C868_02 Datasheet, PDF (72/244 Pages) Infineon Technologies AG – 8 - Bit CMOS Microcontroller

C868
On-Chip Peripheral Components
4.6.6 Capture Mode
In order to enter the 16-bit capture mode, bits CP/RL2 and EXEN2 in register T2CON
must be set. In this mode, the down count function must remain disabled. The timer/
counter functions as a 16-bit timer or counter and always counts up to FFFF_H and
overflows. Upon an overflow condition, bit TF2 is set and the timer/counter reloads its
registers with 0000_H. The setting of TF2 generates an interrupt request to the core.
Additionally, with a falling edge on pin T2EX the contents of the timer/counter registers
(T2L/H) are captured into the RC2L/H registers. If the capture signal is detected while
the counter is being incremented, the counter is first incremented before the capture
operation is performed. This ensures that the latest value of the timer/counter registers
are always captured.
When the capture operation is completed, bit EXF2 is set and can be used to generate
an interrupt request. Figure 4-8 describes the capture function of timer/counter 2.
f_SYS 12
C/T2 = 0
C/T2 = 1
TR2
Pin
T2
T2L/H
Overflow
RC2L/H
Pin
T2EX
EXEN2
Figure 4-8 Capture Mode
User’s Manual
4-28
TF2
Timer 2
OR
Interrupt
EXF2
V 0.4, 2002-01