GMS90 Hynix Semiconductor, GMS90 Datasheet - Page 23

• Manufacturer Part Number: GMS90
• Description: 8-BIT SINGLE-CHIP MICROCONTROLLERS
• Manufacturer: Hynix Semiconductor

GMS90 Series
TIMER / COUNTER 0 AND 1
Timer/Counter 0 and 1 can be used in four operating modes as listed in Table 4:
Table 4. Timer/Counter 0 and 1 Operating Modes
In the "timer" function (C/T = "0") the register is incremented every machine cycle. Therefore the count rate is
f
In the "counter" function the register is incremented in response to a 1-to-0 transition at its corresponding exter-
nal input pin (P3.4/T0, P3.5/T1). Since it takes two machine cycles to detect a falling edge the max. count rate
is f
pulse width measurements. Figure 2 illustrates the input clock logic.
Figure 2. Timer/Counter 0 and 1 Input Clock Logic
Dec. 1998 Ver 3.0
OSC
OSC
Mode
/12.
0
1
2
3
/24. External inputs INT0 and INT1 (P3.2, P3.3) can be programmed to function as a gate to facilitate
8-bit timer/counter with a
divide-by-32 prescaler
16-bit timer/counter
8-bit timer/counter with
8-bit auto-reload
Timer/counter 0 used as
one 8-bit timer/counter and
one 8-bit timer Timer 1
stops
Max. f
Description
P3.2 / INT0
P3.3 / INT1
P3.4/T0
P3.5/T1
OSC
/24
f
OSC
TR0 / 1
TMOD
TCON
Gate
=1
Gate
12
X
X
X
X
C/T
X
X
X
X
TMOD
1
0
1
TMOD
C/T
M1
0
0
1
1
M0
&
0
1
0
1
f
OSC
f
f
f
OSC
OSC
OSC
internal
(12 32)
12
12
12
Input Clock
f
Timer 0/1
Input Clock
OSC
12
f
external (Max.)
OSC
f
f
f
OSC
OSC
OSC
(24 32)
24
24
24
19