GMS81C7216 Datasheet, PDF (46/121 Pages) List of Unclassifed Manufacturers – 8-BIT SINGLE-CHIP MICROCONTROLLERS

GMS81C7208/7216
13. TIMER/EVENT COUNTER
The GMS81C7208/16 has four Timer/Event Counters. Each
module can generate an interrupt to indicate that an event has oc-
curred (i.e. timer match).
Timer 0 and timer 1 are can be used either two 8-bit Timer/
Counter or one 16-bit Timer/Counter with combine them. Also
timer 2 and timer 3 can be joined as a 16-bit Timer/Counter.
In the “timer” function, the register is increased every internal
clock input. Thus, one can think of it as counting internal clock
input. The count rate is 1/2 to 1/2048 of the oscillator frequency.
In the “counter” function, the register is incremented in response
to a 0-to-1 (rising edge) transition at its corresponding external
input pin, EC0 or EC2 pin.
In addition the “capture” function, the register is incremented in
response external or internal clock sources same with timer or
counter function. When external clock edge input, the count reg-
ister is captured into capture data register correspondingly.
It has five operating modes: “8-bit Timer/Counter”, “16-bit Tim-
er/Counter”, “8-bit capture”, “16-bit capture” which are selected
by bit in timer mode register TMn.
In operation of timer 2, timer 3, their operations are same with
timer 0, timer 1, respectively.
When programming the software, you may refer to following ex-
ample.
Example 1:
Timer 0 = 8-bit timer mode, 8ms interval at 4MHz
Timer 1 = 8-bit timer mode, 4ms interval at 4MHz
Timer 2 = 16-bit event counter mode
LDM SCMR,#0
;Main clock mode
LDM TDR0,#249
LDM TM0,#0001_0011B
LDM TDR1,#124
LDM TM1,#0000_1111B
LDM TDR2,#1FH
LDM TDR3,#4CH
LDM TM2,#0001_1111B
LDM TM3,#0100_1100B
SET1 T0E
SET1 T2E
EI
:
:
Example 2:
Timer0 = 16-bit timer mode, 0.5s at 4MHz
Timer2 = 2ms 8-bit timer mode at 4MHz
Timer3 = 250us 8-bit timer mode at 4MHz
LDM SCMR,#0
;Main clock mode
LDM TDR0,#23H
LDM TDR1,#0F4H
LDM TM0,#0FH ;FXIN/32, 8us
LDM TM1,#4CH
LDM TDR2,#249
LDM TDR3,#124
LDM TM2,#0FH ;FXUN/32, 8us
LDM TM3,#0DH ;FXIN/8, 2us
SET1 T0E
SET1 T2E
SET1 T3E
EI
:
:
Example 3:
Timer0 = 8-bit timer mode, 2ms interval at 4MHz
Timer1 = 8-bit capture mode, 2us sampling count.
LDM TDR0,#249 ;250x8=2000us
LDM TM0,#0FH ;FXIN/32, 8us
LDM IEDS,#XXXX_01XXB ;FALLING
LDM PMR,#XXXX_XX1XB ;AS INT1
LDM TDR1,#0FFH
LDM TM1,#0001_1011B ;2us
SET1
SET1
SET1
EI
:
:
T0E
T1E
INT1E
;ENABLE TIMER 0
;ENABLE TIMER 1
;ENABLE EXT. INT1
X: don’t care.
Example 4:
Timer0 = 8-bit timer mode, 2ms interval at 4MHz
Timer2 = 16-bit capture mode, 8us sampling count.
LDM TDR0,#249
LDM TM0,#0FH
LDM IEDS,#XX11_XXXXB
LDM PMR4,#XXXX_X1XXB
LDM TDR2,#0FFH
LDM TDR3,#0FFH
LDM TM2,#XX10_1111B
LDM TM3,#X10X_11XXB
;MAX
;MAX
;/32
SET1
SET1
SET1
EI
:
:
X: don’t care.
T0E
T2E
INT2E
;ENABLE TIMER 0
;ENABLE TIMER 2
;ENABLE EXT. INT2
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FEB. 2005 Ver 1.04