C868_02 Datasheet, PDF (74/244 Pages) Infineon Technologies AG – 8 - Bit CMOS Microcontroller

C868
On-Chip Peripheral Components
f_SYS 12
C/T2 = 0
C/T2 = 1
TR2
Pin
T2
T2L/H
OV_CLK
Overflow
RC2L/H
Pin
T2EX
EXEN2
Timer 2
EXF2
Interrupt
Figure 4-9 Baudrate Generator Mode
4.6.8 Count Clock
The count clock for the auto-reload mode is chosen by the bit C/T2 in register T2CON.
If C/T2 = 0, a count clock of f_SYS/12 is used for the count operation.
If C/T2 = 1, timer 2 behaves as a counter that counts 1-to-0 transitions of input pin T2.
The counter samples pin T2 over 2 f_SYS cycles. If a 1 was detected during the first clock
and a 0 was detected in the following clock, then the counter increments by one.
Therefore, the input levels should be stable for at least 1 clocks.
4.6.9 Module Powerdown
The timer/counter 2 is disabled when the chip goes into the powerdown mode as
describe in . Or it can be individually disabled by setting T2DIS in register PMCON1.
This helps to reduce current consumption in the normal, slow down and idle modes of
operation if the timer/counter 2 is not utilized. Bit T2ST in register PMCON2 reflects the
powerdown status of timer/counter 2.
User’s Manual
4-30
V 0.4, 2002-01