crashtest-r0ket/lcd/backlight.c

58 lines
1.4 KiB
C

/*
* Based on microbuilders PWM example.
*/
#include "lpc134x.h"
#include "sysdefs.h"
#include "core/gpio/gpio.h"
#include "basic/basic.h"
uint32_t brightness = 100;
void backlightInit(void) {
/* Enable the clock for CT16B1 */
SCB_SYSAHBCLKCTRL |= (SCB_SYSAHBCLKCTRL_CT16B1);
/* Configure PIO1.9 as Timer1_16 MAT0 Output */
IOCON_PIO1_9 &= ~IOCON_PIO1_9_FUNC_MASK;
IOCON_PIO1_9 |= IOCON_PIO1_9_FUNC_CT16B1_MAT0;
/* Set default duty cycle (MR1) */
TMR_TMR16B1MR0 = (0xFFFF * (100 - brightness)) / 100;
/* External Match Register Settings for PWM */
TMR_TMR16B1EMR = TMR_TMR16B1EMR_EMC0_TOGGLE | TMR_TMR16B1EMR_EM0;
/* enable Timer1 */
TMR_TMR16B1TCR = TMR_TMR16B1TCR_COUNTERENABLE_ENABLED;
/* Enable PWM0 */
TMR_TMR16B1PWMC = TMR_TMR16B1PWMC_PWM0_ENABLED;
// Enable Step-UP
gpioSetDir(RB_PWR_LCDBL, gpioDirection_Output);
gpioSetValue(RB_PWR_LCDBL, 0);
}
int backlightSetBrightness(uint32_t percentage) {
if ((percentage < 0) || (percentage > 100)) {
/* brightness must be a value between 1 and 100 */
return -1;
}
if( percentage == 0 ){
gpioSetDir(RB_PWR_LCDBL, gpioDirection_Input);
}else{
gpioSetDir(RB_PWR_LCDBL, gpioDirection_Output);
gpioSetValue(RB_PWR_LCDBL, 0);
}
/* Set Duty Cycle (MR1) */
TMR_TMR16B1MR0 = (0xFFFF * (100 - (brightness = percentage))) / 100;
return 0;
}
uint32_t backlightGetBrightness(void) {
return brightness;
}