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Re: microcontroller ROM copy trouble ?




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Have you put the full hex dump up somewhere for us to look at?

Geo

Re: microcontroller ROM copy trouble ?



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Honestly, I just skimmed the replies, and don't have the time to get
into great detail about what might be wrong....

However, if I recall correctly, parallel EPROMs used to have
"Signature Bytes".
In the old days, that's how a programmer "knew" what programming
voltage / algorithm to use....

Could be the 8031 code is reading this, before allowing normal
operation.  (Wild ass guess, btw)
Or, perhaps more likely, your programmer isn't really programming the
new EPROM and its just lying to you.??

Hope you figure it out.  Good luck.
-mpm


Re: microcontroller ROM copy trouble ?




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Honestly, I just skimmed the replies, and don't have the time to get
into great detail about what might be wrong....

However, if I recall correctly, parallel EPROMs used to have
"Signature Bytes".
In the old days, that's how a programmer "knew" what programming
voltage / algorithm to use....

Could be the 8031 code is reading this, before allowing normal
operation.  (Wild ass guess, btw)
Or, perhaps more likely, your programmer isn't really programming the
new EPROM and its just lying to you.??

Hope you figure it out.  Good luck.
-mpm

Utter rubbish.....the 8031 isn't reading sig bytes...
Your programmer is not reading the eprom correctly.



Re: microcontroller ROM copy trouble ?


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I agree, now that I have read the replies more thoroughly, esp, post
#3, it would appear that your programmer is not reading the original
masked ROM part correctly.


Re: microcontroller ROM copy trouble ?



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I agree, now that I have read the replies more thoroughly, esp, post
#3, it would appear that your programmer is not reading the original
masked ROM part correctly.

This is what I have found out about UPD23C256E.....
The OE signal is mask option selectable and can be active hi, low or don't
care.

Put the  chip in your reader, but bend out the OE leg ( pin 22). Connect it
via a 1K resistor to Vcc and then read as 'any' 27256 EPROM.
Look at the data and see if it looks 'real'.
If not, leave pin 22 'not connected 'and read again......
I don't think it's worth trying to connect OE to GND as that is the default
for all generic 27356 devices.



Re: microcontroller ROM copy trouble ?




TT_Man wrote:

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Not to mention that if  /OE is tied in some unusual way on his board, it also
won't work with standard Eproms.

It might be an idea to see if pin22 of the ROM socker is tied low.

Graham



Re: microcontroller ROM copy trouble ?



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esp, post
original
low or don't
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22). Connect it
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is the default
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board, it also
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low.
Thanks for the help,

I tried out the ideas you suggested.

that is .... select different ROM types and i also tried with
differing read lengths for 0xf to 0x7fff or whatever the max size
is and all the same results

except that different 27cXXX types gives me different sequence of
repeated bytes

 i tried the OE pin out and jumpering pins and such

i think maybe my programmer is just crap it is an "Easypro90" and
it supports lots of chips but apparently not the one i need

i highlighted the pinout and traces of the ROM chip in another
post i will put it here ....

My pin trace  is.....
Where Rom is the same ROM there is only 1 ROM
this views best in fixed width eg. courier

Rom(pin)     Rom(pin)      8051 (pin)
------------------------------------------
A0 (p10)     D0 (p11)      P0.0 (p39)
A1 (p9)      D1 (p12)      P0.1 (p38)
A2 (p8)      D2 (p13)      P0.2 (p37)
......
A8 (p25)     ---           P2.0 (p21)
A9 (p24)     ---           P2.1 (p22)
.....
A14 (p27)    A15 (p1)      P2.6 (p27)
.....
OE (p22)     ---           PSEN (p29)
CE (p20)     ---           ALE  (p30)


one thing i have come across that may help is that the oly mask
ROM datasheet i have found (Toshiba TMM23256P) says that the chip
has Adress latch on falling edge of (CE) and the timing diagrm
shows the falling CE edge occurs in middle of address valid
section, on most 27cXXX chips the timing diagram shows the
falling edge of CE occurs just at or before the valid address
section but i do not know if that should make a diference ??

 Thanks for all the help Graham, as i relly need it to get out of
this jam.

do you think it would be difficult to program a 8051 development
board to read this data and say dump it somewhere to pick it up .

seems like it should be easy enough ???  i have a PJRC Rev 4
board  http://www.pjrc.com /
that i got with the ROM programmer pretty cheap

i do not know if my Programmer will alloew you to write a custom
algorithm but i ahve not found any info on the easypro site to
that regard.

thanks again,
robb


Re: microcontroller ROM copy trouble ?



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post
original
low or don't
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22). Connect it
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the default
thanks TT_MAN,

ok, interesting experiment,

when i tie the p22 (oe) high then i read all 0xFF all the way
floating gives similar  as  when connected


reading a troshiba 23256 mask rom datasheet it showed that the
latch occurs at trailing edge of (CE) so (CE) falls about halfway
through the adress valid ... but most timing diagrams for 27cXXX
chips show the (CE) falling  at or  just before the address valid
section

so i do not know how that timing could affect what i am doing. i
suppose i need to find out what the ROM programmer is doing.

programmer is an "Easypro90" if anyone has any knowledge of
these?

thanks for helping,
robb


Re: microcontroller ROM copy trouble ?




robb wrote:

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Now tie it low.

AND look at how it's connected on the equipment pcb.

Graham


Re: microcontroller ROM copy trouble ?



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Exactly.

Robb,

I don't think the Easy Pro 90 can read the D23256ac because the chip
is too slow, (150 to 250ns).

Here what I would do. Build a simple adapter to your printer port and
strobe the address lines to read the data bits off the D23256ac.
Remember the slower the read the better for you.
Also the speed of you computer will affect your reading. If you can
connect an oscilloscope to you printer port (even the Easypro 90 to
pin A1 ), you can figure how fast it is reading the D23256ac.

Once you got the image file you can burn the ST M27C256B (45ns) with
your Easypro 90.

In case you want to update the Easypro 90 software, you can grab it
from http://www.programtec.com/english/main.asp .

Don't bother contacting tech support because they never reply.


Ping Robb Re: microcontroller ROM copy trouble ?




robb wrote:

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Do you have a plain 'vanilla' example of an 8051 application circuit
with external ROM showing the connection of the address and data lines
(and address latch) ?

In view of comments made, I suggest that you 'buzz out' all the address
and data line connections between the 8051 and the ROM on your board and
report back to establish if there's anything unusual here.


Graham


Re: Ping Robb Re: microcontroller ROM copy trouble ?


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circuit
data lines
address
board and

Appologies for late turn around reply,
finishing up X-mas mode, returned from 4 hour drive to relatives
this PM.

Just wanted to give a quick reply before sleep.... so that you
didn't think i gave up on your much appreciated help.

The ROM/MCU does connect to other chips but does not go through
them. That is, my original pinout diagram of the ROM lines to MC
line relations holds true, there are direct traces from the ROM
Addr/Data lines to MCU's ports 0 and 2.

but also the  ROM Addr 0-7 is connected to the inputs  1D,2D
etc.... of   3 diff SN74LS377 (D-Type Flip-Flops)  the output of
the Flip-FLops 1Q,2Q ...   connect to either a Static Ram chip's
(SRM2016) Address lines and the SRM data lines are also connected
to the I/O port 1 of MCU

the LS377 has connections to other chips around the MCU eg.
(74LS251, 74LS28B, 4049, others)

I will work on a more complete pin connections, i origianlly just
posted to show that the ROM pins were consistent with 27cXXX
series chips.

My chepao chim=nese reader did supoprt the chip that someone
suggested the D87c257 and i get something alot more promissing
shown below...

i do not know if it is good yet as i do not have any more blank
ROM chips to burn  and i have not tried to load into a 8051
dis-asembler

thanks for all the help Graham,
robb

D87c257 read....
----------------------
:020000040000FA
:1000000002096FC0D0C0E0020173FFC0D0C0E0029F
:1000100001BEFF30B202D22A32FFFFC0D0C0E0C022
:1000200082C083C000904058E531540F204C073007
:1000300045036001040423F893F58DE80493F58BE0
:10004000E542540790405093F8E541540793C44863
:10005000758360F0206F26D294E530758350F0E50B
:100060002D543F7041C245C28E206F19205D1E1273
:100070000F39D000D083D082D0E0D0D032204DD9FB
:100080007530FF80D4205C4C12154A80E5E5422093
:10009000E002C294E530758350F080D6E54120E05F
:1000A000F353307780EE14601314147002D24CE5D1
:1000B0003130450C540F600215313164316480B227
:1000C000C4B53109C24C1046F1D24580ED104CEA5E
:1000D000053180E6104DC5E520440F20E701C4F549
:1000E00030758DFBD28ED24D53200F80854320F08A
:1000F000E52D543F603AFDF5317842306F0118E646
:1001000030E0021531E531C313B4020575310A80C0
:100110000DC394035001E4C3139246C4F531E6D2F3
:100120004C20E009C24CED1460031201641201641A
:10013000208E20306F06E530C4B53009758DFF750F
...........
...........
:10096000D23D22D23C22E0540F24F650F3808D7504
:1009700090CC797E7802760008D9FB75B8E175894C
:1009800011758CFE75880575A8867583607444F0B2
:1009900075835074FFF530F0758D88D28ED2137543
:1009A000530AD28C120D60308FFA7583507477F52C
:1009B00030F07455758360F0C28F758D88120D60AC
:1009C000308FFA906007E030E002D20A756DE0D215
:1009D00014D2131230A8754400C22C121808C28E0B
:1009E000C28FD2AB1229FCD2192019F82018F5A217
:1009F000B492E0A2B592E1F45403F52B3014102028
:100A0000200D204A472010031218EAC214C2131204
:100A100029FC304A082011E4200DE1800DE5445402
:100A2000F0B4F006202FD52010D220182AD293D26D
:100A300092C295C2D3C2D4A2B492E0A2B592E1F41C
:100A40005403FAE52B5403B5023980B02011BC20C1
:100A50000DB91231A780B4D2193014057553008036
:100A60009B3018C93092298043501E120CAEEA60A8
:100A700030B4030A205A12D25A1213157403120DFD
:100A8000428006EA20E0E250E2532BFC422B21FC9C
:100A9000C293D295C291E543B4569CC290D2A8802D
:100AA00096305AE5C25A120EA5E480DD7552A0C2F6
:100AB00093D292C20A304102D291E543B45602D297
:100AC00090752E00750600D215754D00120CAEC241
:100AD00089D2A8301E04C22AC21EC25A205646E538



Re: microcontroller ROM copy trouble ?


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Where are you located in the UK?



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