ledbp.h

#define HT16K33_CMD_BLINK	0x80
#define HT16K33_CMD_BRIGHTNESS	0xE0

enum blink_values
{
	HT16K33_BLINK_NONE=0,
	HT16K33_BLINK_500MS,
	HT16K33_BLINK_1000MS,
	HT16K33_BLINK_2000MS
};


uint8_t ledbp_i2c_port = 0;
uint8_t ledbp_i2c_addr = 0x70;


esp_err_t ledbp_write_reg(uint8_t command)
{
	const esp_err_t ret = i2c_master_write_to_device
	(
		ledbp_i2c_port,
		ledbp_i2c_addr,
		&command,
		1,
		I2C_MASTER_TIMEOUT_MS / portTICK_PERIOD_MS
	);
	return ret;
}


esp_err_t ledbp_write_buf(const uint8_t* buffer, uint8_t sz)
{
	const esp_err_t ret = i2c_master_write_to_device
	(
		ledbp_i2c_port,
		ledbp_i2c_addr,
		buffer,
		sz,
		I2C_MASTER_TIMEOUT_MS / portTICK_PERIOD_MS
	);
	return ret;
}


esp_err_t ledbp_write_screen(const uint8_t pixbuf[8])
{
	uint8_t buffer[2*8+1];
	uint8_t* writer = buffer;
	*writer++ = 0x00; // start at address $00
	for (uint8_t i = 0; i < 8; i++)
	{
		*writer++ = pixbuf[i];	// eight monochrome pixels.
		*writer++ = 0x00;	// high bytes are unused.
	}
	return ledbp_write_buf(buffer, sizeof(buffer));
}


void ledbp_set_brightness(uint8_t level)
{
	level = level > 15 ? 15 : level;
	uint8_t command = HT16K33_CMD_BRIGHTNESS | level;
	ledbp_write_reg(command);
}


void ledbp_set_blink_rate(uint8_t rate)
{
	rate = rate > 3 ? 3 : rate;
	uint8_t command = HT16K33_CMD_BLINK | 1 | (rate << 1);
	ledbp_write_reg(command);
}


void ledbp_init(uint8_t portnr, uint8_t addr)
{
	// Save the port and addr settings.
	ledbp_i2c_port = portnr;
	ledbp_i2c_addr = addr;

	// turn on oscillator.
	ledbp_write_reg(0x21);
	// not too bright.
	ledbp_set_brightness(10);
	// let's blink.
	ledbp_set_blink_rate(HT16K33_BLINK_500MS);
}