Intel 386 User Manual page 631

Intel386™ EX EMBEDDED MICROPROCESSOR USER'S MANUAL
Timer n (Status Format)
TMR n ( n = 0–2)
7
OUTPUT NULCNT
Bit Bit
Number Mnemonic
7 OUTPUT
6 NULCNT
5–4 RW1:0
3–1 M2:0
0 CNTFMT
D-66
RW1 RW0
Output Status:
This bit indicates the current state of the counter's output signal.
0 = OUT n is low
1 = OUT n is high
Count Status:
This bit indicates whether the latest count written to the counter has
been loaded. Some modes require a gate-trigger before the counter
loads new count values.
0 = the latest count written to the counter has been loaded
1 = a count has been written to the counter but has not yet been loaded
Read/Write Select Status:
These bits indicate the counter's programmed read/write selection.
00 = Never occurs
01 = read/write least-significant byte only
10 = read/write most-significant byte only
11 = read/write least-significant byte first, then most-significant byte
Mode Status:
These bits indicate the counter's programmed operating mode.
000 = mode 0
001 = mode 1
X10 = mode 2
X11 = mode 3
100 = mode 4
101 = mode 5
X is a don't care.
Counter Format Status:
This bit indicates the counter's programmed count format.
0 = binary (16 bits)
1 = binary coded decimal (4 decades)
Expanded Addr: F040H, F041H
F042H
ISA Addr: 0040H, 0041H
0042H
Reset State: XXH
M2 M1 M0
Function
0
CNTFMT