demo of driving MAX2719 dot matrix displays with STM32F103 Bluepill
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f103-dotmatrix/project/colorled.c

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1.3 KiB

#include "colorled.h"
#include "utils/timebase.h"
#define LONG_DELAY() for (volatile uint32_t __j = 4; __j > 0; __j--)
#define SHORT_DELAY() for (volatile uint32_t __j = 1; __j > 0; __j--)
static inline
__attribute__((always_inline))
void colorled_byte(uint8_t b)
{
for (register volatile uint8_t i = 0; i < 8; i++) {
COLORLED_GPIO->BSRR = COLORLED_PIN; // set pin high
// duty cycle determines bit value
if (b & 0x80) {
LONG_DELAY();
COLORLED_GPIO->BRR = COLORLED_PIN; // set pin low
SHORT_DELAY();
} else {
SHORT_DELAY();
COLORLED_GPIO->BRR = COLORLED_PIN; // set pin low
LONG_DELAY();
}
b <<= 1; // shift to next bit
}
}
/** Set one RGB LED color */
void colorled_set(uint32_t rgb)
{
__disable_irq(); // SysTick interrupt when sending data would break the timing
colorled_byte((rgb & 0x00FF00) >> 8);
colorled_byte((rgb & 0xFF0000) >> 16);
colorled_byte(rgb & 0x0000FF);
__enable_irq();
delay_us(50); // show
}
/** Set many RGBs */
void colorled_set_many(uint32_t *rgbs, int count)
{
__disable_irq();
for (int i = 0; i < count; i++) {
uint32_t rgb = *rgbs++;
colorled_byte((rgb & 0x00FF00) >> 8);
colorled_byte((rgb & 0xFF0000) >> 16);
colorled_byte(rgb & 0x0000FF);
}
__enable_irq();
delay_us(50); // show
}
void colorled_off(void)
{
colorled_set(RGB_BLACK);
}