uart.c
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/*
* Copyright (C) 2015 Rakendra Thapa <rakendrathapa@gmail.com>
*
* 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_lm4f120
* @{
*
* @file uart.c
* @brief Implementation of the low-level UART driver for the LM4F120
*
* @author Rakendra Thapa <rakendrathapa@gmail.com>
*
* @}
*/
#include <stdint.h>
#include "assert.h"
#include "cpu.h"
#include "periph/uart.h"
#include "periph_conf.h"
/**
* @brief UART device configurations
*/
static uart_isr_ctx_t config[UART_NUMOF];
static int init_base(uart_t uart, uint32_t baudrate);
/**
* Configuring the UART console
*/
int uart_init(uart_t uart, uint32_t baudrate, uart_rx_cb_t rx_cb, void *arg)
{
/* Check the arguments */
assert(uart == 0);
/* Check to make sure the UART peripheral is present */
if(!ROM_SysCtlPeripheralPresent(SYSCTL_PERIPH_UART0)){
return UART_NODEV;
}
int res = init_base(uart, baudrate);
if(res != UART_OK){
return res;
}
/* save callbacks */
config[uart].rx_cb = rx_cb;
config[uart].arg = arg;
/* ulBase = g_ulUARTBase[uart]; */
switch (uart){
#if UART_0_EN
case UART_0:
ROM_UARTTxIntModeSet(UART0_BASE, UART_TXINT_MODE_EOT);
ROM_UARTFIFOLevelSet(UART0_BASE, UART_FIFO_TX4_8, UART_FIFO_RX4_8);
ROM_UARTFIFOEnable(UART0_BASE);
/* Enable the UART interrupt */
NVIC_EnableIRQ(UART_0_IRQ_CHAN);
/* Enable RX interrupt */
UART0_IM_R = UART_IM_RXIM | UART_IM_RTIM;
break;
#endif
#if UART_1_EN
case UART_1:
/* Enable the UART interrupt */
NVIC_EnableIRQ(UART_1_IRQ_CHAN);
break;
#endif
}
return UART_OK;
}
static int init_base(uart_t uart, uint32_t baudrate)
{
switch(uart){
#if UART_0_EN
case UART_0:
ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);
ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);
ROM_GPIOPinConfigure(GPIO_PA0_U0RX);
ROM_GPIOPinConfigure(GPIO_PA1_U0TX);
ROM_GPIOPinTypeUART(GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1);
ROM_UARTDisable(UART0_BASE);
ROM_UARTConfigSetExpClk(UART0_BASE,ROM_SysCtlClockGet(), baudrate,
(UART_CONFIG_PAR_NONE | UART_CONFIG_STOP_ONE |
UART_CONFIG_WLEN_8));
ROM_UARTEnable(UART0_BASE);
break;
#endif
default:
return UART_NODEV;
}
return UART_OK;
}
void uart_write(uart_t uart, const uint8_t *data, size_t len)
{
for (size_t i = 0; i < len; i++) {
ROM_UARTCharPut(UART0_BASE, (char)data[i]);
}
}
void uart_poweron(uart_t uart)
{
ROM_UARTEnable(UART0_BASE);
}
void uart_poweroff(uart_t uart)
{
ROM_UARTDisable(UART0_BASE);
}
/**
* The UART interrupt handler.
*/
void isr_uart0(void)
{
unsigned long ulStatus;
ulStatus = ROM_UARTIntStatus(UART0_BASE, true);
ROM_UARTIntClear(UART0_BASE, ulStatus);
/* Are we interrupted due to a recieved character */
if(ulStatus & (UART_INT_RX | UART_INT_RT))
{
while(ROM_UARTCharsAvail(UART0_BASE))
{
long lchar = ROM_UARTCharGetNonBlocking(UART0_BASE);
config[UART_0].rx_cb(config[UART_0].arg, (uint8_t)lchar);
}
}
cortexm_isr_end();
}