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MPC8241 and Wiggler - any hints?

Started by Lewin A.R.W. Edwards November 13, 2004
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?
larwe@larwe.com (Lewin A.R.W. Edwards) wrote in 
news:608b6569.0411130932.280e759f@posting.google.com:

> 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? >
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
Hi Allan,

> 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
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.
In article <608b6569.0411130932.280e759f@posting.google.com> larwe@larwe.com (Lewin A.R.W. Edwards) wrote:
> >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.
Why I give you ask if you 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.
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>There is
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