C511_1 Datasheet, PDF (50/128 Pages) Siemens Semiconductor Group – 8-Bit CMOS Microcontroller

On-Chip Peripheral Units
Special Function Register TMOD (Address 89H)
Reset Value : 00H
MSB
LSB
Bit No. 7
6
5
4
3
2
1
0
89H Gate C/T M1 M0 Gate C/T M1 M0 TMOD
Timer 1 Control
Timer 0 Control
Bit
Gate
C/T
M1 M0
00
01
10
11
11
Function
Gating control.
When set, timer/counter "x" is enabled only while "INTx" pin is high and "TRx"
control bit is set.
When cleared timer "x" is enabled whenever "TRx" control bit is set.
Counter or timer select bit.
Set for counter operation (input from "Tx" input pin).
Cleared for timer operation (input from internal system clock).
Timer modes select bits
8-bit timer/counter.
"THx" operates as 8-bit timer/counter
"TLx" serves as 5-bit prescaler.
16-bit timer/counter.
"THx" and "TLx" are cascaded; there is no prescaler.
8-bit auto-reload timer/counter.
"THx" holds a value which is to be reloaded into "TLx" each time it overflows.
Timer 0:
TL0 is an 8-bit timer/counter controlled by the standard timer 0 control bits. TH0 is
an 8-bit timer only controlled by timer 1 control bits.
Timer 1:
Timer/counter 1 stops
Semiconductor Group
6-17