DIP28 -> DIP23 Adapter or Circuit

[Borg Number One]

I have got many DIL28/DIP28 EEPROMS (from old mainboards) for example:

AT27C256R (Atmel)
NM27C5120-150 (NATIONAL Semiconductors)
TMS27C512-15 (Texas Instruments)
AM27C512-155DC 150B821 (AMD)

and I would like to use them.

Exist adapters / "converter circuits" which make it possible to use them with a DIL32 socket?

If not, would it be possible to build such "converter circuits"?

[sulbert]

At least first one is OTP EPROM according to the datasheet. Adapter building instructions can be found here (in German).

[Tomasz]

Sulbert: any link in english, please..?
Tomasz.

[Borg Number One]

Code: Select all

DIL/DIP28       DIL/DIP32

                1  O   O  17
                   O   O
1  O   O  15       O   O
   O   O           O   O
   O   O           O   O
   O   O           O   O
   O   O           O   O
   O   O           O   O
   O   O           O   O
   O   O           O   O
   O   O           O   O
   O   O           O   O
   O   O           O   O
   O   O           O   O
   O   O           O   O
14 O   O  28	 16 O   O  32

Referring to this:
http://www.geocities.com/SiliconValley/ ... re.html#6i

How is it possible to put pin 14 + 15 of the 28-pin sockel to pin 16 +17 of the 32pin sockel?????????
(Only this would possible/realizable:
Either putting pin 14 to pin16 or pin 15 to pin 17.)

Is it possible to stretch DIPs now????

Or do you mean this?

Code: Select all

DIL/DIP28       DIL/DIP32

                0  O   O  16
                   O   O  17
0  O   O  14       O   O
   O   O  15       O   O
   O   O           O   O
   O   O           O   O
   O   O           O   O
   O   O           O   O
   O   O           O   O
   O   O           O   O
   O   O           O   O
   O   O           O   O
   O   O           O   O
   O   O           O   O
   O   O           O   O
13 O   O  27	 15 O   O  31

[Rainbow]

DIPs are always numbered like this:

Code: Select all

1  O   O  28
   O   O
   O   O
   O   O
   O   O
   O   O
   O   O
   O   O
   O   O
   O   O
   O   O
   O   O
   O   O
14 O   O  15

General rule for inserting smaller DIPs is this:

Code: Select all

DIL/DIP28       DIL/DIP32

                1  O   O  32
                   O   O
1  O   O  28       O   O
   O   O           O   O
   O   O           O   O
   O   O           O   O
   O   O           O   O
   O   O           O   O
   O   O           O   O
   O   O           O   O
   O   O           O   O
   O   O           O   O
   O   O           O   O
   O   O           O   O
   O   O           O   O
14 O   O  15	 16 O   O  17

This applies also to DIP cache chips on older boards.
However, you might have to connect the VCC pin of the chip to 5V instead of the socket.

[Borg Number One]

In conclusion this would be the solution to build a 28-to-32-pin-socket-adapter to read the content of the 28pin (E)EPROM/FLASHROM.

Code: Select all

DIL/DIP28      DIL/DIP32      DIP28 (socket)=>DIP32 socket

                       (VCC)
               1  O   O  32
                  O   O
 1 O   O 28       O   O           1=> 3   28=>32(!)   28 should not be connected to 30
 2 O   O 27       O   O           2=> 4   27=>29
 3 O   O 26       O   O           3=> 5   26=>28
 4 O   O 25       O   O           4=> 6   25=>27
 5 O   O 24       O   O           5=> 7   24=>26
 6 O   O 23       O   O           6=> 8   23=>25
 7 O   O 22       O   O           7=> 9   22=>24
 8 O   O 21       O   O           8=>10   21=>23
 9 O   O 20       O   O           9=>11   20=>22
10 O   O 19       O   O          10=>12   19=>21
11 O   O 18       O   O          11=>13   18=>20
12 O   O 17       O   O          12=>14   17=>19
13 O   O 16       O   O          13=>15   16=>18
14 O   O 15    16 O   O  17      14=>16   15=>17

Can this adapter be used to write data too?

[Tomasz]

Look out to merge chip 28DIP with chip 32DIP!
According to, for example, Atmel's chip:
AT28C64B (28DIP) --> AT29C010A (32DIP, comon flash memory for BIOS'es upgrades) - comparing pins as described in Atmel's datasheets:

28DIP 32DIP
........................................ NC-1 | | 32-VCC (5V)
........................................ A16-2 | | 31-WE
NC-1 | | 28-VCC......... A15-3 | | 30-NC
A16-2 | | 27-WE............ A12-4 | | 29-A14 - leave not conn.
A15-3 | | 26-NC............ A7 -5 | | 28-A13 - leave not conn.
A12-4 | | 25-A8............. A6 -6 | | 27-A8
* | | * ........................... * | | *
GD-14 | | 14-I/O3...........GN-16| | 17-I/O3

and in 32DIP (2)&(3) - leave not connected..!

Now I try to connect socket 28pins with socket 32pinsP and flash
smaller chip via such "adapter" with UNIFLASH... I need much luck, I suposse!
Tomasz.

[Borg Number One]

-delete this-

[Tomasz]

Borg - it is what I mean!
Tomasz.

[Borg Number One]

-delete this-

[Tomasz]

YES! But they should be:
DIP28: 28=>32 DIP32
DIP28: 27=>31 DIP32
DIP28: 26=>30 DIP32
DIP28: 25=>27 DIP32
DIP28: 24=>26 DIP32
etc...
So, VCC to VCC in DIP28 & DIP32! (28=>32)
DIP32: 28.&29 - not connected.
Next time I give foto of my "adapter", OK?

Tomasz, POLAND.

[Tomasz]

Well, I've tried to hot-swap flash AT28C65B with Uniflash. I hot-swapped in mobo "5v-1A" BIOS socket but it seems uniflash does not support chip AT28C64B... But if that chip will be implemented into Uniflash..?
I used combination of two "precision" sockets 32DIP --> 28DIP, and prepared their pins for socket 32DIP. Details: next letter with Photos.. B-)
Tomasz, POLAND.

[Borg Number One]

Yeah...photos please...
Photos in this way:

Code: Select all

DIP28
--------------
--------------
||||||||||||||
||||||||||||||||
----------------
Sockel: DIP32

[Rainbow]

Well, I've tried to hot-swap flash AT28C65B with Uniflash. I hot-swapped in mobo "5v-1A" BIOS socket but it seems uniflash does not support chip AT28C64B... But if that chip will be implemented into Uniflash..?

This is an EEPROM so there is no identify command -> no autodetection. However, it might be possible to implement EEPROM support by (ab)using the -force parameter...sometimes.

[Borg Number One]

@Tomasz:

Code: Select all

DIL/DIP28      DIL/DIP32      DIP28 ((E)/EPROM/Flashrom/socket)=>DIP32 socket

                       (VCC)
               1  O   O  32           1      |===>32
                  O   O               2      ||==>31
 1 O   O 28       O   O           1   3   28=|||=>30
 2 O   O 27       O   O           2=> 4   27==||  29
 3 O   O 26       O   O           3=> 5   26===|  28
 4 O   O 25       O   O           4=> 6   25=====>27
 5 O   O 24       O   O           5=> 7   24=====>26
 6 O   O 23       O   O           6=> 8   23=====>25
 7 O   O 22       O   O           7=> 9   22=====>24
 8 O   O 21       O   O           8=>10   21=====>23
 9 O   O 20       O   O           9=>11   20=====>22
10 O   O 19       O   O          10=>12   19=====>21
11 O   O 18       O   O          11=>13   18=====>20
12 O   O 17       O   O          12=>14   17=====>19
13 O   O 16       O   O          13=>15   16=====>18
14 O   O 15    16 O   O  17      14=>16   15=====>17

@DIP32
2, 3, 28, 29 are not connected.

Is this correct now?
Well, I have built a small unit/component which makes it easier to change EEPROMS.
You can see a testsocket with a lever to de/attach EEPROMS.
On the testsocket I soldered a normal DIL 32 Socket, because the pins of the testsocket are to wide. So it would not suit into the Mainboard-Sockel.
However the soldere sockel makes it possible.



@Rainbow

...please insert a switch which makes it possible to write/read data to/from the (E)EPROM/PROM-Sockel even if no chip was detected.

So it would be possible to read/write (E)/E/PROMS which have no identification.

In conclusion this would be the solution to the mentioned problem.