejects a common-mode voltage
Vcm between the signal source and the PCI-1710/1710HG ground,
shown as Vcm in Figure 3-3.
Internal
External
Figure 3-3: Differential input channel connection - ground reference signal source
If a floating signal source is connected to the differential input
channel, the signal source may exceed the common-mode signal range
of the PGIA, and the PGIA will be saturated with erroneous voltage-
readings. You must therefore reference the signal source to the
AIGND.
Figure 3-4 shows a differential channel connection between a floating
signal source and an input channel on the PCI-1710/1710HG card. In
this figure, each side of the floating signal source is connected
through a resistor to the AIGND. This connection can reject the
common-mode voltage between the signal source and the PCI-1710/
1710HG card ground.
Chapter 3 Signal Connections
21
Internal
External
r
a
r
b
Figure 3-4: Differential input channel connection - floating signal source
However, this connection has the disadvantage of loading the source
down with the series combination (sum) of the two resistors. For ra
and rb, for example, if the input impedance rs is 1 kΩ, and each of the
two resistors is 100 kΩ, then the resistors load down the signal source
with 200 kΩ (100 kΩ + 100 kΩ), resulting in a –0.5% gain error. The
following gives a simplified representation of the circuit and calculat-
ing process.
22
PCI-1710/1710HG User's Manual
3.4 Analog Output Connections
The PCI-1710/1710HG card provides two D/A output channels,
DA0_OUT and DA1_OUT. Users may use the PCI-1710/1710HG
internally provided precision –5V (-10V) reference to generate 0 to +5 V
(+10 V) D/A output range. Users also may create D/A output range
through external references, DA0_REF and DA1_REF. The maximum
reference input range is +/-10V. Connecting with an external reference
of -7 V will generate 0 to +7 V DA output.
Figure 3-5 shows how to make analog output and external reference
input connections on the PCI-1710/1710HG card.
Internal
External
-5V
DA0_REF
INT_REF
-10V
+
External Reference
for DA signal 0
DA0_OUT
AOGND
DA 0
DA 1
_
Load
Load
DATA BUS
+
_
External Reference
for DA signal 1
DA1_OUT
DA1_REF
INT_REF
I/O Connector
Figure 3-5: Analog output connections
Chapter 3 Signal Connections
23
3.5 Trigger Source Connections
Internal Pacer Trigger Connection
The PCI-1710/1710HG card includes one 82C54 compatible programma-
ble timer/counter chip which provides three 16-bit counters connected
to a 1 MHz clock, designated as Counter 0, Counter 1 and Counter 2.
Counter 0 is an event counter for counting events coming from the
input channels. Counter 1 and Counter 2 are cascaded to create a 32-
bit timer for pacer triggering. A low-to-high edge from the Counter 2
output (PACER_OUT) will trigger anA/D conversion on the PCI-1710/
1710HG card. At the same time, you can also use this signal as a
synchronous signal for other applications.
External Trigger Source Connection
In addition to pacer triggering, the PCI-1710/1710HG card also allows
external triggering for A/D conversions. When a +5 V source is
connected to TRG_GATE, the external trigger function is enabled. A
low-to-high edge coming from EXT_TRG will trigger an A/D conver-
sion on the PCI-1710/1710HG card. When DGND is connected to
TRG_GATE, the external trigger function is disabled.
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PCI-1710/1710HG User's Manual
3.6 Field Wiring Considerations
When you use the PCI-1710/1710HG card to acquire outside data,
environmental noise can seriously affect the accuracy of your mea-
surements if you don’t provide any protection. The following sugges-
tions will be helpful when running signal wires between signal sources
and the PCI-1710/1710HG card.
• Please make sure that you have carefully routed signal cables to the
card. You must separate the cabling from noise sources. Try to keep
video monitors far away from the analog signal cables, because
these are a common noise source in a PCI data acquisition system.
• If you want to reduce common-mode noise, try to use differential
analog input connections.
• If you do not want your signals to be affected when travelling
through areas with high electromagnetic interference or large
magnetic fields, try the following routing techniques: Use
individually shielded, twisted-pair wires to connect analog input
signals to the board, i.e. the signals connected to the High and Low
inputs are twisted together and covered with a shield. Finally,
connect the shield only to one point at the signal source ground.
• Make sure that your signal lines do not travel through conduits,
because these may contain power lines. Also, keep your signals
far from electric motors, breakers or welding equipment, as these
can create magnetic fields.
• Keep a reasonable distance between high-voltage (or high-current)
lines and signal cables connected to the PCI-1710/1710HG card if the
cables run parallel, or route signal cables at right angles to high
voltage/current cables.
• In addition to outside noise, the transmitted signals themselves
can affect the card's performance. We suggest connecting signal
sources to the card using the PCL-10168 shielded cable in order to
avoid this kind of interference
Chapter 3 Signal Connections
25
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PCI-1710/1710HG User's Manual
4
Register Structure
and Format
4.1 Overview
The PCI-1710/1710HG is delivered with an easy-to-use 32-bit DLL
driver for user programming under the Windows 95/NT operating
system. We advise users to program the PCI-1710/1710HG using the
32-bit DLL driver provided by Advantech to avoid the complexity of
low-level programming by register.
The most important consideration in programming the PCI-1710/
1710HG card at a register level is to understand the function of the
card’s registers. The information in the following sections is provided
only for users who would like to do their own low-level programming.
4.2 I/O Port Address Map
The PCI-1710/1710HG card requires 32 consecutive addresses in the
PC’s I/O space. The address of each register is specified as an offset
from the card’s base address. For example, BASE+0 is the card’s base
address and BASE+7 is the base address plus seven bytes.
Table 4-1 shows the function of each register or driver and its address
relative to the card’s base address.
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PCI-1710/1710HG User's Manual
Table 4-1: PCI-1710/1710HG register format (Part 1)
Base
Read
Address
+ decimal
7
6
5
4
3
2
1
0
Channel Number and A/D Data
CH3
AD7
CH2
AD6
CH1
AD5
CH0
AD4
AD11 AD10
AD3 AD2
AD9
AD1
AD8
AD0
1
0
N/A
3
2
N/A
5
4
Status Register
7
6
IRQ
F/F
F/H
F/E
CNT0 ONE/FH IRQEN GATE
EXT PACER SW
N/A
9
8
N/A
N/A
11
10
13
12
Chapter 4 Register Structure and Format
29
Table 4-1: PCI-1710/1710HG register format (Part 2)
Base
Read
Address
+ decimal
7
6
5
4
3
2
1
0
N/A
15
14
Digital Input
17
16
DI15
DI7
DI14
DI6
DI13
DI5
DI12
DI4
DI11
DI3
DI10
DI2
DI9
DI1
DI8
DI0
Counter 0
25
24
D7
D7
D7
D6
D6
D6
D5
D5
D5
D4
D3
D2
D2
D2
D1
D1
D1
D0
D0
D0
Counter 1
27
26
D4
D3
Counter 2
29
28
D4
D3
N/A
31
30
30
PCI-1710/1710HG User's Manual
Table 4-1: PCI-1710/1710HG register format (Part 3)
Base
Write
Address
+ decimal
7
6
5
4
3
2
1
0
Software A/D Trigger
1
0
A/D Channel Range Setting
3
2
S/D
B/U
G2
G1
G0
MUX Control
5
4
Stop channel
Start channel
Control Register
7
6
CNT0 ONE/FH IRQEN GATE
EXT PACER
SW
Clear Interrupt and FIFO
clear FIFO
9
8
clear interrupt
D/A Output Channel 0
11
10
DA11 DA10 DA9
DA3 DA2
D/A Output Channel 1
DA11 DA10 DA9
DA8
DA7
DA7
DA6
DA6
DA5
DA4
DA1 DA0
13
12
DA8
DA5
DA4
DA3
DA2
DA1 DA0
Chapter 4 Register Structure and Format
31
Table 4-1: PCI-1710/1710HG register format (Part 4)
Base
Write
Address
+ decimal
7
6
5
4
3
2
1
0
D/A Reference Control
15
14
DA1_I/E DA1_5/10 DA0_I/E DA0_5/10
Digital Output
DO15 DO14 DO13 DO12 DO11 DO10
17
16
DO9
DO1
DO8
DO0
DO7
DO6
DO5
DO4
DO3
DO2
Counter 0
25
24
D7
D6
D5
D4
D3
D2
D1
D1
D1
D1
D0
D0
D0
D0
Counter 1
27
26
D7
D6
D5
D4
D3
D2
Counter 2
29
28
D7
D6
D5
D4
D3
D2
Counter Control
31
30
D7
D6
D5
D4
D3
D2
32
PCI-1710/1710HG User's Manual
4.3 Channel Number and A/D Data —
BASE+0 and BASE+1
These two bytes, BASE+0 and BASE+1, hold the result of A/D
conversion data. The 12 bits of data from the A/D conversion are
stored in BASE+1 bit 3 to bit 0 and BASE+0 bit 7 to bit 0. BASE+1
bit 7 to bit 4 hold the source A/D channel number.
Table 4-2: Register for channel number and A/D data
Read
Channel Number and A/D Data
Bit #
7
6
5
4
3
2
1
0
BASE+1 CH3 CH2 CH1 CH0 AD11 AD10 AD9 AD8
BASE+0 AD7 AD6 AD5 AD4 AD3 AD2 AD1 AD0
AD11 ~ AD0 Result of A/D Conversion
AD0 is the least significant bit (LSB) of the A/D data, and AD11 is the
most significant bit (MSB).
CH3 ~ CH0 A/D Channel Number
CH3 ~ CH0 hold the number of the A/D channel from which the data
is received. CH3 is the MSB and CH0 is the LSB.
4.4 Software A/D Trigger — BASE+0
You can trigger an A/D conversion by software, the card’s on-board
pacer or an external pulse. Bit 2 to bit 0 of register BASE+6 can
select the trigger source (see page 39 and page 40 for the register
layout of BASE+6 and programming information). If you select
software triggering, a write to the register BASE+0 with any value will
trigger an A/D conversion.
Chapter 4 Register Structure and Format
33
4.5 A/D Channel Range Setting —
BASE+2
Each A/D channel has its own input range, controlled by a range code
stored in the on-board RAM. If you want to change the range code
for a given channel, select the channel as the start channel and the stop
channel in the registers of BASE+4 and BASE+5 (described in the
next section), and then write the range code to BASE+2 bit 0 to bit 2
and bit 4.
Table 4-3: Register for A/D channel range setting
Write
Bit #
A/D channel range setting
7
6
5
4
3
2
1
0
BASE+2
S/D
B/U
G2
G1
G0
S/D Single-ended or Differential
0 means the channel is single-ended, and 1 means it is differential.
B/U Bipolar or Unipolar
0 means the channel is bipolar, and 1 means it is unipolar.
G2 to G0 Gain Code
34
PCI-1710/1710HG User's Manual
The following table lists the gain codes for the PCI-1710:
Table 4-4: Gain codes for the PCI-1710
PCI-1710
Gain Code
Gain
Input Range(V)
B/U
G2
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
G1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
G0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
1
2
-5 to +5
-2.5 to +2.5
-1.25 to +1.25
-0.625 to +0.625
-10 to 10
N/A
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
4
8
0.5
N/A
N/A
1
2
4
8
0 to 10
0 to 5
0 to 2.5
0 to 1.25
N/A
N/A
N/A
N/A
Chapter 4 Register Structure and Format
35
The following lists the gain codes for the PCI-1710HG:
Table 4-5: Gain codes for the PCI-1710HG
PCI-1710HG
Gain Code
Gain
Input Range(V)
B/U
G2
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
G1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
G0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
1
-5 to +5
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
10
-0.5 to +0.5
-0.05 to +0.05
100
1000 -0.005 to +0.005
0.5
5
-10 to +10
-1 to +1
-0.1 to +0.1
-0.01 to +0.01
0 to 10
0 to 1
50
500
1
10
100
1000
0 to 0.1
0 to 0.01
N/A
N/A
N/A
N/A
36
PCI-1710/1710HG User's Manual
4.6 MUX Control—BASE+4 and BASE+5
Table 4.6: The register for multiplexer control
Write
Bit #
MUX Control
7
6
5
4
3
2
1
0
BASE+5
BASE+4
CH3
CL3
CH2
CL2
CH1
CL1
CH0
CL0
CL3 ~ CL0 Start Scan Channel Number
CH3 ~ CH0 Stop Scan Channel Number
BASE+4 bit 3 to bit 0, CL3 ~ CL0, act as a pointer when you program
the A/D channel setting (see previous section). When you set the
MUX start channel to an analog input channel, AIn ( n = 0, 1, 2…15 ),
the gain code, B/U and S/D written to the register of BASE+2, is for
channel n.
Caution! We recommend you set the same start and stop
channel when writing to the register BASE+2.
Otherwise, if the A/D trigger source is on, the
multiplexer will continuously scan between channels
and the range setting may be set to an unexpected
channel. Make sure the A/D trigger source is turned
off to avoid this kind of error.
The write-only registers of BASE +4 and BASE+5 control how the
multiplexers (MUXs) scan. BASE+4 bit 3 to bit 0, CL3 ~ CL0, hold
the start scan channel number, and BASE+5 bit 3 to bit 0, CH3 ~ CH0,
hold the stop scan channel number. Writing to these two registers
automatically initializes the scan range of the MUXs. Each A/D
conversion trigger also sets the MUXs to the next channel. With
continuous triggering, the MUXs will scan from the start channel to
Chapter 4 Register Structure and Format
37
the stop channel and then repeat. The following examples show the
scan sequences of the MUXs (all channels are set as single-ended).
Example 1
If the start scan input channel is AI3 and the stop
scan input channel is AI7, then the scan sequence is AI3, AI4, AI5,
AI6, AI7, AI3, AI4, AI5, AI6, AI7, AI3, AI4…
Example 2
If the start scan channel is AI13 and the stop
scan channel is AI2, then the scan sequence is AI13, AI14, AI15, AI0,
AI1, AI2, AI13, AI14, AI15, AI0, AI1, AI2, AI13, AI14…
The scan logic of the PCI-1710/1710HG card is powerful and easily
understood. You can set the gain code, B/U and S/D, for each channel.
The scan logic will be a little complex if you set the analog input
channels in differential mode, however. In differential mode, signals
are transmitted by a pair of channels, AI<i, i+1> ( i = 0, 2, 4…
14) . In each pair of differential channels, the even channel is the
positive end and the odd one is the negative end.
For example, if channel 0 is set as differential, then channel 0 and
channel 1 are combined into one channel and refer to the gain code
and B/U of channel 0 (the channel 1 values are unavailable). By the
same rule, if channel 2 is set as differential, then channel 2 and channel
3 are combined into one channel, and refer to the gain code and B/U of
channel 2 (the channel 3 values are unavailable). The following
examples show the scan sequences in differential mode.
Example 3
Suppose that the start scan input channel is AI14
and the stop scan input channel is AI3. If AI14 is differential, AI0 and
AI1 are single-ended, and AI2 is differential, then the scan sequence is
AI14, AI0, AI1, AI2, AI14, AI0, AI1, AI2, AI14…..
Example 4
Suppose that the start scan channel is AI11 and
the stop scan channel is AI15. If AI11 is single-ended, AI12 is
38
PCI-1710/1710HG User's Manual
differential, and AI14 is differential, then the scan sequence is AI11,
AI12, AI14, AI11, AI12, AI14, AI11…
Warning! Only even channels can be set as differential. An
odd channel will become unavailable if its preceding
channel is set as differential.
4.7 Control Register — BASE+6
The write-only register BASE+6 allows users to set an A/D trigger
source and an interrupt source.
Table 4-7: Control register
Write
Bit #
Control Register
7
6
5
4
3
2
1
0
BASE + 6
CNT0 ONE/FH IRQEN GATE
EXT PACER SW
SW Software trigger enable bit
Set 1 to enable software trigger, and set 0 to disable.
PACER PACER trigger enable bit
Set 1 to enable pacer trigger, and set 0 to disable.
EXT External trigger enable bit
Set 1 to enable external trigger, and set 0 to disable.
Note!
Users cannot enable SW, PACER and EXT
concurrently.
Chapter 4 Register Structure and Format
39
GATE External trigger gate function enable bit
Set 1 to enable external trigger gate function, and set 0 to disable.
IRQEN Interrupt enable bit
Set 1 to enable interrupt, and set 0 to disable.
ONE/FH Interrupt source bit
Set 0 to interrupt when an A/D conversion occurs, and set 1 to
interrupt when the FIFO is half full.
CNT0 Counter 0 clock source select bit
0 means that the clock source of Counter 0 comes from the internal
clock (100 kHz), and 1 means that the clock source of Counter 0
comes from the external clock (maximum up to 10 MHz).
4.8 Status Register — BASE+6 and
BASE+7
The registers of BASE+6 and BASE+7 provide information for the A/
D configuration and operation.
Table 4-8: Status register
Read
Bit #
Status Register
7
6
5
4
3
2
1
0
BASE+7
BASE+6
IRQ
F/F
F/H
F/E
CNT0 ONE/FH IRQEN GATE
EXT PACER SW
The content of the status register of BASE+6 is the same as that of the
control register.
F/E FIFO Empty flag
This bit indicates whether the FIFO is empty. 1 means that the FIFO is
empty.
40
PCI-1710/1710HG User's Manual
F/H FIFO Half-full flag
This bit indicates whether the FIFO is half-full. 1 means that the FIFO
is half-full.
F/F FIFO Full flag
This bit indicates whether the FIFO is full. 1 means that the FIFO is
full.
IRQ Interrupt flag
This bit indicates the interrupt status. 1 means that an interrupt has
occurred.
4.9 Clear Interrupt and FIFO — BASE+8
and BASE+9
Writing data to either of these two bytes clears the interrupt or the
FIFO.
Table 4-9: Registers to clear interrupt and FIFO
Write
Bit #
Clear Interrupt and FIFO
7
6
5
4
3
2
1
0
BASE+9
BASE+8
Clear FIFO
Clear Interrupt
Chapter 4 Register Structure and Format
41
4.10 D/A Output Channel 0 — BASE+10
and BASE+11
The write-only registers of BASE+10 and BASE+11 accept data for
D/A Channel 0 output.
Table 4-10: Registers for D/A channel 0 data
Write
Bit #
D/A Output Channel
7
6
5
4
3
2
1
0
BASE+11
BASE+10
DA11 DA10
DA3 DA2
DA9
DA1
DA8
DA0
DA7
DA6
DA5
DA4
DA11 ~ DA0 Digital to Analog data
DA0 is the LSB and DA11 is the MSB of the D/A data.
4.11 D/A Output Channel 1 — BASE+12
and BASE+13
The write-only registers of BASE+12 and BASE+13 accept data for
the D/A channel 1 output.
Table 5-11: Registers for D/A channel 1 data
Write
Bit #
D/A Output Channel
7
6
5
4
3
2
1
0
BASE+13
BASE+12
DA11 DA10
DA3 DA2
DA9
DA1
DA8
DA0
DA7
DA6
DA5
DA4
DA11 ~ DA0 Digital to Analog data
DA0 is the LSB and DA11 is the MSB of the D/A data.
42
PCI-1710/1710HG User's Manual
4.12 D/A Reference Control —
BASE+14
The write-only register of BASE+14 allows users to set the D/A
reference source.
Table 4-12: Registers for D/A reference control
Write
Bit #
D/A Reference Control
7
6
5
4
3
2
1
0
BASE+14
DA1_I/E DA1_5/10 DA0_I/E DA0_5/10
DA0_5/10 The internal reference voltage for the D/A output
channel 0
This bit controls the internal reference voltage for the D/A output
channel 0. 0 means that the internal reference voltage is 5 V, and 1
means it is 10 V.
DA0_I/E Internal or external reference voltage for the D/A output
channel 0
This bit indicates that the reference voltage for the D/A output channel
0 is internal or external. 0 means that the reference voltage comes
from the internal source, and 1 means it comes from an external
source.
DA1_5/10 The internal reference voltage for the D/A output
channel 1
This bit controls the internal reference voltage for the D/A output
channel 1. 0 means that the internal reference voltage is 5 V, and 1
means it is 10 V.
DA1_I/E Internal or external reference voltage for the D/A output
channel 1
This bit indicates that the reference voltage for the D/A output channel
1 is internal or external. 0 means that the reference voltage comes
from the internal source, and 1 means it comes from an external
source.
Chapter 4 Register Structure and Format
43
4.13 Digital I/O Registers — BASE+16
and BASE+17
The PCI-1710/1710HG card offers 16 digital input channels and 16
digital output channels. These I/O channels use the input and output
ports at addresses BASE+16 and BASE+17.
Table 4-13: Register for digital input
Read
Bit #
Digital Input
7
6
5
4
3
2
1
0
BASE+17
BASE+16
DI15
DI7
DI14
DI6
DI13
DI5
DI12
DI4
DI11
DI3
DI10
DI2
DI9
DI1
DI8
DI0
Table 4-14: Register for digital output
Write
Digital Output
Bit #
7
6
5
4
3
2
1
0
BASE+17 DO15 DO14 DO13 DO12 DO11 DO10
DO9
DO1
DO8
DO0
BASE+16
DO7
DO6
DO5
DO4
DO3
DO2
Note!
The default configuration of the digital output chan-
nels is a logic 0.This avoids damaging external
devices during system start-up or reset since the
power on status is set to the default value.
4.14 Programmable Timer/Counter
Registers — BASE+24, BASE+26,
BASE+28 and BASE+30
The four registers of BASE+24, BASE+26, BASE+28 and BASE+30
are used for the 82C54 programmable timer/counter. Please refer to
Appendix A data sheets for detailed application information.
Note!
Users have to use a 16-bit (word) command to read/
write each register.
44
PCI-1710/1710HG User's Manual
5
Calibration
5.1 Introduction
Regular calibration checks are important to maintain accuracy in data
acquisition and control applications. We provide two calibration
programs, ADCAL.EXE and DACAL.EXE, on the PCI-1710/1710HG
software CD-ROM. ADCAL.EXE assists you in A/D calibration, and
DACAL.EXE in D/A calibration.
The ADCAL.EXE and DACAL.EXE make calibrations easy. It leads
you through the calibration and setup procedure with a variety of
prompts and graphic displays, showing you all of the correct settings
and adjustments. This appendix offers a brief guide to these
calibration programs.
To perform a satisfactory calibration, you need a 41/2-digit digital
multimeter and a voltage calibrator or a stable, noise free D. C. voltage
source.
5.2 VR Assignment
There are five variable resistors (VRs) on the PCL-1710/1710HG
card. They help you to make accurate adjustments on all A/D and D/A
channels. Please refer to the following figure for VR position.
VR 4
VR 5
VR 1
VR 2
VR 3
P1
Figure 5-1: PCL-1710/1710HG VR assignment
46
PCI-1710/1710HG User's Manual
The following list shows the function of each VR:
VR
Function
VR1
A/D unipolar offset
VR2
VR3
VR4
VR5
A/D bipolar offset
A/D full scale (gain)
D/A channel 0 full scale
D/A channel 1 full scale
5.3 A/D Calibration
Regular and accurate calibration procedures ensure the maximum
possible accuracy. The ADCAL.EXE calibration program leads you
through the whole A/D offset and gain adjustment procedure. The
basic steps are outlined below:
1. Set analog input channel AI0 as single-ended, bipolar, range ±5 V,
and set AI1 as single-ended, unipolar, range 0 to 10 V.
2. Connect a DC voltage source with value equal to 0.5 LSB
(-4.9959 V) to AI0.
3. Adjust VR2 until the output codes from the card's AI0 flickers
between 0 and 1.
4. Connect a DC voltage source with a value of 4094.5 LSB (4.9953
V) to AI0.
5. Adjust VR3 until the output codes from the card's AI0 flickers
between 4094 and 4095.
6. Repeat step 2 to step 5, adjusting VR2 and VR3.
7. Connect a DC voltage source with value equal to 0.5 LSB (1.22
mV) to AI1.
8. Adjust VR1 until the output codes from the card's AI1 flickers
between 0 and 1.
Chapter 5 Calibration 47
A/D code
Mapping Voltage
Hex.
Dec.
0
Bipolar ± 5V
Unipolar 0 to 10V
0V
000h
7FFh
800h
FFFh
-4.9971V
-0.0024V
0V
2047
2048
4095
4.9947V
4.9971V
+4.9947V
9.9918V
5.4 D/A Calibration
In a way similar to the ADCAL.EXE program, the DACAL.EXE
program leads you through the whole D/A calibration procedure.
You can either use the on-board -5 V (-10 V) internal reference
voltage or use an external reference. If you use an external reference,
connect a reference voltage within the range ±10 V to the reference
input of the D/A output channel you want to calibrate. Adjust the full
scale (gain) of D/A channel 0 and 1, with VR4 and VR5 respectively.
Note!
Using a precision voltmeter to calibrate the D/A
outputs is recommended.
Set the D/A data register to 4095 and adjust VR3 until the D/A output
voltage equals the reference voltage minus 1 LSB, but with the
opposite sign. For example, if Vref is -5 V, then Vout should be +4.9959
V. If Vref is -10 V, Vout should be +9.9918 V.
48
PCI-1710/1710HG User's Manual
5.5 Self A/D Calibration
Under many conditions, it is difficult to find a good enough DC
voltage source for A/D calibration. There is a simple method to solve
this problem. First, you should calibrate D/A channel 0, DA0_OUT,
with internal reference -5 V, and D/A channel 1, DA1_OUT, with
reference -10 V.
Then, run the ADCAL.EXE program to finish the self-A/D calibration
procedure.
1. Set AI0 as differential, bipolar, range ±5 V and AI2 as differential,
unipolar, range 0 to 10 V.
2. Connect DA0_OUT with codes equal to 4095 LSB (4.9959 V) to
AI 0. Notice that the polarity of AI0 should be connected with
reverse polarity (i.e. D/A + to A/D -, D/A - to A/D +).
3. Adjust VR2 until the output codes from the card's AI0 flicker
between 0 and 1.
4. Connect DA0_OUT with codes equal to 4095 LSB (4.9959 V) to
AI0.
5. Adjust VR3 until the output codes from the card's AI0 flickers
between 4094 and 4095.
6. Repeat steps 2 through 5, adjusting VR2 and VR3.
7. Connect DA1_OUT with codes equal to 1 LSB (2.44 mV) to AI2.
8. Adjust VR1 until the output codes from the card's AI1 flicker
between 0 and 1.
9. Finish ADCAL.EXE.
Chapter 5 Calibration 49
50
PCI-1710/1710HG User's Manual
A
82C54 Counter Chip
Functions
A.1 The Intel 82C54
The PCI-1710/1710HG uses one Intel 82C54 compatible programma-
ble interval timer/counter chip. The popular 82C54 offers three
independent 16-bit counters, counter 0, counter 1 and counter 2. Each
counter has a clock input, control gate and an output. You can
program each counter for maximum count values from 2 to 65535.
The 82C54 has a maximum input clock frequency of 1 MHz. The
PCI-1710/1710HG provides 1 MHz input frequencies to the counter
chip from an on-board crystal oscillator.
Counter 0
On the PCI-1710/1710HG, counter 0 can be a 16-bit timer or an event
counter, selectable by users. When the clock source is set as an
internal source, counter 0 is a 16-bit timer; when set as an external
source, then counter 0 is an event counter and the clock source comes
from CNT0_CLK. The counter is controlled by CNT0_GATE. When
CNT0_GATE input is high, counter 0 will begin to count.
Counter 1 & 2
Counter 1 and counter 2 of the counter chip are cascaded to create a
32-bit timer for the pacer trigger. A low-to-high edge of counter 2
output (PACER_OUT) will trigger an A/D conversion. At the same
time, you can use this signal as a synchronous signal for other
applications.
52
PCI-1750 User's Manual
A.2 Counter Read/Write and
Control Registers
The 82C54 programmable interval timer uses four registers at
addresses BASE + 24(Dec), BASE + 26(Dec), BASE + 28(Dec) and
BASE + 30(Dec) for read, write and control of counter functions.
Register functions appear below:
Register
Function
BASE + 24(Dec) Counter 0 read/write
BASE + 26(Dec) Counter 1 read/write
BASE + 28(Dec) Counter 2 read/write
BASE + 30(Dec) Counter control word
Since the 82C54 counter uses a 16-bit structure, each section of
read/write data is split into a least significant byte (LSB) and most
significant byte (MSB). To avoid errors it is important that you make
read/write operations in pairs and keep track of the byte order.
The data format for the control register appears below:
BASE+30(Dec) 82C54 control, standard mode
Bit
D7
D6
D5
D4
D3
D2
D1
D0
Value
SC1 SC0 RW1 RW0 M2
M1
M0
BCD
Description:
SC1 & SC0 Select counter.
Counter
0
1
SC1
0
SC0
0
0
1
2
1
1
0
1
Read-back command
Appendix A 8524 Counter Chip Functions 53
RW1 & RW0
Select read/write operation
Operation
RW1
RW0
Counter latch
0
0
Read/write LSB
Read/write MSB
0
1
1
1
0
1
Read/write LSB first,
then MSB
M2, M1 & M0
Select operating mode
M2
M1
M0
Mode
Description
0
0
0
1
1
0
0
0
0
Stop on terminal count
0
X
X
1
1
1
0
1
0
1
1
2
3
4
5
Programmable one shot
Rate generator
Square wave rate generator
Software triggered strobe
Hardware triggered strobe
BCD
Select binary or BCD counting.
BCD Type
0
1
Binary counting 16-bits
Binary coded decimal (BCD) counting
If you set the module for binary counting, the count can be any
number from 0 up to 65535. If you set it for BCD (Binary Coded
Decimal) counting, the count can be any number from 0 to 9999.
If you set both SC1 and SC0 bits to 1, the counter control register is in
read-back command mode. The control register data format then
54
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becomes:
BASE + 30(Dec) 82C54 control, read-back mode
Bit
D7
1
D6
1
D5
D4
D3
D2
C1
D1
C0
D0
X
Value
CNT STA C2
CNT = 0
STA = 0
Latch count of selected counter(s).
Latch status of selected counter(s).
C2, C1 & C0 Select counter for a read-back operation.
C2 = 1 select Counter 2
C1 = 1 select Counter 1
C0 = 1 select Counter 0
If you set both SC1 and SC0 to 1 and STA to 0, the register selected
by C2 to C0 contains a byte which shows the status of the counter.
The data format of the counter read/write register then becomes:
BASE+24/26/28(Dec) Status read-back mode
Bit
D7
D6
D5
D4
D3
D2
D1
D0
Value
OUT NC
RW1 RW0 M2
M1
M0
BCD
OUT
NC
Current state of counter output
Null count is 1 when the last count written to the counter
register has been loaded into the counting element
Appendix A 8524 Counter Chip Functions 55
A.3 Counter Operating Modes
MODE 0 – Stop on Terminal Count
The output will initially be low after you set this mode of operation.
After you load the count into the selected count register, the output
will remain low and the counter will count. When the counter reaches
the terminal count, its output will go high and remain high until you
reload it with the mode or a new count value. The counter continues
to decrement after it reaches the terminal count. Rewriting a counter
register during counting has the following results:
1. Writing to the first byte stops the current counting.
2. Writing to the second byte starts the new count.
MODE 1 – Programmable One-shot Pulse
The output is initially high. The output will go low on the count
following the rising edge of the gate input. It will then go high on the
terminal count. If you load a new count value while the output is low,
the new value will not affect the duration of the one-shot pulse until
the succeeding trigger. You can read the current count at any time
without affecting the one-shot pulse. The one-shot is retriggerable,
thus the output will remain low for the full count after any rising edge
at the gate input.
MODE 2 – Rate Generator
The output will be low for one period of the input clock. The period
from one output pulse to the next equals the number of input counts in
the counter register. If you reload the counter register between output
pulses, the present period will not be affected, but the subsequent
period will reflect the value.
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The gate input, when low, will force the output high. When the gate
input goes high, the counter will start from the initial count. You can
thus use the gate input to synchronize the counter.
With this mode the output will remain high until you load the count
register. You can also synchronize the output by software.
MODE 3 – Square Wave Generator
This mode is similar to Mode 2, except that the output will remain
high until one half of the count has been completed (for even num-
bers), and will go low for the other half of the count. This is accom-
plished by decreasing the counter by two on the falling edge of each
clock pulse. When the counter reaches the terminal count, the state of
the output is changed, the counter is reloaded with the full count and
the whole process is repeated.
If the count is odd and the output is high, the first clock pulse (after
the count is loaded ) decrements the count by 1. Subsequent clock
pulses decrement the count by 2. After time-out, the output goes low
and the full count is reloaded. The first clock pulse (following the
reload) decrements the counter by 3. Subsequent clock pulses decre-
ment the count by two until time-out, then the whole process is
repeated. In this way, if the count is odd, the output will be high for
(N+1)/2 counts and low for (N-1)/2 counts.
MODE 4 –Software-Triggered Strobe
After the mode is set, the output will be high. When the count is
loaded, the counter will begin counting. On terminal count, the output
will go low for one input clock period then go high again.
If you reload the count register during counting, the new count will be
loaded on the next CLK pulse. The count will be inhibited while the
GATE input is low.
MODE 5 – Hardware-Triggered Strobe
The counter will start counting after the rising edge of the trigger
input and will go low for one clock period when the terminal count is
reached. The counter is retriggerable.
Appendix A 8524 Counter Chip Functions 57
A.4 Counter Operations
Read/Write Operation
Before you write the initial count to each counter, you must first
specify the read/write operation type, operating mode and counter
type in the control byte and write the control byte to the control
register [BASE + 30(Dec)].
Since the control byte register and all three counter read/write
registers have separate addresses and each control byte specifies the
counter it applies to (by SC1 and SC0), no instructions on the operat-
ing sequence are required. Any programming sequence following the
82C54 convention is acceptable.
There are three types of counter operation: Read/load LSB, read /load
MSB and read /load LSB followed by MSB. It is important that you
make your read/write operations in pairs and keep track of the byte
order.
Counter Read-back Command
The 82C54 counter read-back command lets you check the count
value, programmed mode and current states of the OUT pin and Null
Count flag of the selected counter(s). You write this command to the
control word register. Format is as shown at the beginning of this
section.
The read-back command can latch multiple counter output latches.
Simply set the CNT bit to 0 and select the desired counter(s). This
single command is functionally equivalent to multiple counter latch
commands, one for each counter latched.
The read-back command can also latch status information for selected
counter(s) by setting STA bit = 0. The status must be latched to be
read; the status of a counter is accessed by a read from that counter.
The counter status format appears at the beginning of the chapter.
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Counter Latch Operation
Users often want to read the value of a counter without disturbing the
count in progress. You do this by latching the count value for the
specific counter then reading the value.
The 82C54 supports the counter latch operation in two ways. The first
way is to set bits RW1 and RW0 to 0. This latches the count of the
selected counter in a 16-bit hold register. The second way is to
perform a latch operation under the read-back command. Set bits SC1
and SC0 to 1 and CNT = 0. The second method has the advantage of
operating several counters at the same time. A subsequent read
operation on the selected counter will retrieve the latched value.
Appendix A 8524 Counter Chip Functions 59
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