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Chapter 7 16-bit Timer
16-bit Timer Pulse Output
7-5-2 Setup Example
Timer Pulse Output Setup Example (Timer 7)
TM7IO pin outputs 50 kHz pulse by using timer 7. For this, select fosc as clock source, and set a 1/2
cycle (100 kHz) for the timer 7 compare register (at fosc=20 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 P1OMD4 flag of the port 1 output mode
register (P1OMD) to "1" to set P14 pin as the
special function pin. Set the P1DIR4 flag of the
port 1 direction control register (P1DIR) to "1"
to set output mode.
If it needs, pull-up resistor should be added.
(3) Set the TM7PWM flag of the timer 7 mode
register 2 (TM7MD2) to "0" to select the timer
pulse output.
(4) Set the TM7BCR flag of the TM7MD2 register
to "1" to select the compare match as a clear
source of a binary counter .
(5) Select fosc as an clock source by the
TM7CK1-0 flag of the TM7MD1 register.
Also, select 1/1 frequency as an count clock
source by the TM7PS1-0 flag.
Setup Procedure
(1) Stop the counter.
TM7MD1 (x'3F78')
bp4 : TM7EN = 0
(2) Set the special function pin to output
mode.
P1OMD (x'3F2F')
bp4 : P1OMD4 = 1
P1DIR (x'3F31')
bp4 : P1DIR4 = 1
(3) Set the timer pulse output.
TM7MD2 (x'3F79')
bp4 : TM7PWM = 0
(4) Select the condition for timer clear.
TM7MD2 (x'3F79')
bp5 : TM7BCR = 1
(5) Select the count clock source.
TM7MD1 (x'3F78')
bp1-0 : TM7CK1-0 = 00
bp3-2 : TM7PS1-0 = 00
Description
[ Chapter 4 I/O Ports ]