uart.c
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/*
* Copyright (C) 2008-2015, Freie Universitaet Berlin
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
/**
* @ingroup cpu_lpc2387
* @{
*
* @file
* @brief Peripheral UART driver implementation
*
* @author Kaspar Schleiser <kaspar@schleiser.de>
* @author Heiko Will <hwill@inf.fu-berlin.de>
* @author Hauke Petersen <hauke.petersen@fu-berlin.de>
*
* @}
*/
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include "lpc23xx.h"
#include "VIC.h"
#include "periph/uart.h"
/* for now, we only support one UART device... */
static uart_rx_cb_t _rx_cb;
static void * _cb_arg;
void UART0_IRQHandler(void) __attribute__((interrupt("IRQ")));
int uart_init(uart_t dev, uint32_t baudrate, uart_rx_cb_t rx_cb, void *arg)
{
(void) baudrate;
/* for now, we only support one UART device and only the RX interrupt */
if (dev != 0) {
return UART_NODEV;
}
/* save interrupt context */
_rx_cb = rx_cb;
_cb_arg = arg;
/* power on the UART device */
PCONP |= PCUART0;
/* UART0 clock divider is CCLK/8 */
PCLKSEL0 |= BIT6 + BIT7;
/* configure to 8N1 */
U0LCR = 0x83;
/* Baudrate calculation:
* BR = PCLK (9 MHz) / (16 x 256 x DLM + DLL) x (1/(DIVADDVAL/MULVAL)) */
/* TODO: UART Baudrate calculation using the baudrate parameter */
U0FDR = 0x92; /* DIVADDVAL = 0010 = 2, MULVAL = 1001 = 9 */
U0DLM = 0x00;
U0DLL = 0x04;
U0LCR = 0x03; /* DLAB = 0 */
U0FCR = 0x07; /* Enable and reset TX and RX FIFO */
/* install and enable the IRQ handler */
install_irq(UART0_INT, UART0_IRQHandler, 6);
U0IER |= BIT0; /* enable only RX irq */
return UART_OK;
}
void uart_write(uart_t uart, const uint8_t *data, size_t len)
{
(void) uart;
for (size_t i = 0; i < len; i++) {
while (!(U0LSR & BIT5)) {}
U0THR = data[i];
}
}
void UART0_IRQHandler(void)
{
switch (U0IIR & UIIR_ID_MASK) {
case UIIR_CTI_INT: /* Character Timeout Indicator */
case UIIR_RDA_INT: /* Receive Data Available */
do {
uint8_t c = (uint8_t)U0RBR;
_rx_cb(_cb_arg, c);
} while (U0LSR & ULSR_RDR);
break;
default:
U0LSR;
U0RBR;
break;
}
VICVectAddr = 0; /* Acknowledge Interrupt */
}