5. Counter/Timers
43
Control Register
The Control register is used to initialize the counter/timers and to select the method of
reading the count and status information. The Control register is best described by
dividing it into three formats as illustrated below.
7
6
5
4
3
2
1
0
Register: General Control
Address: 43h
Count Format
BCD
Access: Write
Access
0 Binary
Select
Mode
1 BCD
Operating Mode
000 Terminal count interrupt
001 Retriggerable one-shot
010 Rate generator
011 Square wave generator
100 Software strobe
101 Hardware strobe
110 Same as "010"
111 Same as "011"
Access Mode
00 Count latch command
01 Low byte only
10 High byte only
11 Low byte followed by high byte
Select Counter
00 Counter 0
01 Counter 1
10 Counter 2
11 Read back
General Control Register
Counter
0
7
6
5
4
3
2
1
0
Register: Count Latch Control
Address: 43h
Counter Latched
Access: Write
00 Counter 0
0
0
0
0
0
01 Counter 1
10 Counter 2
11 Read back
Count Latch Control Register