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127 lines
2.7 KiB
C
127 lines
2.7 KiB
C
/*
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* uart.c - Implementation for the TelosB UART
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* Copyright (C) 2013 Oliver Hahm <oliver.hahm@inria.fr>
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*
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* This file is subject to the terms and conditions of the GNU Lesser
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* General Public License v2.1. See the file LICENSE in the top level
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* directory for more details.
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*/
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#include <stdio.h>
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#include <stdint.h>
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#include "cpu.h"
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#include "board.h"
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#include "kernel.h"
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#include "board_uart0.h"
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#define UART1_TX U1TXBUF
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#define UART1_WAIT_TXDONE() while ( (U1TCTL & TXEPT) == 0 ) { _NOP(); }
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#define BAUDRATE (115200ul)
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static uint8_t calc_umctl(uint16_t br)
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{
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/* from TI slaa049 */
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register uint8_t CMOD = 256 * br - 256 * (br + 1) / 2;
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register uint8_t c = 0;
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register int i = 0;
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register uint8_t a = CMOD;
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a <<= 1;
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do {
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if (a & 0x80) { /* Overflow to integer? */
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a = a - 128 + CMOD; /* Yes, subtract 1.000000 */
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c |= 0x80;
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}
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else {
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a += CMOD; /* No, add fraction */
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}
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if (i == 7) {
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return c;
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}
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i++;
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c >>= 1;
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}
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while (1);
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}
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void uart_init(void)
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{
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UCTL1 = SWRST; /* hold UART1 module in reset */
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UCTL1 |= CHAR; /* 8-bit character */
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/* 115200 baud, clocked from 4.8MHz SMCLK */
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UTCTL1 |= SSEL1; /* UCLK = SCLK */
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UBR01 = F_CPU / BAUDRATE;
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UBR11 = (F_CPU / BAUDRATE) >> 8;
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UMCTL1 = calc_umctl(F_CPU / BAUDRATE); /* set modulation */
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ME2 |= UTXE1 + URXE1; /* enable UART1 TX/RX */
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UCTL1 &= ~SWRST; /* clear UART1 reset bit */
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IE2 |= URXIE1; /* enable rx interrupt */
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IFG1 &= ~UTXIFG1;
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}
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int putchar(int c)
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{
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UART1_TX = c;
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UART1_WAIT_TXDONE();
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return c;
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}
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int getchar(void)
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{
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#ifdef MODULE_UART0
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return uart0_readc();
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#else
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return U1RXBUF;
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#endif
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}
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uint8_t uart_readByte(void)
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{
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return U1RXBUF;
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}
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void usart1irq(void);
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/**
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* \brief the interrupt function
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*/
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void __attribute__((interrupt(USART1RX_VECTOR))) usart1irq(void)
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{
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/* Check status register for receive errors. */
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if (U1RCTL & RXERR) {
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if (U1RCTL & FE) {
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puts("rx framing error");
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}
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if (U1RCTL & OE) {
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puts("rx overrun error");
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}
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if (U1RCTL & PE) {
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puts("rx parity error");
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}
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if (U1RCTL & BRK) {
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puts("rx break error");
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}
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/* Clear error flags by forcing a dummy read. */
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volatile int c = U1RXBUF;
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(void) c;
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}
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#ifdef MODULE_UART0
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else if (uart0_handler_pid != KERNEL_PID_UNDEF) {
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volatile int c = U1RXBUF;
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uart0_handle_incoming(c);
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uart0_notify_thread();
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}
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#endif
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}
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