[U-Boot-Users] How To Register Interrupt Routines in ARM920T?

Rodel Miguel rodelfmiguel at gmail.com
Wed Dec 8 07:41:33 CET 2004

Hi All,

I am porting U-Boot to a custom board (ARM920T) and I have to do
something about the UART (ns16550.c) driver to support (I know WD
would disagree with this :p) XON/XOFF.  I have to do this because my
board can support only < 19200 baudrates.  At 19200 baudrate, I have a
functional serial console but downloading binaries using loadb, kermit
would always say that the remote host is not reponding (ERROR: Remote
Kermit Not Responding).  I debugged this on the getc level and
verified that my board's U-Boot can accept the first few data from my
PC's kermit and then the loadb function hangs, i.e. does not accept
any data.  I think this is because my UART's FIFO is not handled well,
and probably needs software flow control.

How do I register my interrupt routine that would send XOFF data to
the PC's kermit whenever an UART trigger (probably when RXRDY pin from
NS16550 becomes LOW) occurs.  The trigger is of course asserted when
the FIFO buffer reaches a certain threshold.  I saw the interrupt.c
implementation in cpu/arm920t/ but didn't get the information I was
looking for, i.e. registering my interrupt routine.  Please help me
with this.

Thank you very much for your time.

Best Regards,

Rodel Miguel

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