Flash swapped address line.

[Ken Kelly]

Terry,

	Here is the code to swap the address lines in VB6. PCMin is the input array,
PCMout is the output array.

   Dim index1, index2, j As Long
    index1 = 0
     Do While index1 < LengthF  ' Loop until end of file
     'swap A1 and A13
     j = index1 And &HDFFD
     If (index1 And &H2000) > 1 Then j = j + &H2
      If (index1 And &H2) > 1 Then j = j + &H2000
      'swap A2 and A12
     j = j And &HEFFB
     If (index1 And &H1000) > 1 Then j = j + &H4
      If (index1 And &H4) > 1 Then j = j + &H1000
      'swap A3 and A11
     j = j And &HF7F7
     If (index1 And &H800) > 1 Then j = j + &H8
      If (index1 And &H8) > 1 Then j = j + &H800
         
        PCMout(j) = PCMin(index1) 'Read next char
        index1 = index1 + 1 ' increment position in file
     Loop
     PCMin = PCMout

		Ken

TK wrote:
> 
> Thanks for the info. I think I am just over complicating the issue. I'll
> check out the Intel application note.
> 
> Terry Kelley
> -----Original Message-----
> From: Ward <wspoonemore at excite.com>
> To: gmecm at efi332.eng.ohio-state.edu <gmecm at efi332.eng.ohio-state.edu>
> Date: Sunday, June 27, 1999 1:05 PM
> Subject: Re: Flash swapped address line.
> 
> >If your research the Intel ap notes on the 512 Flash chip you will find the
> >recomended "twisting" of the address lines to help a "noise" problem> I
> >think these were the frist large scale production of theses chips.
> >
> >Orignialy I bugged them out from the CPU address pins. Then I wrote a small
> >application to un-twist them, after learing to down load and up load them,
> >the de-solder techneque quickly fell in to diss-use.
> >
> >Ward
> >
> >Ward
> >
> >On Sun, 27 Jun 1999 15:16:26 -0400, Ken Kelly wrote:
> >
> >> Terry,
> >> I just looked at my code. It Know it works. It will take the prom images
> >i got
> >> from the T & E chips that I removed from my PCM and convert them to a
> good
> >(%
> >> LT1 prom image? It swaps as I indicated. I sent you a copy of my software
> >to
> >> try.
> >>
> >> Ken
> >>
> >> TK wrote:
> >> >
> >> > I don't think this is right. The swap involves A0. I haven't figured
> out
> >the
> >> > others yet.
> >> >
> >> > 4FC7 winds up at 0FF6, so 1 is being subtracted in the address.
> >> > Same for 4FC8 -> 0FF7
> >> > Terry
> >> > -----Original Message-----
> >> > From: Ken Kelly <kenkelly at lucent.com>
> >> > To: gmecm at efi332.eng.ohio-state.edu <gmecm at efi332.eng.ohio-state.edu>
> >> > Date: Sunday, June 27, 1999 4:22 AM
> >> > Subject: Re: Flash swapped address line.
> >> >
> >> > >Terry,
> >> > > I built a function into my editor to swap them back and forth. It can
> >read
> >> > the
> >> > >raw Eprom format or the standard format.
> >> > >
> >> > >I think I ended up swapping A1 and A13,  A2 and A12,  A3 and A11.
> >> > >
> >> > > Ken
> >> > >
> >> > >TK wrote:
> >> > >>
> >> > >> I've been working on a 95 LT1 ECM and it's clear the address lines
> to
> >the
> >> > >> flash eproms are swapped.
> >> > >>
> >> > >> Any chance you know which ones? The first 2K should be FF and there
> >are
> >> > >> groups of non-FF bytes in there.
> >> > >>
> >> > >> Any information appreciated.
> >> > >>
> >> > >> Terry Kelley
> >> > >
> >
> >
> >
> >
> >
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> >