uart.c

/*
 * File      : board.c
 * This file is part of RT-Thread RTOS
 * COPYRIGHT (C) 2009 RT-Thread Develop Team
 *
 * The license and distribution terms for this file may be
 * found in the file LICENSE in this distribution or at
 * http://www.rt-thread.org/license/LICENSE
 *
 * Change Logs:
 * Date                Author       Notes
 * 2010-03-08     Bernard      The first version for LPC17xx
 * 2010-04-10     fify             Modified for M16C
*/

#include <rthw.h>
#include <rtthread.h>
#include "iom16c62p.h"
#include "bsp.h"
#include "uart.h"

#if defined(RT_USING_UART0) && defined(RT_USING_DEVICE)

struct rt_uart_m16c
{
	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  u0rec_handler(void)
{
	rt_ubase_t level;
	rt_uint8_t	 c;

    struct rt_uart_m16c* uart = &uart_device;

	while(ri_u0c1 == 0)
		;
	c = (char) u0rb;

	/* Receive Data Available */
    uart->rx_buffer[uart->save_index] = c;

    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);
	}
}

static rt_err_t rt_uart_init (rt_device_t dev)
{
    rt_uint32_t level;
    /* set UART0 bit rate generator bit rate can be calculated by:
          bit rate = ((BRG count source / 16)/baud rate) - 1
          Baud rate is based on main crystal or PLL not CPU core clock */
	//pclk1 = 1;   /// seleck F1SIO
    u0brg = (unsigned char)(((CPU_CLK_FREQ/16)/BAUD_RATE)-1);   //(N+1)

    /* UART Transmit/Receive Control Register 2 */
    ucon = 0x00;
         /*   00000000
          b0    U0IRS       UART0 transmit irq cause select bit, 0 = transmit buffer empty
          b1    U1IRS       UART1 transmit irq cause select bit, 0 = transmit buffer empty
          b2    U0RRM       UART0 continuous receive mode enable bit, set to 0 in UART mode
          b3    U1RRM       UART1 continuous receive mode enable bit, set to 0 in UART mode
          b4    CLKMD0      CLK/CLKS select bit 0, set to 0 in UART mode
          b5    CLKMD1      CLK/CLKS select bit 1, set to 0 in UART mode
          b6    RCSP        Separate CTS/RTS bit,
          b7    Reserved, set to 0 */

    /* UART0 transmit/receive control register 0 */
    /* f1 count source, CTS/RTS disabled, CMOS output */
    u0c0 = 0x10;
         /* 00010000
          b1:b0 CLK01:CLK0  BRG count source select bits                        //01         F8SIO
          b2    CRS         CTS/RTS function select bit
          b3    TXEPT       Transmit register empty flag
          b4    CRD         CTS/RTS disable bit
          b5    NCH         Data output select bit
          b6    CKPOL       CLK polarity select bit,set to 0 in UART mode
          b7    UFORM       Transfer format select bit,set to 0 in UART mode */

    /* UART0 transmit/receive control register 1 */
    /*  disable transmit and receive, no error output pin, data not inverted */
    u0c1 = 0x00;
         /*  00000000
          b0    TE          Transmit enable bit
          b1    TI          Transmit buffer empty flag
          b2    RE          Receive enable bit
          b3    RI          Receive complete flag
          b5:b4             Reserved, set to 0
          b6    UOLCH       Data logic select bit
          b7    UOERE       Error signal output enable bit */

    /* UART0 transmit/receive mode register */
    /* 8-bit data,asynch mode, internal clock, 1 stop bit, no parity */
    u0mr = 0x05;
         /*  00000101
          b2:b0 SMD12:SMD1  Serial I/O Mode select bits
          b3    CKDIR       Internal/External clock select bit, CKDIR
          b4    STPS        Stop bit length select bit, STPS
          b5    PRY         Odd/even parity select bit, PRY
          b6    PRYE        Parity enable bit, PRYE
          b7    IOPOL       TxD, RxD I/O polarity reverse bit */

    /* clear UART0 receive buffer by reading */
    u0tb = u0rb;
    /* clear UART0 transmit buffer */
    u0tb = 0;

    /* disable irqs before setting irq registers */
    level = rt_hw_interrupt_disable();
    /* Enable UART0 receive interrupt, priority level 4 */
    s0ric = 0x04;
    /* Enable all interrupts */
    rt_hw_interrupt_enable(level);

    /* UART0 transmit/receive control register 1 */
    /* enable transmit and receive */
    u0c1 = 0x05;
        /*  00000101    enable transmit and receive
        b0      TE          Transmit enable bit
        b1      TI          Transmit buffer empty flag
        b2      RE          Receive enable bit
        b3      RI          Receive complete flag
        b5:b4               Reserved, set to 0
        b6      UOLCH       Data logic select bit
        b7      UOERE       Error signal output enable bit */

	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 */
	}

	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 */
	}

	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_m16c *uart = (struct rt_uart_m16c*)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')
			{
			  while(ti_u0c1 == 0)
			    ;
			  u0tb = '\r';
			}

			/* THRE status, contain valid data */
			  while(ti_u0c1 == 0)
			    ;
			  u0tb = *ptr;
  
			ptr ++;
			size --;
		}
	}
	else
	{
		while ( size != 0 )
		{
			/* THRE status, contain valid data */
		  while(ti_u0c1 == 0)
		    ;
		  u0tb = *ptr;
	
			ptr++;
			size--;
		}
	}

	return (rt_size_t) ptr - (rt_size_t) buffer;
}

void rt_hw_uart_init(void)
{
	struct rt_uart_m16c* 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,
		"uart0", RT_DEVICE_FLAG_RDWR | RT_DEVICE_FLAG_STREAM | RT_DEVICE_FLAG_INT_RX);
}
#endif /* end of UART */

/*@}*/