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Problems using HPI8 port as general purpose I/O

Started by zektronix January 21, 2003
Hello.

I have a problem using the HPI8 port as GPIO in the c5409 DSP.
With the Spectrum Digital EVB sd5409 I had no problems using this
port. When I made my board, with a microcontroller connected to this
port, I'm not able to write anything, and the logic level of this 8
bit I/O port is low.
The pin configuration is:
CLKOUT, R/W#, MSTRB#, MSC#, HOLD#, HOLDA#, IAQ# left open
MP/MC# and HPIENA tied low
HCNTL0, HCNTL1, HBIL, HCS#, HDS1, HDS2#, HAS#, HR/W#, HRDY, HINT#,
HPI16 left open

When used as output, I set the GPIOCR as output (0x00ff) and put data
to GPIOSR, but I don't see anything to this port, just 0.
When used as input, I set the GPIOCR as input (0x0000) and read data
to GPIOSR, but I don't see anything to this port, just 0.

Where is the mistake? Somebody had the same problem, solved?

Another strange thing is related to the pin MP/MC#: when tied to 0, I
can dowload the SW via JTAG and run the program, whereas when MP/MC#
= 1 I see many error messages such as "data verification failed at
address 0x80" and other addresses, and the program is jammed. with
the evaluation module the download I never had this kind of problem.

Somebody else had the same behaviour?

Thanks.
Mario