display.c

#include "LCD/LCD_Driver.h"
#include "framebuffer.h"
#include "gfx.h"
#include "textbuffer.h"

#include "gpio.h"
#include "tmr.h"
#include "portexpander.h"
#include "MAX77650-Arduino-Library.h"

#include <stdint.h>
#include <stdio.h>
/***** Globals *****/
const gpio_cfg_t DEV_DC_PIN = { PORT_1, PIN_6, GPIO_FUNC_OUT, GPIO_PAD_NONE };

struct gfx_region display_screen;
struct txt_buffer display_textb;

// Parameters for PWM output
#define PORT_PWM PORT_0 // port
#define PIN_PWM PIN_28  // pin
#define FREQ 200        // (Hz)
//#define DUTY_CYCLE 75  // (%)
#define DUTY_CYCLE 20      // (%)
#define PWM_TIMER MXC_TMR4 // must change PORT_PWM and PIN_PWM if changed

/***** Functions *****/
void PWM_Output(void)
{
	// Declare variables
	gpio_cfg_t gpio_pwm;   // to configure GPIO
	tmr_cfg_t tmr;         // to congigure timer
	tmr_pwm_cfg_t tmr_pwm; // for configure PWM
	unsigned int period_ticks = PeripheralClock / FREQ;
	unsigned int duty_ticks   = period_ticks * DUTY_CYCLE / 100;

	// Congfigure GPIO port and pin for PWM
	gpio_pwm.func = GPIO_FUNC_ALT4;
	gpio_pwm.port = PORT_PWM;
	gpio_pwm.mask = PIN_PWM;
	gpio_pwm.pad  = GPIO_PAD_PULL_DOWN;

	if (GPIO_Config(&gpio_pwm) != E_NO_ERROR) {
		printf("Failed GPIO_Config for pwm.\n");
	}

	/* 
    Steps for configuring a timer for PWM mode:
    1. Disable the timer
    2. Set the prescale value
    3. Configure the timer for PWM mode
    4. Set polarity, pwm parameters
    5. Enable Timer
    */

	TMR_Disable(PWM_TIMER);

	TMR_Init(PWM_TIMER, TMR_PRES_1, 0);

	tmr.mode    = TMR_MODE_PWM;
	tmr.cmp_cnt = period_ticks;
	tmr.pol     = 0;
	TMR_Config(PWM_TIMER, &tmr);

	tmr_pwm.pol      = 1;
	tmr_pwm.per_cnt  = period_ticks;
	tmr_pwm.duty_cnt = duty_ticks;

	if (TMR_PWMConfig(PWM_TIMER, &tmr_pwm) != E_NO_ERROR) {
		printf("Failed TMR_PWMConfig.\n");