GMS81C1102 / GMS81C1202
16. TIMER / COUNTER
The GMS81C1202 has two Timer/Counter registers. Each
module can generate an interrupt to indicate that an event
has occurred (i.e. timer match).
sponse to a 0-to-1 (rising edge) transition at its correspond-
ing external input pin, EC0.
And in 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.
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 ).
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
TM0 and TM1 as shown in Figure 16-1 and Table 16-1.
In the "counter" function, the register is increased in re-
Timer 0 Mode Register
ADDRESS : D0H
RESET VALUE : --000000
-
-
CAP0
T0CK2
T0CK1
T0CK0
T0CN
T0ST
TM0
CAP0
Capture mode selection bit.
0 : Disables Capture
1 : Enables Capture
T0CN
T0ST
Continue control bit
0 : Stop counting
1 : Start counting continuously
T0CK[2:0]
Input clock selection
Start control bit
0 : Stop counting
1 : Start countingn
000 : fxin
001 : fxin
010 : fxin
2
4
8
100 : fxin 128
÷
÷
÷
÷
101 : fxin 512
÷
110 : fxin 2048
÷
011 : fxin 32
111 : External Event ( EC0 )
÷
Timer 1 Mode Register
ADDRESS : D2H
RESET VALUE : 00000000
POL
16BIT
PWME
CAP1
T1CK1
T1CK0
T1CN
T1ST
TM1
POL
PWM Output Polarity
0 : Duty active low
1 : Duty active high
T1CK[2:0]
Input clock selection
00 : fxin
10 : fxin
8
÷
01 : fxin
2
11 : using the Timer 0 clock
÷
16BIT
PWME
CAP1
16-bit mode selection
0 : 8-bit mode
1 : 16-bit mode
T1CN
T1ST
Continue control bit
0 : Stop counting
1 : Start counting continuously
PWM enable bit
0 : Disables PWM
1 : Enables PWM
Start control bit
0 : Stop counting
1 : Start countingn
Capture mode selection bit.
0 : Disables Capture
1 : Enables Capture
Figure 16-1 Timer 0 and Timer 1 Mode Register
44
Jan. 2002 ver 2.0
HYNIX [ HYNIX SEMICONDUCTOR ]
