Figure 11-7. Timer 2 in Auto-Reload Mode (DCEN=0)
Fosc
12
"0"
"1"
T2 Pin
(P1.0)
TL2
(8 Bits)
TR2
Reload
TH2
(8 Bits)
Overflow
TF2
C/-T2
Timer 2
Interrupt
RCAP2L RCAP2H
Transition
Detector
T2EX Pin
(P1.1)
EXEN2
* Fosc is the system clock.
EXF2
Figure 11-8. Timer 2 in Auto-Reload Mode (DCEN=1)
Down Counting Reload Value
Toggle
FFH
FFH
Reload
EXF2
Fosc
12
"0"
"1"
T2 Pin
(P1.0)
TL2
(8 Bits)
TR2
TH2
(8 Bits)
Overflow
TF2
Timer 2
Interrupt
C/-T2
Reload
RCAP2L RCAP2H
Up Counting Reload Value
* Fosc is the system clock.
Counting Direction:
1 = Up
0 = Down
T2EX Pin
(P1.1)
11.2.3 Baud Rate Generator Mode
Bits TCLK and/or RCLK in T2CON register allow the serial port transmit and receive baud rates to be derived
from either Timer 1 or Timer 2. When TCLK=0, Timer 1 is used as the serial port transmit baud rate generator.
When TCLK= 1, Timer 2 is used as the serial port transmit baud rate generator. RCLK has the same effect for the
serial port receive baud rate. With these two bits, the serial port can have different receive and transmit baud
rates – one generated by Timer 1, the other by Timer 2.
Figure 11-9 shows the Timer 2 in baud rate generation mode. The baud rate generation mode is like the auto-
reload mode, in that a rollover in TH2 causes the Timer 2 registers to be reloaded with the 16-bit value in
registers RCAP2H and RCAP2L, which are preset by software.
The baud rates in modes 1 and 3 are determined by Timer 2’s overflow rate given below:
16
The timer can be configured for either “Timer” or “Counter” operation. In many applications, it is configured for
Mode 1 and 3 Baud Rates =
Timer 2 Overflow Rate
47
MPC82G516A Data Sheet
MEGAWIN
MEGAWIN [ MEGAWIN TECHNOLOGY CO., LTD ]
