BSP and Device Driver Development Guide
The InterruptWrite is responsible for telling the UART
that the len characters at buf are to be transmitted.
static int InterruptWrite(int minor, const char *buf, int len)
{
tell the UART to transmit len characters from buf
return 0
}
The driver has to put the n first buf characters in the UART channel minor buffer (n is the UART channel size, n=1 on the MC68640). Generally, an interrupt is raised after these n characters being transmitted. So UART interrupts may have to be enabled after putting the characters in the UART.
BSP and Device Driver Development Guide
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