porklib: Simple library for programming Arduino in C
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avr-lib/lib/sipo_pwm.c

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1.4 KiB

#include <avr/io.h>
#include <stdbool.h>
#include <stdint.h>
#include "sipo_pwm.h"
#include "iopins.h"
#include "sipo_pwm_config.h"
/* -------- SIPO PWM MODULE ---------- */
/** Buffer for sending bits to SIPO */
bool _buff[SPWM_CHANNELS];
uint8_t spwm_levels[SPWM_CHANNELS];
/** Send _buff to SIPO */
void _send_buffer()
{
for (int8_t i = SPWM_CHANNELS - 1; i >= 0; i--)
{
#if (SPWM_INVERT)
set_pin(SPWM_DATA, !_buff[i]); /* Common anode */
#else
set_pin(SPWM_DATA, _buff[i]); /* Common cathode */
#endif
// send a CLK pulse
pin_high(SPWM_CLK);
pin_low(SPWM_CLK);
}
// send a STR pulse
pin_high(SPWM_STR);
pin_low(SPWM_STR);
}
void spwm_init()
{
// Pin directions
as_output(SPWM_CLK);
as_output(SPWM_STR);
as_output(SPWM_DATA);
// Initial states
pin_low(SPWM_CLK);
pin_low(SPWM_STR);
}
/**
* Display PWM channels.
* This could be called in a Timer ISR.
*/
void spwm_send()
{
// Set all bits to 1 (if their PWM level is 0, set to 0)
for (uint8_t bit = 0; bit < SPWM_CHANNELS; bit++)
{
_buff[bit] = (bool) spwm_levels[bit];
}
// Show initial state
_send_buffer();
// For each PWM level...
for (uint16_t pwm = 0; pwm < SPWM_COLOR_DEPTH; pwm++)
{
// Turn OFF bits that are below the level
for (uint8_t bit = 0; bit < SPWM_CHANNELS; bit++)
{
if (spwm_levels[bit] < pwm)
{
_buff[bit] = 0;
}
}
// And show...
_send_buffer();
}
}