Panasonic MN101C77C, F77G user manual P1OMD0, P1DIR0

Chapter 6 8-bit Timers

6-5-2 Setup Example

„Timer Pulse Output Setup Example (Timers 0, 1, 4 and 5)

TM0IO (P10) pin outputs 50 kHz pulse by using timer 0. For this, select fosc as clock source, and set a 1/ 2 cycle (100 kHz) for the timer 0 compare register (at fosc=20 MHz).

An example setup procedure, with a description of each step is shown below.

	Setup Procedure					Description
(1)	Stop the counter.			(1)	Set the TM0EN flag of the timer 0 mode
	TM0MD (x'3F54')				register (TM0MD) to "0" to stop timer 0
	bp3	:TM0EN	= 0		counting.
(2)	Set the special function pin to the			(2)	Set the P1OMD0 flag of the port 1 output mode
	output mode.				register (P1OMD) to "1" to set P10 the special
	P1OMD (x'3F2F')				function pin.
	bp0	:P1OMD0	= 1		Set the P1DIR0 flag of the port 1 direction
	P1DIR (x'3F31')				control register (P1DIR) to "1" to set output
	bp0	:P1DIR0	= 1		mode.
					If it needs, pull-up resister should be added.
					[	Chapter 4. I/O Ports ]
(3)	Select the normal timer operation.			(3)	Set the TM0PWM flag and TM0MOD flag of
	TM0MD (x'3F54')				the TM0MD register to "0" to select the normal
	bp4	:TM0PWM	= 0		timer operation.
	bp5	:TM0MOD	= 0
(4)	Select the count clock source.			(4)	Select fosc for the clock source by the
	TM0MD (x'3F54')				TM0CK2-0 flag of the TM0MD register.
	bp2-0	:TM0CK2-0 = 000
(5)	Set the timer pulse output cycle.			(5)	Set the timer 0 compare register (TM0OC) to
	TM0OC (x'3F52')		= x'C7'		the 1/2 of the timer pulse output cycle.
					The setting value should be 200-1=199(x'C7'),
					because 100 kHz is divided by 20 MHz.
					At that time, the timer 0 binary counter
					(TM0BC) is initialized to x'00'.
(6)	Start the timer operation.			(6)	Set the TM0EN flag of the TM0MD register to
	TM0MD (x'3F54')				"1" to start timer 0.
	bp3	:TM0EN	= 1

VI - 24 8-bit Timer Pulse Output