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Chapter 7 16-bit Timer
VII - 32
16-bit Timer Synchronous Output
7-8-2 Setup Example
Synchronous Output Setup Example (Timer 7)
Setup example that latched data of port 6 is output constantly (100 µs) by using timer 7 from the synchro-
nous output pin is shown below. The clock source of timer 7 is selected fs/4 (at fosc=8 MHz).
An example setup procedure, with a description of each step is shown below.
(1) Set the TM7EN flag of the timer 7 mode
register 1 (TM7MD1) to "0" to stop timer 7
counting.
(2) Set the SYOEVS1-0 flag of the pin control
register (FLOAT) to "01" to set the
synchronous output event to the timer 7
interrupt.
(3) Set the port 6 synchronous output control
register (P6SYO) to x'FF' to set the
synchronous output pin.
(P67 to P60 : Synchronous output pin)
Set the port 6 direction control register
(P6DIR) to x'FF' to set port 6 to output pin.
If it needs, pull-up resistor should be added.
(4) Set the TM7BCR flag of the TM7MD2 register
to "1" to select the compare match as a clear
source of the binary counter.
(5) Select fs as a clock source by the TM7CK1-0
flag of the TM7MD 1 register.
Also, select a 1/4 dividing as a clock source by
the TM7PS1-0 flag.
(6) Set the synchronous output event generation
cycle to the timer 7 preset register 1
(TM7PR1). To be 10 kHz by dividing 1 MHz,
set as follows ;
100 - 1 = 99 (x'0063')
At that time, the same value is loaded to the
timer 7 compare register 1 (TM7OC1), and
TM7BC is initialized to x'0000'.
Setup Procedure
(1) Stop the counter.
TM7MD1 (x'3F78')
bp4 : TM7EN = 0
(2) Select the synchronous output
event.
FLOAT (x'3F2E')
bp1-0 : SYOEVS1-0 = 01
(3) Set the synchronous output pin.
P6SYO (x'3F1E') = x'FF'
P6DIR (x'3F36') = x'FF'
(4) Select the condition of timer clear.
TM7MD2 (x'3F79')
bp5 : TM7BCR = 1
(5) Select the count clock source.
TM7MD1 (x'3F78')
bp1-0 : TM7CK1-0 = 01
bp3-2 : TM7PS1-0 = 10
(6) Set the synchronous output event
generation cycle.
TM7PR1 (x'3F75',x'3F74')=x'0063'
Description
[ Chapter 4 I/O Ports ]