User’s Manual
6-25
05.99
On-Chip Peripheral Components
C513AO
Special Function Register T2CON (Address C8H)
Reset Value: 00H
Bit
Function
TF2
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.
EXF2
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)
RCLK
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.
TCLK
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.
EXEN2
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.
TR2
Start / Stop Control for Timer 2
TR2 = 1 starts Timer 2.
C/T2
Timer or Counter Select for Timer 2
C/T2 = 0 for timer function. C/T2 = 1 for external event counter (falling edge
triggered).
CP/RL2
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.
TF2
EXF2
RCLK
TCLK
C8H
T2CON
EXEN2
TR2
C/T2
CP/RL2
CFH
CEH
CDH
CCH
CBH
CAH
C9H
C8H
Bit No.
7
6
5
4
3
2
1
0
MSB
LSB