GMS81C50 Datasheet, PDF (58/99 Pages) Hynix Semiconductor – 8-BIT SINGLE CHIP MICROCONTROLLERS

HYUNDAI
GMS81C50 Series
* Single/Modulo-N Mode
Timer0 (Timer1) can select initial (T0INIT, T1INIT of
TM01) output level of Timer Output port. If initial level is
``L``, Low-Data Register value of Timer Data Register is
transferred to comparator and T0OUT (T1OUT) is to be
``Low``, if initial level is High? High -Data Register is
transferred and to be ``High``. Single Mode can be set by
Mode Select bit (T0MOD, T1MOD) of Timer Mode Reg-
ister (TM0, TM1) to ``1`` When used as Single Mode,
Timer counts up and compares with value of Data Regis-
ter. If the result is same, Time Out interrupt occurs and
level of Timer Output port toggle, then counter stops as re-
set state. When used as Modulo-N Mode, T0MOD
(T1MOD) should be set ``0``. Counter counts up until the
value of Data Register and occurs Time-out interrupt. The
level of Timer Output port toggle and repeats process of
counting the value which is selected in Data Register.
During Modulo-N Mode, If interrupt select bit (T0IFS,
T1IFS) of Mode Register is ``0``, Interrupt occurs on ev-
ery Time-out. If it is ``1``, Interrupt occurs every second
time-out.
Note: (*note. Timer Output is toggled whenever time
out happen)
[ Single Mode ]
8bit / 16bit
counting
Timer Enable initial.
value toggle.
[ Modulo-N Mode ]
8bit / 16bit
counting
Timer-output toggle.
interrupt occurs.
count stop.
Timer Enable initial.
value toggle.
Timer-Output Toggle.
Int occurs (IFS = 1) Each 2nd time out.
Int occurs (IFS = 0) When Time out.
Figure 11-16 Operation Diagram for Single/Modulo-N Mode
(4) Timer 2
Timer2 operates as a up-counter. The content of T2DR are
compared with the contents of up-counter. If a match is
found. Timer2 interrupt (IFT2) is generated and the up-
counter is cleared to ``00 h``. Therefore, Timer2 executes
as a interval timer. Interrupt period is determined by the
count source clock for the Timer2 and content of T2DR.
When T2ST is set to ``1``, count value of Timer 2 is
cleared and starts counting-up. For clearing and starting
the Timer2. T2ST have to set to ``1`` after set to ``0``. In
order to write a value directly into the T2DR, T2ST should
be set to ``0``. Count value of Timer2 can be read at any
time.
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