Mikroelektronika MIKROE-350 Fiche De Données

311

- SOFTWARE AND HARDWARE SOLUTIONS FOR EMBEDDED WORLD

CHAPTER 6

You need a CMO on the given MCU (that supports PWM). 

Before calling this routine you must set the output pin for the PWM (according
to the datasheet):

DDRB.3 = 1; // set PORTB pin 3 as output for the PWM 

This code oxample is for ATmega16, for different MCU please consult datasheet
for the correct pinout of the PWM module or modules.

Initialize PWM module:

PWM_Init(_PWM_FAST_MODE, _PWM_PRESCALER_8, _PWM_NON_INVERTED,

127)

sub procedure PWM_Set_Duty(dim duty as byte)

Nothing.

Changes PWM duty ratio. Parameter duty takes values from 0 to 255, where 0
is 0%, 127 is 50%, and 255 is 100% duty ratio. Other specific values for duty
ratio can be calculated as 

(Percent*255)/100

.

PWM module must to be initialised (PWM_Init) before using PWM_Set_Duty
function.

For example lets set duty ratio to 75%:

PWM_Set_Duty(192)

sub procedure PWM_Start()

Nothing.

Starts PWM. 

MCU must have CMO module to use this library. PWM_Init must be called
before 
using this routine.

PWM_Start()