45 lines
1.1 KiB
C
45 lines
1.1 KiB
C
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/*
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* Based on microbuilders PWM example.
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*/
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#include "lpc134x.h"
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#include "sysdefs.h"
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uint32_t brightness = 100;
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void backlightInit(void) {
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/* Enable the clock for CT16B1 */
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SCB_SYSAHBCLKCTRL |= (SCB_SYSAHBCLKCTRL_CT16B1);
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/* Configure PIO1.10 as Timer1_16 MAT1 Output */
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IOCON_PIO1_10 &= ~IOCON_PIO1_10_FUNC_MASK;
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IOCON_PIO1_10 |= IOCON_PIO1_10_FUNC_CT16B1_MAT1;
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/* Set default duty cycle (MR1) */
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TMR_TMR16B1MR1 = (0xFFFF * (100 - brightness)) / 100;
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/* External Match Register Settings for PWM */
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TMR_TMR16B1EMR = TMR_TMR16B1EMR_EMC1_TOGGLE | TMR_TMR16B1EMR_EM1;
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/* enable Timer1 */
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TMR_TMR16B1TCR = TMR_TMR16B1TCR_COUNTERENABLE_ENABLED;
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/* Enable PWM1 */
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TMR_TMR16B1PWMC = TMR_TMR16B1PWMC_PWM1_ENABLED;
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}
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int backlightSetBrightness(uint32_t percentage) {
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if ((percentage < 1) || (percentage > 100)) {
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/* brightness must be a value between 1 and 100 */
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return -1;
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}
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/* Set Duty Cycle (MR1) */
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TMR_TMR16B1MR1 = (0xFFFF * (100 - (brightness = percentage))) / 100;
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return 0;
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}
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uint32_t backlightGetBrightness(void) {
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return brightness;
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}
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