I haven't dug into you rparticular application, but the ICD2 protocol
does depend, in some part, on the chip's oscillator.

You should be able to disable the ICD2 as a debugger, enable it as a
programmer, and then do a mass erase on the chip.

Let us know how it goes.

-Adam

On 5/21/08, Electron <electron2k4@infinito.it> wrote:
>
> Hello,
> I made a board with a dsPIC30F5011 20I/PTG 043540G (the chip is revision mg3 a1, probably an engineering sample, I have some tens of them I'd like to use for prototypes).
> All worked ok until I made it execute this code sequence (I wanted to see if LP 32.768KHz clock could be slowed down):
>
>                mov.b   #0x00,w0                ; value to put into OSCCONH
>                mov     #OSCCONH,w1
>                mov.b   #0x78,w2
>                mov.b   #0x9A,w3
>                mov.b   w2,[w1]
>                mov.b   w3,[w1]
>                mov.b   w0,[w1]
>                mov.b   #0x42,w0                ; value to put into OSCCONL
>                mov     #OSCCONL,w1
>                mov.b   #0x46,w2
>                mov.b   #0x57,w3
>                mov.b   w2,[w1]
>                mov.b   w3,[w1]
>                mov.b   w0,[w1]
>
> Well, since I wrote 0x42 to OSCCONL, I cannot communicate with the dsPIC via MPLAB ICD2 anymore.
>
> The o'scope shows the chip works good (the firmware makes a pin toggle), but it now doesn't communicate with the ICD2 anymore.
>
> What can I do, short of desoldering the chip and placing a new one in its place?
>
> But how can a stupid software instruction turn a chip into deafness?
>
> Thanks.
> --
> Electron
>
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