Instruction manual

Page
35
PC215E
Command Word for Mode Definition Format
Command Word for Bit Set/Reset Format
5.3.9 Z1 Counter 0 Data Register
The 82C54 Programmable Timer Counter Z1 provides three 16 bit counter/timers which can be
independently programmed to operate in any one of six modes with BCD or Binary count
functions. The register definition for Z1 Counter 0 Data is as follows.
Register
Offset
Write and/or
Read
Register
Width
Register
Title
Mnemonic
10
16
Write and Read 8 bits
82C54 Counter/Timer Z1
Counter 0 Data Register
Z1 CT0
01234567
Port C (Lower) 0 = Output
1 = Input
Port B 0 = Output
1 = Input
Mode Selection 0 = Mode 0
1 = Mode 1
GROUP B
Port C (Upper) 0 = Output
1 = Input
Port A 0 = Output
1 = Input
Mode Selection 00 = Mode 0
01 = Mode 1
1X = Mode 2
GROUP A
e
Set Flag 1 = Active
COMMAND
SELECT
01234567
Bit Set/Reset 0 = Reset
1 = Set
Port C Bit Select
Bit Set/Reset Flag
0 = Active
COMMAND
SELECT
6 74 5
2 3
0 1
0 B
0
10 1
0 1
0 1
1 B
1
10 01 10 0
1 B
2
11 10 00 0
X X X
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