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
Copyright © 1988-2008 OAR Corporation