C505-2RM SIEMENS [Siemens Semiconductor Group], C505-2RM Datasheet - Page 30

• Manufacturer Part Number: C505-2RM
• Description: 8-Bit CMOS Microcontroller
• Manufacturer: SIEMENS [Siemens Semiconductor Group]

Timer / Counter 0 and 1
Timer/Counter 0 and 1 can be used in four operating modes as listed in table 7 :
Table 7
Timer/Counter 0 and 1 Operating Modes
Mode
0
1
2
3
In the “timer” function (C/T = ‘0’) the register is incremented every machine cycle. Therefore the
count rate is
In the “counter” function the register is incremented in response to a 1-to-0 transition at its
corresponding external input pin (P3.4/T0, P3.5/T1). Since it takes two machine cycles to detect a
falling edge the max. count rate is
programmed to function as a gate to facilitate pulse width measurements. Figure 10 illustrates the
input clock logic.
Figure 10
Timer/Counter 0 and 1 Input Clock Logic
Semiconductor Group
Description
8-bit timer/counter with a
divide-by-32 prescaler
16-bit timer/counter
8-bit timer/counter with
8-bit autoreload
Timer/counter 0 used as one
8-bit timer/counter and one
8-bit timer
Timer 1 stops
f
OSC
P3.4/T0
P3.5/T1
Gate
(TMOD)
P3.2/INT0
P3.3/INT1
/6.
=1
OSC
f
OSC
/12. External inputs INT0 and INT1 (P3.2, P3.3) can be
M1
÷
_
<
0
1
1
1
6
1
TMOD
TR0
TR1
30
M0
0
1
0
1
C/T = 0
C/T = 1
&
f
internal
OSC
f
OSC
/6x32
Control
/6
Input Clock
f
Timer 0/1
Input Clock
OSC
MCS03117
C505A / C505CA
/6
external (max)
C505 / C505C
f
OSC
f
OSC
/12x32
1997-12-01
/12