DM5210 analog input module 4-6 RTD Embedded Technologies, Inc.
For example, if you want to set Port C bit 0 to 1, you would set up the control word so that bit 7 is 0; bits 1, 2,
and 3 are 0 (this selects PC0); and bit 0 is 1 (this sets PC0 to 1). The control word is set up like this:
D7
D6
D5
D4
D3
D2
D1
D0
Set/Reset
Function Bit
Bit Select
000 = PC0
Set PC0
X = don’t care
Sets PC0 to 1:
(written to BA +3)
0
X
X
X
0
0
0
1
BA + 4: 8254 Timer/Counter 0 (Read/Write)
A read shows the count in the counter, and a write loads the counter with a new value. Counting begins as soon
as the count is loaded.
BA + 5: 8254 Timer/Counter 1 (Read/Write)
A read shows the count in the counter, and a write loads the counter with a new value. Counting begins as soon
as the count is loaded.
BA + 6: 8254 Timer/Counter 2 (Read/Write)
A read shows the count in the counter, and a write loads the counter with a new value. Counting begins as soon
as the count is loaded.
BA + 7: 8254 Control Word (Write Only)
Accesses the 8254 control register to directly control the three timer/counters.
D7
D6
D5
D4
D3
D2
D1
D0
Counter Select
00 = Counter 0
01 = Counter 1
10 = Counter 2
11 = read back setting
BCD/Binary
0 = binary
1 = BCD
Counter Mode Select
000 = Mode 0, event count
001 = Mode 1, programmable 1-shot
010 = Mode 2, rate generator
011 = Mode 3, square wave rate generator
100 = Mode 4, software-triggered strobe
101 = Mode 5, hardware-triggered strobe
Read/Load
00 = latching operation
01 = read/load LSB only
10 = read/load MSB only
11 = read/load LSB, then MSB
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
