#include <Arduino.h>

const uint8_t LED = PC13;

#define DebugPort   Serial1 /* UART1 */

const uint8_t LENGTH = 96;
uint8_t buffer[LENGTH];
volatile bool dataReady = 0;

#define PERIPH_CLOCK1 36000000L
#define BAUDRATE 230400

void initLD() {
	// GPIO
	//enable clock access to GPIOA
	RCC->APB2ENR |= RCC_APB2ENR_IOPAEN;
	//Enable clock access to alternate function
	RCC->APB2ENR |= RCC_APB2ENR_AFIOEN;
	//Confgiure PA2 as output maximum speed to 50MHz
	// and alternate output push-pull mode
	GPIOA->CRL |= GPIO_CRL_MODE2;
	GPIOA->CRL |= GPIO_CRL_CNF2_1;
	GPIOA->CRL &= ~GPIO_CRL_CNF2_0;
	// Configure PA3 as Input floating
	// Set mode to be input
	GPIOA->CRL &= ~(GPIO_CRL_MODE3);
	GPIOA->CRL |= GPIO_CRL_CNF3_0;
	GPIOA->CRL &= ~GPIO_CRL_CNF3_1;
	// Don't remap the pins
	AFIO->MAPR &= ~AFIO_MAPR_USART2_REMAP;

	// USART2
	//enable clock access to USART2
	RCC->APB1ENR |= RCC_APB1ENR_USART2EN;
	//Transmit and receive enable
	USART2->CR1 |= USART_CR1_TE | USART_CR1_RE;
	// Enable DMA for receiver
	USART2->CR3 |= USART_CR3_DMAR;
	// Set baudrate
	USART2->BRR |= ((PERIPH_CLOCK1 + BAUDRATE/2) / BAUDRATE);

	// DMA
	RCC->AHBENR |= RCC_AHBENR_DMA1EN;
  // Memory increment, circular mode, transfer complete interrupt enable
	DMA1_Channel6->CCR |= DMA_CCR_MINC | DMA_CCR_CIRC | DMA_CCR_TCIE;
	NVIC_EnableIRQ(DMA1_Channel6_IRQn);
	// Set the peripheral address to be USART2->DR
	DMA1_Channel6->CPAR = (uint32_t)&USART2->DR;
	DMA1_Channel6->CMAR = (uint32_t)buffer;
	DMA1_Channel6->CNDTR = LENGTH;
	DMA1_Channel6->CCR |= DMA_CCR_EN;

	//Enable UART
	USART2->CR1 |= USART_CR1_UE;
}

void DMA1_Channel6_IRQHandler(void) {
  digitalWrite(LED, !digitalRead(LED));
	if(DMA1->ISR & DMA_ISR_TCIF6) {
		dataReady = 1;
		DMA1->IFCR = DMA_IFCR_CTCIF6;
	}
}

void setup() {
  DebugPort.begin(230400);
  delay(3000);
  DebugPort.println("ahoj");
  pinMode(LED, OUTPUT);
  initLD();
}

void loop() {
  DebugPort.println("x");
  delay(1000);
/*
  if (DMA1->ISR & DMA_ISR_HTIF6) {
 	  DMA1->IFCR = DMA_IFCR_CTCIF6 | DMA_IFCR_CHTIF6 | DMA_IFCR_CGIF6;
    digitalWrite(LED, !digitalRead(LED));
  }
*/  
}