Sonic Alert msm85c154hvs Clock Radio User Manual


 
MSM80C154S/83C154S/85C154HVS
88
4.5.2.5.5 Mode 3
M1 M0
11
In mode 3, timer/counter 0 TL0 and TH0 become independent 8-bit timer/counters by the
circuit connection shown in Figure 4-17. Timer/counter 1 does not operate when mode 3 is
set. The TL0 8-bit timer/counter is controlled in the same way as the regular timer/counter 0,
TF0 being set if a carry signal is generated by TL0.
The TH0 8-bit timer/counter is controlled only by TR1, and the control only covers count
starting and stopping. TF1 is set by a carry signal generated by TH0.
When timer/counter 0 is set to mode 3, timer/counter 1 can operate in modes 0, 1, or 2, and
be used by the serial port clock. Control of timer/counter 1 count starting and stopping in this
case is handled between operating mode and mode 3. If mode 3 is set, the timer/counter 1
counting operation is stopped.
DETECTOR
XTAL 1 ÷
12 S3
GATE
C/
T
DATA
INT
0 PIN
(PORT 3.2)
LATCHS5
Q
TR0
T0 PIN
(PORT 3.4)
Q0------Q7
TL0
(8BITS)
C
DETECTOR TF0
XTAL 1 ÷
12
Q0------Q7
TH0
(8BITS)
DETECTOR TF1
TR1
Figure 4-17 Timer/counter 0 mode 3