Lingbo-
> Which 55x DSP are you using?
>
> We always use multiplexed mode for HPI. However, for non-multiplexed mode
> I think
> you still need to connect HCNTL1, which is not in your list above. Both
> HCNTL0 and
> HCNTL1 have to be connected to allow access to four (4) possible HPI
> registers:
>
> -HPIC
> -HPIA
> -HPID no autoincrement
> -HPID autoincrement
>
> In the C5502 data sheet, Figure 3-5 shows both HCNTLx connected for
> non-multiplexed
> HPI. If you're not using 5502, then possibly look for a similar figure in
> other 55x
> data sheets.
>
> Also, do you have HPIENA active? What about pull-up/down Rs on GPIOx
> lines that
> select HPI mode at Reset?
>
> -Jeff
>
> Hi,Jeff,
> I'm using 5510 v2.2,which is not supporting multiplexed mode for HPI anymore.In
> non-multiplexed mode,HCNTL1 is used as HA1(ADDRESS 1).Only HCNTL0 is configured to
> selecte the HPID/HPIC register.
> There may be lots of differences between 5510 and 5502. I can not find any pin
> named HPIENA.
> DSP is powered up with BOOTM[3:0] = 1101,which selects the EHPI Boot Mode .Each
> GPIO of these is pulled up/down by a 10K Rs.
> Thank you for your email.

Ok 5510 and not 5502. Then your hook-up may be Ok. Are you sure 10k is strong
enough value for pull-up/down Rs? You might check the data sheet closely. Sometimes
TI recommends stronger value, such as 1k.

One debug suggestion -- read HPIC first. That's a known value, so it's easier to
test. Then run some small DSP code (via JTAG) that sets HINT bit, and verify you can
read the 1 bit change. If your HPI circuit doesn't allow you to read, then obviously
you can't write.

-Jeff

PS. Please post to the group, not to me. Start a New Thread