SDA5250 Datasheet, PDF (83/143 Pages) Siemens Semiconductor Group – TVTEXT 8-Bit Microcontroller

SDA 525x
Timer/Counter Mode Register
Timer 0/1 Mode Register
Default after reset: 00_H
(MSB)
GATE
C/T
M1
TMOD
SFR-Address 89_H
M0
GATE
C/T
(LSB)
M1
M0
Timer 1
Timer 0
GATE
C/T
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.
Timer or counter selector. Cleared for timer operation (input
from internal system clock). Set for Counter operation (input
from “Tx” input pin).
Table 21
M1 M0
0
0
0
1
1
0
1
1
Operating Mode
SAB 8048 timer: “TLx” serves as five-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 eight-bit timer/counter controlled by the standard
timer 0 control bits; TH0 is an eight-bit timer only controlled
by timer 1 control bits.
(Timer 1) timer/counter 1 is stopped.
Semiconductor Group
83
1998-04-08