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C501_1 Datasheet, PDF (51/121 Pages) Siemens Semiconductor Group – 8-Bit Single-Chip Microcontroller | |||
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On-Chip Peripheral Components
C501
Special Function Register TMOD (Address 89H)
Reset Value : 00H
Bit No. MSB
LSB
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
Function
Gating control
When set, timer/counter âxâ is enabled only while âINT xâ pin is high and âTRxâ
control bit is set.
When cleared timer âxâ is enabled whenever âTRxâ control bit is set.
Counter or timer select bit
Set for counter operation (input from âTxâ input pin).
Cleared for timer operation (input from internal system clock).
Mode select bits
M1
M0
Function
0
0
8-bit timer/counter:
âTHxâ operates as 8-bit timer/counter
âTLxâ serves as 5-bit prescaler
0
1
16-bit timer/counter.
âTHxâ and âTLxâ are cascaded; there is no prescaler
1
0
8-bit auto-reload timer/counter.
âTHxâ holds a value which is to be reloaded into âTLxâ each
time it overflows
1
1
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
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