rt-thread/bsp/lpc122x/uart.c

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/****************************************************************************
* $Id:: uart.c 3736 2010-06-24 02:07:03Z usb00423 $
* Project: NXP LPC122x UART example
*
* Description:
* This file contains UART code example which include UART
* initialization, UART interrupt handler, and related APIs for
* UART access.
*
****************************************************************************
* Software that is described herein is for illustrative purposes only
* which provides customers with programming information regarding the
* products. This software is supplied "AS IS" without any warranties.
* NXP Semiconductors assumes no responsibility or liability for the
* use of the software, conveys no license or title under any patent,
* copyright, or mask work right to the product. NXP Semiconductors
* reserves the right to make changes in the software without
* notification. NXP Semiconductors also make no representation or
* warranty that such application will be suitable for the specified
* use without further testing or modification.
****************************************************************************/
#include <rthw.h>
#include <rtthread.h>
#include <CMSIS/LPC122x.h>
#include "uart.h"
#define IER_RBR 0x01
#define IER_THRE 0x02
#define IER_RLS 0x04
#define IIR_PEND 0x01
#define IIR_RLS 0x03
#define IIR_RDA 0x02
#define IIR_CTI 0x06
#define IIR_THRE 0x01
#define LSR_RDR 0x01
#define LSR_OE 0x02
#define LSR_PE 0x04
#define LSR_FE 0x08
#define LSR_BI 0x10
#define LSR_THRE 0x20
#define LSR_TEMT 0x40
#define LSR_RXFE 0x80
/**
* @addtogroup LPC11xx
*/
/*@{*/
#if defined(RT_USING_UART) && defined(RT_USING_DEVICE)
#define UART_BAUDRATE 115200
struct rt_uart_lpc
{
struct rt_device parent;
/* buffer for reception */
rt_uint8_t read_index, save_index;
rt_uint8_t rx_buffer[RT_UART_RX_BUFFER_SIZE];
}uart_device;
void UART0_IRQHandler(void)
{
rt_ubase_t level, iir;
struct rt_uart_lpc* uart = &uart_device;
/* read IIR and clear it */
iir = LPC_UART0->IIR;
iir >>= 0x01; /* skip pending bit in IIR */
iir &= 0x07; /* check bit 1~3, interrupt identification */
if (iir == IIR_RDA) /* Receive Line Status */
{
/* If no error on RLS, normal ready, save into the data buffer. */
/* Note: read RBR will clear the interrupt */
uart->rx_buffer[uart->save_index] = LPC_UART0->RBR;
level = rt_hw_interrupt_disable();
uart->save_index ++;
if (uart->save_index >= RT_UART_RX_BUFFER_SIZE)
uart->save_index = 0;
rt_hw_interrupt_enable(level);
/* invoke callback */
if(uart->parent.rx_indicate != RT_NULL)
{
rt_size_t length;
if (uart->read_index > uart->save_index)
length = RT_UART_RX_BUFFER_SIZE - uart->read_index + uart->save_index;
else
length = uart->save_index - uart->read_index;
uart->parent.rx_indicate(&uart->parent, length);
}
}
return;
}
/*****************************************************************************
** Function name: rt_uart_init
** Descriptions:
** parameters: dev
** Returned value: None
*****************************************************************************/
static rt_err_t rt_uart_init(rt_device_t dev)
{
rt_uint32_t Fdiv;
rt_uint32_t regVal;
NVIC_DisableIRQ(UART0_IRQn);
/* Init UART Hardware */
LPC_IOCON->PIO0_1 &= ~0x07; /* UART I/O config */
LPC_IOCON->PIO0_1 |= 0x02; /* UART RXD */
LPC_IOCON->PIO0_2 &= ~0x07;
LPC_IOCON->PIO0_2 |= 0x02; /* UART TXD */
/* Enable UART clock */
LPC_SYSCON->PRESETCTRL |= (0x1<<2);
LPC_SYSCON->SYSAHBCLKCTRL |= (0x1<<12);
LPC_SYSCON->UART0CLKDIV = 0x1; /* divided by 1 */
LPC_UART0->LCR = 0x83; /* 8 bits, no Parity, 1 Stop bit */
regVal = LPC_SYSCON->UART0CLKDIV;
Fdiv = ((SystemAHBFrequency/regVal)/16)/UART_BAUDRATE ; /*baud rate */
LPC_UART0->DLM = Fdiv / 256;
LPC_UART0->DLL = Fdiv % 256;
LPC_UART0->LCR = 0x03; /* DLAB = 0 */
LPC_UART0->FCR = 0x07; /* Enable and reset TX and RX FIFO. */
/* Read to clear the line status. */
regVal = LPC_UART0->LSR;
/* Ensure a clean start, no data in either TX or RX FIFO. */
while ( LPC_UART0->LSR & (LSR_THRE|LSR_TEMT) != (LSR_THRE|LSR_TEMT) );
while ( LPC_UART0->LSR & LSR_RDR )
{
regVal = LPC_UART0->RBR; /* Dump data from RX FIFO */
}
/* Enable the UART Interrupt */
NVIC_EnableIRQ(UART0_IRQn);
LPC_UART0->IER = IER_RBR | IER_THRE | IER_RLS; /* Enable UART interrupt */
return RT_EOK;
}
static rt_err_t rt_uart_open(rt_device_t dev, rt_uint16_t oflag)
{
RT_ASSERT(dev != RT_NULL);
if(dev->flag & RT_DEVICE_FLAG_INT_RX)
{
/* Enable the UART Interrupt */
NVIC_EnableIRQ(UART0_IRQn);
}
return RT_EOK;
}
static rt_err_t rt_uart_close(rt_device_t dev)
{
RT_ASSERT(dev != RT_NULL);
if (dev->flag & RT_DEVICE_FLAG_INT_RX)
{
/* Disable the UART Interrupt */
NVIC_DisableIRQ(UART0_IRQn);
}
return RT_EOK;
}
static rt_size_t rt_uart_read(rt_device_t dev, rt_off_t pos, void* buffer, rt_size_t size)
{
rt_uint8_t* ptr;
struct rt_uart_lpc *uart = (struct rt_uart_lpc*)dev;
RT_ASSERT(uart != RT_NULL);
/* point to buffer */
ptr = (rt_uint8_t*) buffer;
if (dev->flag & RT_DEVICE_FLAG_INT_RX)
{
while (size)
{
/* interrupt receive */
rt_base_t level;
/* disable interrupt */
level = rt_hw_interrupt_disable();
if (uart->read_index != uart->save_index)
{
*ptr = uart->rx_buffer[uart->read_index];
uart->read_index ++;
if (uart->read_index >= RT_UART_RX_BUFFER_SIZE)
uart->read_index = 0;
}
else
{
/* no data in rx buffer */
/* enable interrupt */
rt_hw_interrupt_enable(level);
break;
}
/* enable interrupt */
rt_hw_interrupt_enable(level);
ptr ++;
size --;
}
return (rt_uint32_t)ptr - (rt_uint32_t)buffer;
}
return 0;
}
static rt_size_t rt_uart_write(rt_device_t dev, rt_off_t pos, const void* buffer, rt_size_t size)
{
char *ptr;
ptr = (char*)buffer;
if (dev->flag & RT_DEVICE_FLAG_STREAM)
{
/* stream mode */
while (size)
{
if (*ptr == '\n')
{
/* THRE status, contain valid data */
while ( !(LPC_UART0->LSR & LSR_THRE) );
/* write data */
LPC_UART0->THR = '\r';
}
/* THRE status, contain valid data */
while ( !(LPC_UART0->LSR & LSR_THRE) );
/* write data */
LPC_UART0->THR = *ptr;
ptr ++;
size --;
}
}
else
{
while ( size != 0 )
{
/* THRE status, contain valid data */
while ( !(LPC_UART0->LSR & LSR_THRE) );
/* write data */
LPC_UART0->THR = *ptr;
ptr++;
size--;
}
}
return (rt_size_t) ptr - (rt_size_t) buffer;
}
void rt_hw_uart_init(void)
{
struct rt_uart_lpc* uart;
/* get uart device */
uart = &uart_device;
/* device initialization */
uart->parent.type = RT_Device_Class_Char;
rt_memset(uart->rx_buffer, 0, sizeof(uart->rx_buffer));
uart->read_index = uart->save_index = 0;
/* device interface */
uart->parent.init = rt_uart_init;
uart->parent.open = rt_uart_open;
uart->parent.close = rt_uart_close;
uart->parent.read = rt_uart_read;
uart->parent.write = rt_uart_write;
uart->parent.control = RT_NULL;
uart->parent.user_data = RT_NULL;
rt_device_register(&uart->parent,
"uart", RT_DEVICE_FLAG_RDWR | RT_DEVICE_FLAG_STREAM | RT_DEVICE_FLAG_INT_RX);
}
#endif
/******************************************************************************
** End Of File
******************************************************************************/