67 lines
1.7 KiB
C
67 lines
1.7 KiB
C
#include <libopencm3/stm32/gpio.h>
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#include <libopencm3/stm32/timer.h>
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#include "libopencm3/stm32/common/timer_common_all.h"
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#include "pinout.h"
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#include "charge_pump.h"
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void charge_pump_init(void)
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{
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// set alternate function to Timer 1, channel 1 output
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gpio_set_af(CHARGE_PUMP_PORT, GPIO_AF2, CHARGE_PUMP_DRV_PIN);
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// set the GPIO to low until the charge pump is started
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gpio_clear(CHARGE_PUMP_PORT, CHARGE_PUMP_DRV_PIN);
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gpio_mode_setup(CHARGE_PUMP_PORT, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, CHARGE_PUMP_DRV_PIN);
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// *** TIM1 ***
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// Configure channel 1 for PWM
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// Ch1 = charge pump output
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timer_set_mode(TIM1, TIM_CR1_CKD_CK_INT, TIM_CR1_CMS_EDGE, TIM_CR1_DIR_UP);
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// set up PWM channel
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timer_set_oc_mode(TIM1, TIM_OC1, TIM_OCM_PWM1);
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timer_enable_oc_output(TIM1, TIM_OC1);
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timer_enable_oc_preload(TIM1, TIM_OC1);
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timer_set_oc_polarity_high(TIM1, TIM_OC1);
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// prescaler
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timer_set_prescaler(TIM1, 48 - 1); // Timer runs at 1 MHz
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// auto-reload value
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timer_set_period(TIM1, 2000 - 1); // overflow every 2000 cycles = 500 Hz
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// output compare value
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timer_set_oc_value(TIM1, TIM_OC1, 100); // High for 100 cycles = 100 μs
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// only generate interrupt on overflow
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timer_update_on_overflow(TIM1);
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// enable main output
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timer_enable_break_main_output(TIM1);
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}
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void charge_pump_start(void)
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{
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// start the timer
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timer_enable_counter(TIM1);
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// set mode to AF to pass through the PWM signal from the timer
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gpio_mode_setup(CHARGE_PUMP_PORT, GPIO_MODE_AF, GPIO_PUPD_NONE, CHARGE_PUMP_DRV_PIN);
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}
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void charge_pump_stop(void)
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{
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// stop the timer
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timer_disable_counter(TIM1);
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// set the output static low
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gpio_clear(CHARGE_PUMP_PORT, CHARGE_PUMP_DRV_PIN);
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gpio_mode_setup(CHARGE_PUMP_PORT, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, CHARGE_PUMP_DRV_PIN);
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}
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