MPC8241 and Wiggler - any hints?

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Ah, Saturday. Time to sit down and play with this PowerPC board. I
installed a series resistor so the COP port on the board is supplying
IO power (3.3V) and fired everything up. But Commander gives me the
dreaded 03; cable disconnected error. If I query registers, I get
either all 0s or all 1s (randomly, it seems).

The only thing I can do is reset - that DOES work, so I know the
interface is basically supplying the right signals.

There is a jumper on the Wiggler board with RD and WR positions; I've
tried shorting both and neither way makes a difference.

There is also space on the target board for pullup resistors on four
of the COP port pins; are these required?

Re: MPC8241 and Wiggler - any hints?
snipped-for-privacy@larwe.com (Lewin A.R.W. Edwards) wrote in

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Try dropping the speed of the wriggler way down. The range is 1 to 8.
if you try 8 go get a cup of coffee between commands.  If reset works I
am told the JTAG/COP is working.  I have seen the same type of problems
on my 8260.  The answer was to drop the speed untill I could read / write
to memory reliably.  My speed ended up being 4.


Allan

Re: MPC8241 and Wiggler - any hints?
Hi Allan,

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Hey, thanks - that suggestion was on the money. I find that at a setting
of 5 I can read registers and flash but not RAM. Strange, I wonder if
this means that SDRAM refresh is stopped while the BDM interface is
working (that sounds pretty screwed up if it's true).

I didn't install a resistor pack on the empty space yet, mainly because
I don't know what values ought to go there (and a secondary issue being
that I don't have any 0603 packs - I'll have to find a board to scrounge
it off). Maybe that will improve my results.


Re: MPC8241 and Wiggler - any hints?
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Why I give you ask if you know the interface is basically supplying
the right signals?

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Women like to wear their hair longer and men have it much shorter.
Both sexes shave it all off when they're in active military service.

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What on earth are you talking about?

--
Lady Chatterly

"So KK (he is almost smart enough to get his 3rd K) tell everyone what
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