GMS81C2020 Datasheet, PDF (51/92 Pages) Hynix Semiconductor – CMOS Single-Chip 8-Bit Microcontroller with A/D Converter & VFD Driver

Hyundai Micro Electronics
GMS81C2020/GMS81C2120
15. TIMER / COUNTER
The GMS81C2020 and GMS81C2120 has two Timer/
Counter registers. Each module can generate an interrupt
to indicate that an event has occurred (i.e. timer match).
Timer 0 and Timer 1 can be used either the two 8-bit Tim-
er/Counter or one 16-bit Timer/Counter by combining
them.
In the "timer" function, the register is increased every in-
ternal clock input. Thus, one can think of it as counting in-
ternal clock input. Since a least clock consists of 2 and
most clock consists of 2048 oscillator periods, the count
rate is 1/2 to 1/2048 of the oscillator frequency in Timer0.
And Timer1 can use the same clock source too. In addition,
Timer1 has more fast clock source ( 1/1 to 1/8 ).
In the "counter" function, the register is increased in re-
sponse to a 0-to-1 (rising & falling edge) transition at its
corresponding external input pin, EC0(Timer 0).
In addition the "capture" function, the register is increased
in response external interrupt same with timer function.
When external interrupt edge input, the count register is
captured into capture data register CDRx.
Timer1 is shared with "PWM" function and "Compare out-
put" function
It has seven operating modes: "8-bit timer/counter", "16-
bit timer/counter", "8-bit capture", "16-bit capture", "8-bit
compare output", "16-bit compare output" and "10-bit
PWM" which are selected by bit in Timer mode register
TMx as shown in Figure 15-1 and Table 12-1 .
Timer 0 Mode Register
TM0
-
-
CAP0 T0CK2 T0CK1 T0CK0 T0CN T0ST
ADDRESS : D0H
RESET VALUE : --000000
CAP0
T0CK[2:0]
Capture mode selection bit.
0 : Disables Capture
1 : Enables Capture
Input clock selection
000 : fXI ÷ 2100 : fXI ÷ 128
001 : fXI ÷ 4101 : fXI ÷ 512
010 : fXI ÷ 8110 : fXI ÷ 2048
011 : fXI ÷ 32111 : External Event (EC0)
Timer 1 Mode Register
T0CN
T0ST
TM1
POL
16BIT PWM1E CAP1 T1CK1 T1CK0
Continue control bit
0 : Stop counting
1 : Start counting continuously
Start control bit
0 : Stop counting
1 : Counter register is cleared and start again
T1CN T1ST
ADDRESS : D2H
RESET VALUE : 00000000
POL
16BIT
PWM1E
CAP1
PWM Output Polarity
0 :Duty active low
1 : Duty active high
16-bit mode selection
0 : 8-bit mode
1 : 16-bit mode
PWM enable bit
0 : Disables PWM
1 : Enables PWM
Capture mode selection bit.
0 : Disables Capture
1 : Enables Capture
T1CK[2:0]]
T1CN
T1ST
Input clock selection
00 : fXI 10 : fXI ÷ 8
01 : fXI ÷ 211 : using the Timer 0 clock
Continue control bit
0 : Stop counting
1 : Start counting continuously
Start control bit
0 : Stop counting
1 : Counter register is cleared and start again
Figure 15-1 Timer Mode Register ( TMx , x = 0~1 )
Nov. 1999 Ver 0.0
preliminary
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