Mikroelektronika MIKROE-742 데이터 시트

324

- SOFTWARE AND HARDWARE SOLUTIONS FOR EMBEDDED WORLD

CHAPTER 6

The N variable represents the prescaler factor (1, 8, 64, 256, or 1024). Some
modules also support 32 and 128 prescaler value, but for this you will need to
check the datasheet for the desired MCU)

PWM_Init must be called before using other functions from PWM Library.

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 example 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); 

procedure PWM_Set_Duty(duty : 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);

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();