Weird EDMA interrupt problem with TMS320C6416 TEB

Started by cytan299 March 6, 2003
Hi all,
I have a really weird problem with the TMS30C6416 TEB when I do
DMA with EXT INT 4. If the TMS320C6416 is connected
like this:

TMS320C6416 ------>-----
EXT INT 4 pin |
|- pushbutton switch

and the pushbutton switch is pushed and released, the CIPR bit 4 is
set and my EDMA code is executed and everything is OK. Note that
EXT4 pin is internally pulled high by a resistor in the TMS320C6416
chip. And the EDMA code is programmed for edge triggered from low to
high. Of course, I don't expect a clean edged pulse since the
pushbutton switch is not debounced.

However, if I connect as follows:
TMS320C6416 ----->---- +3.3V pulse _| |_
EXT INT 4 pin The CIPR bit 4 is NOT set unless I send a few of these 3.3V pulses.
Why am I missing these nice clean 3.3V pulses (width 500ns long
which is > 4x clock freq) ?

Does running this in the XDS510PP emulator screw up external

Is there anything else in my code which needs to be set?
I'll supply the source if required.

Thanks for any help.