gd32e232-wb2812.c

#include "gd32e232.h"
#include "systick.h"

// Speed 72MHz
// WB2812
// 0.35 µs == 350 ns
// 1 code   HIGH 400 ns 800 ns +- 150ns
// 0 code   HIGH 850 ns 450 ns +- 150ns
// RWA above 50µs

typedef enum {
  FALSE,
  TRUE
}
boolean;

boolean b = FALSE;

void delay_ns(uint32_t cycles) { //600 = 62ms 0.1

  // uint32_t cycles = ns * 72 / 1000; // calculate the number of cycles needed
  asm volatile(
    "mov r0, %[cycles]\n\t" // load the number of cycles into register r0
    "1: sub r0, #1\n\t" // decrement the value of r0 by 1
    "cmp r0, #0\n\t" // set flags based on the result of the subtraction
    "bne 1b\n\t" // branch back to label 1 if r0 is not zero
    : // no output operands
    : [cycles]
    "r"(cycles) // input operand: cycles is the number of cycles needed
    : "r0" // clobbered register: r0 is used as a counter
  );
}
void SetColorBit(boolean one) {
  if (one) {
    GPIO_BOP(GPIOB) = GPIO_PIN_0;
    delay_ns(4);

    GPIO_BC(GPIOB) = (uint32_t) GPIO_PIN_0;
    delay_ns(2);
  } else {
    GPIO_BOP(GPIOB) = GPIO_PIN_0;
    delay_ns(2);

    GPIO_BC(GPIOB) = (uint32_t) GPIO_PIN_0;
    delay_ns(4);
  }
}

void setColorByte(uint8_t color) {
  SetColorBit(color & (1) << 7);
  SetColorBit(color & (1) << 6);
  SetColorBit(color & (1) << 5);
  SetColorBit(color & (1) << 4);
  SetColorBit(color & (1) << 3);
  SetColorBit(color & (1) << 2);
  SetColorBit(color & (1) << 1);
  SetColorBit(color & (1));
}

volatile uint32_t id_value;

int main(void) {
  systick_config();

  /* enable the LED GPIO clock */
  rcu_periph_clock_enable(RCU_GPIOB);
  /* configure LED GPIO port */
  gpio_mode_set(GPIOB, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, GPIO_PIN_0);
  gpio_output_options_set(GPIOB, GPIO_OTYPE_PP, GPIO_OSPEED_50MHZ, GPIO_PIN_0);
  /* reset LED GPIO pin */
  gpio_bit_reset(GPIOB, GPIO_PIN_0);

  id_value = dbg_id_get();
  delay_1ms(1000);

  while (1) {
    for (int i = 0; i != 255; i++) {
      setColorByte(0);
      setColorByte(0);
      setColorByte(0);
      setColorByte(0);
      setColorByte(0);
      setColorByte(i);

      setColorByte(0);
      setColorByte(0);
      setColorByte(0);
      setColorByte(0);
      setColorByte(i);
      setColorByte(0);

      setColorByte(0);
      setColorByte(0);
      setColorByte(0);
      setColorByte(i);
      setColorByte(0);
      setColorByte(0);

      delay_1ms(50);
    }
  }
}