#ifndef USART_H_
#define USART_H_

#include <inttypes.h>

struct usart {
  volatile uint32_t SR;   // Status register
  volatile uint32_t DR;   // Data register
  volatile uint32_t BRR;  // Baud rate register
  volatile uint32_t CR1;  // Control register 1
  volatile uint32_t CR2;  // Control register 2
  volatile uint32_t CR3;  // Control register 3
  volatile uint32_t GTPR; // Guard time and prescaler registe
};

#define USART2_BASE_ADDR (0x40004400U)
#define USART2 ((struct usart *) USART2_BASE_ADDR)

// SR Register
// Transmission data register empty
#define USART_SR_TXE_BIT 7
#define USART_SR_TXE_TRANSMITTED (1 << USART_SR_TXE_BIT)

// Read data register not empty
#define USART_SR_RXNE_BIT 5
#define USART_SR_RXNE_READY (1 <<USART_SR_RXNE_BIT)

// CR Register
// Oversampling mode
#define USART_CR1_OVER8_BIT 15
#define USART_CR1_OVER8_8 (1 << USART_CR1_OVER8_BIT)

// USART enable
#define USART_CR1_UE_BIT 13
#define USART_CR1_UE_ENABLE (1 << USART_CR1_UE_BIT)

// Trasmitter enable
#define USART_CR1_TE_BIT 3
#define USART_CR1_TE_ENABLE (1 << USART_CR1_TE_BIT)

// Receiver enable
#define USART_CR1_RE_BIT 2
#define USART_CR1_RE_ENABLE (1 << USART_CR1_RE_BIT)

// BRR Register
#define USART_BRR_MANTISSA_BIT 4 // Bits [15:4]
#define USART_BRR_MANTISSA_MASK (0b111111111111) // Bits [15:4]

#define USART_BRR_FRACTION_BIT 0 // Bits [3:0]
#define USART_BRR_FRACTION_MASK (0b111) // Bits [3:0]

void usart2_init(void);
void usart2_start(void);

void usart2_write_byte(char byte);

#endif