74 lines
2.3 KiB
C
74 lines
2.3 KiB
C
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#include <libopencm3/stm32/gpio.h>
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#include "fan_ctrl_dc.h"
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#include "pinout.h"
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void fan_ctrl_dc_init(void)
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{
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// configure the GPIOs: DC/DC disabled by default
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gpio_clear(DCDC_PORT, DCDC_EN_PIN);
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gpio_mode_setup(DCDC_PORT, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, DCDC_EN_PIN);
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// configure the feedback resistor GPIOs. These are used as open-drain
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// outputs, so either they are configured as input or as output, but the
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// only valid output value is 0.
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gpio_clear(DCDC_PORT, DCDC_CTRL_FB0_PIN | DCDC_CTRL_FB1_PIN | DCDC_CTRL_FB2_PIN | DCDC_CTRL_FB3_PIN);
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gpio_mode_setup(DCDC_PORT, GPIO_MODE_INPUT, GPIO_PUPD_NONE,
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DCDC_CTRL_FB0_PIN | DCDC_CTRL_FB1_PIN | DCDC_CTRL_FB2_PIN | DCDC_CTRL_FB3_PIN);
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}
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void fan_ctrl_dc_enable(void)
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{
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// enable the DC/DC converter
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gpio_set(DCDC_PORT, DCDC_EN_PIN);
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}
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void fan_ctrl_dc_disable(void)
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{
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// shut down the DC/DC converter and disable all feedback resistors.
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gpio_clear(DCDC_PORT, DCDC_EN_PIN);
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gpio_mode_setup(DCDC_PORT, GPIO_MODE_INPUT, GPIO_PUPD_NONE,
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DCDC_CTRL_FB0_PIN | DCDC_CTRL_FB1_PIN | DCDC_CTRL_FB2_PIN | DCDC_CTRL_FB3_PIN);
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}
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void fan_ctrl_dc_set_duty(uint8_t percent)
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{
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// note: as we only have 4 switchable feedback resistors, there are only 16
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// voltage steps available.
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uint8_t step = 15 * (uint16_t)percent / 100;
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// if a resistor is active, the output voltage increases. The smallest
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// resistor (FB0) has the strongest influence on the output voltage.
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// Therefore, FB0 corresponds to the MSB of the calculated step.
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if(step & (1 << 3)) {
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gpio_mode_setup(DCDC_PORT, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, DCDC_CTRL_FB0_PIN);
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} else {
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gpio_mode_setup(DCDC_PORT, GPIO_MODE_INPUT, GPIO_PUPD_NONE, DCDC_CTRL_FB0_PIN);
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}
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if(step & (1 << 2)) {
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gpio_mode_setup(DCDC_PORT, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, DCDC_CTRL_FB1_PIN);
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} else {
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gpio_mode_setup(DCDC_PORT, GPIO_MODE_INPUT, GPIO_PUPD_NONE, DCDC_CTRL_FB1_PIN);
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}
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if(step & (1 << 1)) {
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gpio_mode_setup(DCDC_PORT, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, DCDC_CTRL_FB2_PIN);
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} else {
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gpio_mode_setup(DCDC_PORT, GPIO_MODE_INPUT, GPIO_PUPD_NONE, DCDC_CTRL_FB2_PIN);
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}
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if(step & (1 << 0)) {
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gpio_mode_setup(DCDC_PORT, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, DCDC_CTRL_FB3_PIN);
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} else {
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gpio_mode_setup(DCDC_PORT, GPIO_MODE_INPUT, GPIO_PUPD_NONE, DCDC_CTRL_FB3_PIN);
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}
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}
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