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 using AT29C256 in place of 2732?
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RRice

1 Posts

Posted - 08/15/2006 :  01:30:28  Show Profile  Reply with Quote
Not sure if anyone here can help me or not,, and if i'm posting my question on the wrong forum my opologies,, i want to use an AT29C256 in place of an older 27C32 eprom,, the problem is i dont know where each pin should go to make the adapter needed. Can anyone here post a 27C32---> AT29C256 pin to pin diagram for me?

Thanks,
Rick
Reply #1

ZLM

2937 Posts

Posted - 08/15/2006 :  11:09:44  Show Profile  Reply with Quote
The 27C32 is a 24 pin EPROM and 29C256 is a 28 pin EPROM, they are not directly replaceable.

You need a special adapter if you want to replace the 27C32 by 29C256.

The 29C256 has more address lines, you can just connect those address lines (not existed in 27C32) to GND on your adapter. Also, the WE of 29C256 need to be connected to VCC on your adapter.

2732
4kx8 EPROM. 
    +-----+--+-----+
 A7 |1    +--+   24| VCC
 A6 |2           23| A8
 A5 |3           22| A9
 A4 |4           21| A11
 A3 |5           20| /OE 
 A2 |6    2732   19| A10
 A1 |7           18| /CE
 A0 |8           17| D7
 D0 |9           16| D6
 D1 |10          15| D5
 D2 |11          14| D4
GND |12          13| D3
    +--------------+


AT29C256   32kx8 FLASH. 

    +-----+--+-----+
WE  |1    +--+   28| VCC
A12 |2           27| A14
 A7 |3           26| A13
 A6 |4           25| A8
 A5 |5           24| A9
 A4 |6           23| A11
 A3 |7  AT29C256 22| /OE
 A2 |8           21| A10
 A1 |9           20| /CE
 A0 |10          19| D7
 D0 |11          18| D6
 D1 |12          17| D5
 D2 |13          16| D4
GND |14          15| D3
    +--------------+

Edited by - ZLM on 08/15/2006 11:21:02
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