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Mostek MK37013P datasheet?

tingo

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Does anyone have a datasheet for a chip called Mostek MK 37013P?
See the top chip (U31) in the attached picture.

This chip is supposedly a PROM. On the schematics it is listed as "2716 / 2764 / MK37013", and the only configuration jumper (on the schematic) is to tie A11 to +5V if it is not in use.
This is from a Tandberg TDV 2200/9 terminal, which has a 8085 processor. The Hardware manual, which contains the schematics can be found here: http://heim.bitraf.no/tingo/nd/non-nd-documents.html
(mainboard, page 1 of 4).
 

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The reason that you can't find a datasheet for the specific part is because Mostek used general numbers (e.g. MK36000 for the 64Kbit 24 pin, MK37000 for the 64Kbit 28 pin, MK38000 for the 256Kbit...) for the series of factory-mask-programmed PROMs. Thus, the MK37013 identifies a mask ROM made for Tandberg.

So, see PDF page 41 here for the MK37000.
 
That explains why I couldn't find it - thanks!
Unfortunately, after checking the datasheet against a 2764 datasheet, I can't understand why I can't read the contents of this PROM with my EPROM programmer (tried both a MiniPro TL866 C/S and a Dataman S4). I can override the wrong signature on the MiniPro, and it reads it as a 2764, but all bytes are FF - clearly not correct. Any idea on how to read the contents of this chip with an EPROM programmer?
 
You might need to do something with the OE or CE pins. I had to do that to read the mask roms for my compaq portable and deskpro. I think on those chips I jumped OE to vcc when in the programmer. But you probably want to check what the is actually happening in the socket in the system.
 
The MK37000 is a clocked chip; a cycle commences on the falling edge of CE/ where the address is assumed to be stable and data is presented on the rising edge of CE/.

This is a bit different from a bog-standard 2764, which is a static chip. It's quite likely that your programmer just pulls CE/ low for as long as it needs to access the chip.

But that's just my guess from reading the datasheets.
 
I've used my GQ4 to read a Mostek 37xxx before, Try reading it as a ATMEL AT28HC64,

Tried that
Code:
tingo@kg-core2$ ./minipro -p AT28HC64 -r ~/doc/Tandberg/TDV2200/EPROMs/TDV2200_U31_Mostek_MK37013P.bin
Found TL866CS 03.2.86 (0x256)
Reading Code...  0.14Sec  OK

tingo@kg-core2$ ./minipro -p AT28HC64B -r ~/doc/Tandberg/TDV2200/EPROMs/TDV2200_U31_Mostek_MK37013P_2-2.bin
Found TL866CS 03.2.86 (0x256)
Reading Code...  0.15Sec  OK

tingo@kg-core2$ ./minipro -p AT28HC64BF -r ~/doc/Tandberg/TDV2200/EPROMs/TDV2200_U31_Mostek_MK37013P_2-3.bin
Found TL866CS 03.2.86 (0x256)
Reading Code...  0.15Sec  OK

tingo@kg-core2$ ./minipro -p AT28HC64L -r ~/doc/Tandberg/TDV2200/EPROMs/TDV2200_U31_Mostek_MK37013P_2-4.bin
Found TL866CS 03.2.86 (0x256)
Reading Code...  0.15Sec  OK
Unfortunately, the result is the same:
Code:
tingo@kg-core2$ hd TDV2200_U31_Mostek_MK37013P_2-4.bin
00000000  ff ff ff ff ff ff ff ff  ff ff ff ff ff ff ff ff  |................|
*
00002000
either my EPROM programmers aren't up to the task, or the chip is broken somehow (I get inconsistent results trying to dump it with the Dataman S4). Or the chip requires clocking, as Chuck(G) says.
 
FYI, just in case it helps someone, the dumps from EPROMs I was able to read are available from the ND246 page on NDwiki. ND246 is ND's product number for the Tandberg TDV 2200/9 terminal. They might be useless without the contents of the Mostek MK37013P ROM, but who knows.
 
Does your programmer support the MK2764? This slightly older databook, page 62, suggests the MK37000 and it were pin compatible. It doesn't mention the clocked access though, unfortunately, so I have no idea if it would work, but perhaps it's worth a try. I've got a couple of programmers that say they support MK2764.
 
Doesn't look like the minipro supports it:
Code:
tingo@kg-core2$ ./minipro -L 2764
No TL866 device found. Which database do you want to display?
1) TL866A
2) TL866II+
3) Abort
1
AM2764A@DIP28
AM2764A@PLCC32
CAT2764A@DIP28
CAT2764A@PLCC32
MBM2764@DIP28
MBM2764@PLCC32
GR2764@DIP28
2764A@DIP28
2764A@PLCC32
UPD2764@DIP28
M2764A@DIP28
ST2764A@DIP28
M2764A@DIP28
ST2764A@DIP28
TMS2764@DIP28
 
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