I had ERASEd the device first, but I can try again.
First I dump a few bytes:
Code: Select all
>DUMP 28F256
00000,50
00000 C3 00 00 13 10 07 FF FF C.....
00008 C3 7B 11 AE 0C BC 0C FF C{...<.
00010 FF FF FF FF FF FF FF FF
00018 FF FF FF FF FF FF FF FF
00020 FF FF FF FF FF FF FF FF
00028 FF FF FF FF FF FF FF FF
00030 FF FF FF FF FF FF FF FF
00038 FF FF FF FF FF FF FF FF
00040 FF FF FF FF FF FF FF FF
00048 FF FF FF FF FF FF FF FF
>DUMP 28F256
00050,50
00050 FF FF FF FF FF FF FF FF
00058 FF FF FF FF FF FF FF FF
00060 FF FF FF FF FF FF FF FF
00068 FF FF FF FF FF FF FF FF
00070 FF FF FF FF FF FF FF FF
00078 FF FF FF FF FF FF FF FF
00080 FF FF FF FF FF FF FF FF
00088 FF FF FF FF FF FF FF FF
00090 FF FF FF FF FF FF FF FF
00098 FF FF FF FF FF FF FF FF
Not completely blank. Erase it (again):
Code: Select all
>ERASE
AMD 28F256
12.00V Burn pin 1
Writing All Zeros
Erasing
Done.
Dump again, just to be on the safe side:
Code: Select all
>DUMP 00000,50
00000 C3 E2 00 13 10 07 FF FF Cb....
00008 C3 7B 11 AE 0C BC 0C FF C{...<.
00010 C3 1C 03 FF FF FF FF FF C..
00018 C3 DA 02 FF FF FF FF FF CZ.
00020 C3 47 2B FF FF FF FF FF CG+
00028 FF FF FF FF FF FF FF FF
00030 FF FF FF FF FF FF FF FF
00038 C3 EE 33 52 4F 4D 20 76 Cn3ROM v
00040 35 2E 34 20 44 61 74 65 5.4 Date
00048 64 3A 20 30 38 20 4F 63 d: 08 Oc
>DUMP 00050,50
00050 74 20 32 30 31 33 00 44 t 2013.D
00058 2D 58 20 44 65 73 69 67 -X Desig
00060 6E 73 20 50 74 79 20 4C ns Pty L
00068 74 64 2C 20 50 65 72 74 td, Pert
00070 68 20 41 75 73 74 72 61 h Austra
00078 6C 69 61 00 ED 57 67 ED lia.mWgm
00080 38 33 C6 04 6F 7C B5 C9 83F.o|5I
00088 F3 21 01 00 ED 21 0F ED s!..m!.m
00090 29 0E ED 21 0D ED 29 0C ).m!.m).
00098 ED 38 10 F6 11 ED 39 10 m8.v.m9.
That doesn't look right to me. Now, what does the TEST command give?
Code: Select all
>PRETEST 28F256
00000-07FFF=00000
BLANK ROM
It claims it is blank? Hmm, let's see if the dump command agrees:
Code: Select all
>DUMP 00000,50
00000 C3 E2 00 13 10 07 FF FF Cb....
00008 C3 7B 11 AE 0C BC 0C FF C{...<.
00010 C3 1C 03 FF FF FF FF FF C..
00018 C3 DA 02 FF FF FF FF FF CZ.
00020 C3 47 2B FF FF FF FF FF CG+
00028 FF FF FF FF FF FF FF FF
00030 FF FF FF FF FF FF FF FF
00038 C3 EE 33 52 4F 4D 20 76 Cn3ROM v
00040 35 2E 34 20 44 61 74 65 5.4 Date
00048 64 3A 20 30 38 20 4F 63 d: 08 Oc
>DUMP 00050,50
00050 74 20 32 30 31 33 00 44 t 2013.D
00058 2D 58 20 44 65 73 69 67 -X Desig
00060 6E 73 20 50 74 79 20 4C ns Pty L
00068 74 64 2C 20 50 65 72 74 td, Pert
00070 68 20 41 75 73 74 72 61 h Austra
00078 6C 69 61 00 ED 57 67 ED lia.mWgm
00080 38 33 C6 04 6F 7C B5 C9 83F.o|5I
00088 F3 21 01 00 ED 21 0F ED s!..m!.m
00090 29 0E ED 21 0D ED 29 0C ).m!.m).
00098 ED 38 10 F6 11 ED 39 10 m8.v.m9.
I haven't got a clue what is going on here.
Is there a difference between the Am28256 (which the S4 supports) and the Am28F256A (the chip I have).
Unfortunately, I have only this chip, so I can't try another one.