C509-L_97 SIEMENS [Siemens Semiconductor Group], C509-L_97 Datasheet - Page 112

• Manufacturer Part Number: C509-L_97
• Description: 8-Bit CMOS Microcontroller
• Manufacturer: SIEMENS [Siemens Semiconductor Group]

The bits T2PS, T2PS1, T2P1, and T2P0 are prescaler select bits. T2R1 and T2R0 select the reload
mode. T2I1 and T2I0 select the clock input source of timer 2. Bits ET2, EXEN2, EXF2, and TF2 are
interrupt control bits/flags. Detailed bit definition is given in the table below.
Bit
T2PS
T2P1
T2P0
T2PS1
T2R1
T2R0
T2I1
T2I0
ET2
Semiconductor Group
Symbol
Timer 2 prescaler select bits
Based on
input clock according the following table.
Timer 2 reload mode selection
Timer 2 input selection
Timer 2 Interrupt Enable.
If ET2 = 0, the timer 2 interrupt is disabled.
T2P1
0
0
0
0
1
1
1
1
T2I1
0
0
1
1
T2R1
0
1
1
f
T2I0
0
1
0
1
T2R0
X
0
1
OSC
T2P0
0
0
1
1
0
0
1
1
/6 these bits define the prescaler divider ratio of the timer 2
Input Mode
No input selected : timer 2 stops
Timer function : input frequency see table above
Counter function : external input controlled by pin
P1.7 / T2
Gated timer functiol : input controlled by pin T2/P1.7
Reload Mode
Reload disabled
Mode 0: auto-reload upon timer 2 overflow (TF2)
Mode 1: reload upon falling edge at pin P1.5 / T2EX
6-34
T2PS1
0
1
0
1
0
1
0
1
On-Chip Peripheral Components
Timer 2
Input Clock
T2PS=0
f
f
f
f
f
f
f
f
OSC
OSC
OSC
OSC
OSC
OSC
OSC
OSC
6
24
12
48
24
96
48
192
Timer 2
Input Clock
T2PS=1
f
f
f
f
f
f
f
f
OSC
OSC
OSC
OSC
OSC
OSC
OSC
OSC
12
48
24
96
48
192
96
384
1997-10-01
C509-L