MPC8241 and Wiggler - any hints?

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?

Reply to
Lewin A.R.W. Edwards
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snipped-for-privacy@larwe.com (Lewin A.R.W. Edwards) wrote in news: snipped-for-privacy@posting.google.com:

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

Reply to
Allan R. Batteiger

Hi Allan,

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.

Reply to
Lewin A.R.W. Edwards

Why I give you ask if you know the interface is basically supplying the right signals?

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.

What on earth are you talking about?

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Lady Chatterly

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