2192-09066-000-000
Counter Timers
The PCIB40 includes three programmable 16-bit counter/timers. Counter 0 may be driven by either
a 10KHz, 100KHz or 1MHz clock and can be used to generate regular interrupts. An interrupt is
generated only when the counter 0 output goes to a ‘1’.
The input and gate control signals of counters 1 and 2 are connected as inputs from the D-50 while
the counter outputs are linkable to the D-50 connector. Counter inputs 1 and 2 may be used for
frequency or pulse measurement and the outputs used for pulse generation. Refer to the link
section and pin assignments table for connection details.
I/O map
The value written to the pointer register is used to select the on-board I/O location to be accessed.
This board occupies two consecutive addresses and has nine I/O function registers and three
special function registers.
The board must be set on an even address boundary. (i.e. 180h, 182h, 200h etc.)
I/O Function Registers
* A copy of the 8254 (71054) data sheet may be obtained from our Customer Support team (Tel: 01223 412 428)
J206 PCIB40 Technical Manual
5
Address
Base (180h)
Write Only
Pointer Register
On-board register
(e.g. 80h)
Base+1 (181H)
Read/Write
Data Register
Data to Read/Write
from/to register
Read/write
Register Name
Register Function
Pointer Value
(hex)
00
Write
Read
Write
Read
Write
Read
Write
Read
Write
Read
Read/Write
Read/Write
Read/Write
Write
Output Control Latches Group 0
Bit 0-7
0= Output ‘0’
1= Output ‘1’
0= Input ‘0’
1= Input ‘1’
0= Output ‘0’
1= Output ‘1’
0= Input ‘0’
1= Input ‘1’
0= Output ‘0’
1= Output ‘1’
0= Input ‘0’
1= Input ‘1’
0= Output ‘0’
1= Output ‘1’
0= Input ‘0’
1= Input ‘1’
0= Output ‘0’
1= Output ‘1’
0= Input ‘0’
1= Input ‘1’
See data sheet 8254*
See data sheet 8254*
See data sheet 8254*
See data sheet 8254*
Bit 0-7
Bit 0-7
Bit 0-7
Bit 0-7
Bit 0-7
Bit 0-7
Bit 0-7
Bit 0-7
Bit 0-7
Bit 0-7
Bit 0-7
Bit 0-7
Bit 0-7
Status of Group 0
Output Control Latches Group 1
Status of Group 1
Output Control Latches Group 2
Status of Group 2
Output Control Latches Group 3
Status of Group 3
Output Control Latches Group 4
Status of Group 4
Not Used
Counter/timer 0 Access
Counter/timer 1 Access
Counter/timer 2 Access
Counter/Timer Control Word
00
01
01
02
02
03
03
04
04
05 - 0F
10
11
12
13
Read/Write
Pointer Name
Pointer Bit
Functions
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