W77C32_07 Datasheet, PDF (56/78 Pages) Winbond – 8-BIT MICROCONTROLLER

W77C32/W77C032A
12.2.4 Baud Rate Generator Mode
The baud rate generator mode is enabled by setting either the RCLK or TCLK bits in T2CON register.
While in the baud rate generator mode, Timer/Counter 2 is a 16 bit counter with auto reload when the
count rolls over from FFFFh. However, rolling over does not set the TF2 bit. If EXEN2 bit is set, then a
negative transition of the T2EX pin will set EXF2 bit in the T2CON register and cause an interrupt
request.
Clock Source
Mode input
div. by 4 osc/2
div. by 64 osc/32
div. by 1024 osc/512
T2 = P1.0
TR2 = T2CON.2
T2EX = P1.1
EXEN2 = T2CON.3
C/T = T2CON.1
0
1
TL2 TH2
Timer 2
overflow
RCAP2L RCAP2H
EXF2
T2CON.6
Timer 2
Interrupt
Figure 17. Baud Rate Generator Mode
12.2.5 Programmable Clock-out
Timer 2 is equipped with a new clock-out feature which outputs a 50% duty cycle clock on P1.0. It can
be invoked as a programmable clock generator. To configure Timer 2 with clock-out mode, software
must initiate it by setting bit T2OE = 1, C/T2 = 0 and CP/RL = 0. Setting bit TR2 will start the timer.
This mode is similar to the baud rate generator mode, it will not generate an interrupt while Timer 2
overflow. So it is possible to use Timer 2 as a baud rate generator and a clock generator at the same
time. The clock-out frequency is determined by the following equation:
The Clock-out Frequency = Oscillator Frequency / [4 X (RCAP2H, RCAP2L) ]
Clock Source
Mode input
div. by 4 osc/2
div. by 64 osc/32
div. by 1024 osc/512
TR2 = T2CON.2
T2EX = P1.1
EXEN2 = T2CON.3
TL2 TH2
RCAP2L RCAP2H
Figure 18. Programmable Clock-Out Mode
1/2
T2=P1.0
EXF2
T2CON.6
Timer 2
Interrupt
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