Keil MCB251, Руководство пользователя

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MCB251 Evaluation Board User’s Guide 47
/*-----------------------------------------------
This function performs a general initialization of
the external UART on the MCB251.
-----------------------------------------------*/
void extsio_setup (
unsigned long baudrate)
{
unsigned char dummy;
extsio_baudrate (baudrate);
*EXTSIO_LCR = 0x03; /* 8-bit, 1 stop, no parity */
*EXTSIO_IER = 0x00; /* disable all interrupts */
*EXTSIO_MCR = 0x00;
dummy = *EXTSIO_LSR;
dummy = *EXTSIO_MSR;
dummy = *EXTSIO_RBR;
}
/*-----------------------------------------------
Send a character out the external UART.
-----------------------------------------------*/
void extsio_putchar (
unsigned char c)
{
while ((*EXTSIO_LSR & 0x20) == 0);
*EXTSIO_THR = c;
}
/*-----------------------------------------------
Receive a character from the external UART. If
no characters have been received, -1 is returned.
-----------------------------------------------*/
int extsio_getchar (void)
{
if (*EXTSIO_LSR & 0x01)
return ((unsigned) *EXTSIO_RBR);
return (-1);
}
/*-----------------------------------------------
_getkey replacement for external UART.
-----------------------------------------------*/
char _getkey (void)
{
int c;
while ((c = extsio_getchar ()) == -1);
return (c);
}