Intel MCS 51 User Manual

intel.
MCS@-51PROGRAMMER’SGUIDE AND INSTRUCTIONSET
TIMER SET-UP
Tables3 through6 givesomevaluesfor TMODwhicheen be usedto setup TimerOin differentmodes.
It is assumedthat onlyonetimer isbeingusedat a time.If it isdesiredto run TimersOend 1simukaneoudy,in
snY
mod%
the valuein TMOD for Timer Omust be ORedwith the valueshownfor Timer 1(Tables5 and 6).
For example,ifit isdesiredto run TimerOin mode1GATE (externalcontrol),andTimer 1in mode2 COUNTER,
then the valuethat must be loadedinto TMODis 69H(09Hfrom Table3 ORedwith 60HfromTable6).
Moreover.it is assumedthat the user,at this mint, isnot readyto turn the timersonand willdo that at a different
pointin he programby settingbit T-Rx(in TCON)to 1. -
TIMER/COUNTER O
As a Timer:
Table 3
MODE
o
1
2
3
““Nm
13-bitTimer
OOH
08H
16-bitTimer OIH
09H
8-bitAuto-Reload 02H
OAH
two 6-bitTimera 03H
OBH
As a Counter:
Table 4
TMOD
MODE
COUNTER 0
INTERNAL
EXTERNAL
FUNCTION
CONTROL CONTROL
(NOTE 1)
(NOTE 2)
o
13-bitTimer
04H
OCH
1
16-bitTimer 05H
ODH
2
8-bitAuto-Reload 06H
OEH
3
one8-bitCounter
07H
OFH
NOTES
1.TheTimeristurnedON/OFF
byeettinglclearingbitTROinthesotlwere.
2. The TimeriaturnedON/OFF
bythe 1 to Otransitionon~ (P3.2)whenTRO= 1
(herdwarecontrol).
2-15

Intel MCS 51 Specifications

General

Brand	Intel
Model	MCS 51
Category	Microcontrollers
Language	English