uart.c
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/*
* Copyright (C) 2015 Freie Universität 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_lpc11u34
* @{
*
* @file
* @brief Implementation of the low-level UART driver for the LPC11U34
*
* @author Paul RATHGEB <paul.rathgeb@skynet.be>
* @}
*/
#include "cpu.h"
#include "periph/uart.h"
/**
* @brief UART device configurations
*/
static uart_isr_ctx_t config[UART_NUMOF];
/**
* @todo Merge with uart_init()
*/
static int init_base(uart_t uart, uint32_t baudrate);
int uart_init(uart_t uart, uint32_t baudrate, uart_rx_cb_t rx_cb, void *arg)
{
int res = init_base(uart, baudrate);
if (res != UART_OK) {
return res;
}
/* save callbacks */
config[uart].rx_cb = rx_cb;
config[uart].arg = arg;
switch (uart) {
#if UART_0_EN
case UART_0:
/* configure and enable global device interrupts */
NVIC_SetPriority(UART_0_IRQ, UART_IRQ_PRIO);
NVIC_EnableIRQ(UART_0_IRQ);
/* enable RX interrupt */
UART_0_DEV->IER |= (1 << 0);
break;
#endif
}
return UART_OK;
}
static int init_base(uart_t uart, uint32_t baudrate)
{
switch (uart) {
#if UART_0_EN
case UART_0:
/* this implementation only supports 115200 baud */
if (baudrate != 115200) {
return UART_NOBAUD;
}
/* select and configure the pin for RX */
UART_0_RX_PINSEL &= ~0x07;
UART_0_RX_PINSEL |= (UART_0_AF);
/* select and configure the pin for TX */
UART_0_TX_PINSEL &= ~0x07;
UART_0_TX_PINSEL |= (UART_0_AF);
/* power on UART device and select peripheral clock */
UART_0_CLKEN();
UART_0_CLKSEL();
/* set mode to 8N1 and enable access to divisor latch */
UART_0_DEV->LCR = ((0x3 << 0) | (1 << 7)) | (3 << 4);
/* set baud rate registers (fixed for now) */
UART_0_DEV->DLM = 0;
UART_0_DEV->DLL = 17;
UART_0_DEV->FDR |= (8) | (15 << 4);
/* disable access to divisor latch */
UART_0_DEV->LCR &= ~0x80;
/* enable FIFOs */
UART_0_DEV->FCR = (1 << 0) | (1 << 1) | (1 << 2) | (2 << 6);
break;
#endif
default:
return UART_NODEV;
}
return UART_OK;
}
void uart_write(uart_t uart, const uint8_t *data, size_t len)
{
if (uart == UART_0) {
for (size_t i = 0; i < len; i++) {
while (!(UART_0_DEV->LSR & (1 << 5)));
UART_0_DEV->THR = data[i];
}
}
}
void uart_poweron(uart_t uart)
{
switch (uart) {
#if UART_0_EN
case UART_0:
UART_0_CLKEN();
break;
#endif
}
}
void uart_poweroff(uart_t uart)
{
switch (uart) {
#if UART_0_EN
case UART_0:
UART_0_CLKDIS();
break;
#endif
}
}
#if UART_0_EN
void UART_0_ISR(void)
{
if (UART_0_DEV->LSR & (1 << 0)) { /* is RDR flag set? */
uint8_t data = (uint8_t)UART_0_DEV->RBR;
config[UART_0].rx_cb(config[UART_0].arg, data);
}
cortexm_isr_end();
}
#endif