C509-L_97 Datasheet, PDF (113/290 Pages) Siemens Semiconductor Group – 8-Bit CMOS Microcontroller

On-Chip Peripheral Components
C509-L
Bit
EXEN2
EXF2
TF2
Symbol
Timer 2 external reload interrupt enable
If EXEN2 = 0, the timer 2 external reload interrupt is disabled.
The external reload function is not affected by EXEN2.
Timer 2 external reload flag
Set when a reload is caused by a negative transition on pin T2EX while
EXEN2 = 1. If ET2 in IEN0 is set (timer 2 interrupt enabled), EXF2 = 1 will
cause an interrupt. Can be used as an additional external interrupt when
the reload function is not used. EXF2 must be cleared by software.
Timer 2 overflow flag
Set by a timer 2 overflow and must be cleared by software. If the timer 2
interrupt is enabled, TF2 = 1 will cause an interrupt.
Special Function Registers TL2/TH2
(Addresses CCH/CDH)
Special Function Registers CRCL/CRCH (Addresses CAH/CBH)
Bit No. MSB
7
6
5
4
3
2
1
CCH .7
.6
.5
.4
.3
.2
.1
CDH
.7
.6
.5
.4
.3
.2
.1
Reset Value : 00H
Reset Value : 00H
LSB
0
.0 TL2
.0 TH2
CAH
.7
.6
.5
.4
.3
.2
.1
.0 CRCL
CBH
.7
.6
.5
.4
.3
.2
.1
.0 CRCH
Bit
TL2.7 - 0
TH2.7 - 0
CRCL.7 - 0
CRCH.7 - 0
Function
Timer 2 low byte
TL2 contains the 8-bit low byte of the 16-bit timer 2 count value.
Timer 2 high byte
TH2 contains the 8-bit high byte of the 16-bit timer 2 count value.
Compare/Reload/Capture register low byte
CRCL is the 8-bit low byte of the 16-bit reload register of timer 2. It is also used
for compare/capture functions.
Compare/Reload/Capture register high byte
CRCH is the 8-bit high byte of the 16-bit reload register of timer 2. It is also
used for compare/capture functions.
Semiconductor Group
6-35
1997-10-01