#include <ring-light/dmx.h>
#include <stm32f0xx.h>

static volatile bool dmx_new_data_avail = false;
static uint32_t dmx_base_channel;
static uint8_t dmx_channel_data[DMX_USED_CHANNEL_COUNT];

void dmx_init(uint32_t base_channel)
{
	int i;
	uint8_t *ptr;

	dmx_new_data_avail = false;
	for (i = 0, ptr = dmx_channel_data; i < DMX_USED_CHANNEL_COUNT; i++, ptr++) {
		*ptr = 0u;
	}

	dmx_base_channel = base_channel;

	/* Enable GPIOA and USART1 clock */
	RCC->AHBENR |= RCC_AHBENR_GPIOAEN;
	RCC->APB2ENR |= RCC_APB2ENR_USART1EN;

	/* Switch RXTX pin low, activating permanent READ mode */
	GPIOA->MODER |= (0x1<<(2*5));
	GPIOA->BRR |= (1<<5);

	/* Switch PA10 to RX alternate function of USART1 (AF1) */
	GPIOA->MODER |= (0x2<<(2*10));
	GPIOA->AFR[1] |=(0x1<<(4*2));

	/* Set baudrate: 48MHz / 250k = 129 */
	USART1->BRR = 192u;
	USART1->CR3 = USART_CR3_EIE;
	USART1->CR2 = USART_CR2_STOP_1;
	USART1->CR1 = USART_CR1_RXNEIE | USART_CR1_RE | USART_CR1_UE;

	NVIC_EnableIRQ(USART1_IRQn);
}

bool dmx_new_data_available()
{
	return dmx_new_data_avail;
}

const uint8_t *dmx_get_data()
{
	return dmx_channel_data;
}

void USART1_IRQHandler(void)
{
	uint32_t isr;
	volatile uint8_t dreg;

	isr = USART1->ISR;
	USART1->ICR = USART_ICR_ORECF | USART_ICR_NCF | USART_ICR_FECF;

	if (isr & USART_ISR_RXNE) {
		dreg = (uint8_t)USART1->RDR;
		dmx_channel_data[0] = dreg;
	}

	__DSB();
}