Intel 386 - Manual (Page 273)

Intel386™ EX EMBEDDED PROCESSOR USER’S MANUAL
10-30
10.3.4.3 Read-back Command
Use the read-back format of TMRCON (Figure 10-29) to latch the count and/or status of one or
more counters. Latch a counter’s status to check its programmed operating mode, count format,
and read/write selection and to determine whether the latest count written to it has been loaded.
Figure 10-29. Timer Control Register (TMRCON – Read-back Format)
Timer Control (Read-back Format)
TMRCON Expanded Addr:
ISA Addr:
Reset State: F043H
0043H
XXH
7 0
1 1 COUNT# STAT# CNT2 CNT1 CNT0 0
Bit
Number
Bit
Mnemonic
Function
7–6 — Write ones to these bits to select the read-back command.
00, 01, and 10 are not valid options for TMRCON’s read-back format.
5 COUNT# Count Latch:
0 = Clearing this bit latches the count of each selected counter. Use bits
3–1 to select one or more of the counters.
1 = No effect
4 STAT# Status Latch:
0 = Clearing this bit latches the status of each selected counter. Use bits
3–1 to select one or more of the counters.
1 = No effect
3 CNT2 Counter 2 Select:
0 = The actions specified by bits 5 and 4 do not affect counter 2.
1 = The actions specified by bits 5 and 4 affect counter 2.
2 CNT1 Counter 1 Select:
0 = The actions specified by bits 5 and 4 do not affect counter 1.
1 = The actions specified by bits 5 and 4 affect counter 1.
1 CNT0 Counter 0 Select:
0 = The actions specified by bits 5 and 4 do not affect counter 0.
1 = The actions specified by bits 5 and 4 affect counter 0.
0 — Reserved; for compatibility with future devices, write zero to this bit.