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#ifndef __USART_H__
#define __USART_H__
#include "types.h"
#include "devices.h"
#include "string.h"
// baudrate clock divisors
// values from TL16C550C datasheet (table 9 for 1.8432 MHz crystal)
#define USART_BAUDRATE_50 2304
#define USART_BAUDRATE_75 1536
#define USART_BAUDRATE_110 1047
#define USART_BAUDRATE_134_5 857
#define USART_BAUDRATE_150 768
#define USART_BAUDRATE_300 384
#define USART_BAUDRATE_600 192
#define USART_BAUDRATE_1200 96
#define USART_BAUDRATE_1800 64
#define USART_BAUDRATE_2000 58
#define USART_BAUDRATE_2400 48
#define USART_BAUDRATE_3600 32
#define USART_BAUDRATE_4800 24
#define USART_BAUDRATE_7200 16
#define USART_BAUDRATE_9600 12
#define USART_BAUDRATE_19200 6
#define USART_BAUDRATE_38400 3
#define USART_BAUDRATE_56000 3
// parity
#define USART_PARITY_NONE 0
#define USART_PARITY_EVEN 1
#define USART_PARITY_ODD 2
// stop bits
#define USART_STOP_BITS_1 10
#define USART_STOP_BITS_15 15
#define USART_STOP_BITS_2 20
// word lenght
#define USART_WORD_LENGTH_5 0
#define USART_WORD_LENGTH_6 1
#define USART_WORD_LENGTH_7 2
#define USART_WORD_LENGTH_8 3
// autoflow
#define USART_AUTOFLOW_ALL 3
#define USART_AUTOFLOW_CTS 2
#define USART_AUTOFLOW_OFF 0
/* this structure is only for internal usage */
struct _usart_device
{
register_t buffer; // also used as LSB for divisor latch
struct IER
{
volatile int received_data_interrupt :1;
volatile int transmitter_empty_interrupt :1;
volatile int receiver_line_status_interrupt :1;
volatile int modem_status_interrupt :1;
volatile int reserved :4;
} IER;
struct IIR
{
volatile int interrupt_pending :1;
volatile int interrupt_id :3;
volatile int reserved :2;
volatile int fifos :2;
} IIR;
struct FCR
{
volatile int fifo_enable :1;
volatile int receiver_fifo_rst :1;
volatile int trasmitter_fifo_rst :1;
volatile int dma_mode_select :1;
volatile int reserved :1;
volatile int receiver_trigger :2;
} FCR;
struct LCR
{
volatile int word_length :2;
volatile int stop_bits :1;
volatile int parity :1;
volatile int even_parity :1;
volatile int stick_parity :1;
volatile int break_control :1;
volatile int divisor_latch_access :1;
} LCR;
struct MCR
{
volatile int data_terminal_ready :1;
volatile int request_to_send :1;
volatile int out1;
volatile int out2;
volatile int loop;
volatile int autoflow :1;
volatile int reserved :2;
} MCR;
struct LSR
{
volatile int data_ready :1;
volatile int overrun_error :1;
volatile int parity_error :1;
volatile int framing_error :1;
volatile int break_interrupt :1;
volatile int transmitter_holder_empty :1;
volatile int transmitter_empty :1;
volatile int fifo_recv_error :1;
} LSR;
struct MSR
{
volatile int delta_cts :1;
volatile int delta_data_set_ready :1;
volatile int trailing_edge_ring_indicator :1;
volatile int delta_data_carrier_detect :1;
volatile int clear_to_send :1;
volatile int data_set_ready :1;
volatile int ring_indicator :1;
volatile int data_carrier_detect :1;
} MSR;
register_t scratch;
};
// setup functions (wrappers)
void usart_set_baudrate(uint16_t baudrate);
void usart_set_parity(int mode);
void usart_set_stob_bits(int count);
void usart_set_word_length(int length);
void usart_set_autoflow(int mode);
inline void usart_init(uint16_t baudrate, int parity, int stop_bits);
void usart_transmit(uint8_t data);
uint8_t usart_receive();
int usart_write(uint8_t *data, size_t size);
int usart_read(uint8_t *buffer, size_t count);
#endif // __USART__H__
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