C501_1 Datasheet, PDF (58/121 Pages) Siemens Semiconductor Group – 8-Bit Single-Chip Microcontroller

On-Chip Peripheral Components
C501
Special Function Register T2CON (Address C8H)
Reset Value : 00H
Bit No.
C8H
MSB
CF_H
CE_H
CD_H
CC_H
CB_H
TF2 EXF2 RCLK TCLK EXEN2
CA_H
TR2
LSB
C9_H C8_H
C/T2 CP/RL2 T2CON
Bit
TF2
EXF2
RCLK
TCLK
EXEN2
TR2
C/T2
CP/RL2
Function
Timer 2 Overflow Flag.
Set by a timer 2 overflow. Must be cleared by software. TF2 will not be set when
either RCLK = 1 or TCLK = 1.
Timer 2 External Flag.
Set when either a capture or reload is caused by a negative transition on T2EX
and EXEN2 = 1. When timer 2 interrupt is enabled, EXF2 = 1 will cause the CPU
to vector to the timer 2 interrupt routine. EXF2 must be cleared by software. EXF2
does not cause an interrupt in up/down counter mode (DCEN = 1, SFR T2MOD)
Receive Clock Enable.
When set, causes the serial port to use timer 2 overflow pulses for its receive
clock in serial port modes 1 and 3. RCLK = 0 causes timer 1 overflows to be used
for the receive clock.
Transmit Clock Enable.
When set, causes the serial port to use timer 2 overflow pulses for its transmit
clock in serial port modes 1 and 3. TCLK = 0 causes timer 1 overflow to be used
for the transmit clock.
Timer 2 External Enable.
When set, allows a capture or reload to occur as a result of a negative transition
on pin T2EX (P1.1) if timer 2 is not being used to clock the serial port. EXEN2 = 0
causes timer 2 to ignore events at T2EX.
Start / Stop Control for Timer 2.
TR2 = 1 starts timer 2.
Timer or Counter Select for Timer 2.
C/T2 = 0 for timer function. C/T2 = 1 for external event counter (falling edge
triggered).
Capture /Reload Select.
CP/RL2 = 1 causes captures to occur an negative transitions at pin T2EX if
EXEN2 = 1. CP/RL2 = 0 causes automatic reloads to occur when timer 2
overflows or negative transitions occur at pin T2EX when EXEN2 = 1. When
either RCLK = 1 or TCLK = 1, this bit is ignored and the timer is forced to auto-
reload on timer 2 overflow.
Semiconductor Group
6-24