uart.c

来自「一个基于ARM9的操作系统, 实现了很多的功能,包括内存管理,进程创建等」· C语言 代码 · 共 39 行

/*
* file:
*       uart.c
* description:
*       uart controller code.
*/

void uart_ctrl_init(unsigned long pclk, int baudrate)
{
    int i;

    /* enable uart rx0/tx0 */
    rPCONE &= ~(0x0f<<2);
    rPCONE |= (0x0a<<2);
    rPUPE  |= (0x03<<1);

    rUFCON0  = 0x0;
    rUMCON0  = 0x0;
    rULCON0  = 0x3;
    rUBRDIV0 = (unsigned int)((pclk/(baudrate*16.0f) + 0.5f) - 1);
    rUCON0   = 0x5;

    for(i=0; i<100; i++);
}


int uart_ctrl_putchar(int c)
{
    /* wait until THR is empty. */
    while(!(rUTRSTAT0 & 0x2))
        /* nop */;
    rUTXH0 = (unsigned char)c;

    return c;
}


/* end of file */