W79E201 Datasheet, PDF (47/87 Pages) Winbond – 8-BIT MICROCONTROLLER

W79E201
Auto-reload Mode, Counting Up/Down
Timer/Counter 2 will be in auto-reload mode as an up/down counter if CP/RL2 bit in T2CON is cleared
and the DCEN bit in T2MOD is set. In this mode, Timer/Counter 2 is an up/down counter whose
direction is controlled by the T2EX pin. A 1 on this pin cause the counter to count up. An overflow
while counting up will cause the counter to be reloaded with the contents of the capture registers. The
next down count following the case where the contents of Timer/Counter equal the capture registers
will load an FFFFh into Timer/Counter 2. In either event a reload will set the TF2 bit. A reload will also
toggle the EXF2 bit. However, the EXF2 bit can not generate an interrupt while in this mode.
RCLK+TCLK=0, ^CP/RL2 =T2CON.0=0, DCEN=1
Down Counting Reload Value
0FFh 0FFh
1/4
osc
1/12
T2 = P1.0
TR2 = T2CON.2
T2M = CKCON.5
1
C/T = T2CON.1
0⁰
1
TL2 TH2
T2CON.7
TF2
Timer 2
Interrupt
T2EX = P1.1
RCAP2L RCAP2H
Up Counting Reload Value
EXF2
T2CON.6
16-Bit Auto-reload Up/Down Counter
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.
RCLK+TCLK=0
osc
T2 = P1.0
TR2 = T2CON.2
C/T = T2CON.1
0
1
TL2 TH2
Timer 2
overflow
T2EX = P1.1
EXEN2 = T2CON.3
RCAP2L RCAP2H
Baud Rate Generator Mode
EXF2
T2CON.6
Timer 2
Interrupt
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Publication Release Date: December 16, 2004
Revision A2