Intel 2704 questions

[Riviera]

Wondering about the Intel 2704 as it is a 4096-bit (512x8) EPROM and has the same core as the 2708 8192-bit (1024x8) could it be that Intel used chips that had non working bits on one half of the chip but the other half working?
Or did they just left out one connection pin making only 4096 bits addressable?
looking at the die I cant see any connections missing.





/Rivie

[kosmokrator]

well i think its hard to tell isdiference by Optical inspection.....maybe the Top Layer Looking The Same But Some Inner Pad-Metal-Silicon Layer Missing.....So Voilla..... Diferent Specs On the Same maSk Chip .....
Just my thougts....Not Sure About

[Tegranphos]

or some burn fuses in ensambling proccess

[chip68]

http://www.cpushack.com/2010/06/08/unlocking-eprom-cores/

- CMW

[Neon_WA]

[Elar]

Datasheet for 2704 says that pin22 (A9) must be tied to GND. So, there's no modifications for internal connections/die. The 2704 is just the 2708 with broken upper half.

[attilavv]

Hi,

where i can found datasheet for INTEL 2704 ?
I have not found on the web.

[Neon_WA]

[attilavv]

Neon_WA,

Thanks for Datasheet.

It not for "collector".
I have a pair old old French computer, the First French computer and the board use 2704 / 2708.

And i have a 3 2708 from Intel ( i am looking for 1 ou 2 2704 ) but all datasheet on the web is not complete. It is no information for Tpw ( Time Pulse for programming ).

Thanks again.

[Neon_WA]

I just checked the datasheet for Tpw
lists it as Min 0.1ms Max 1.0ms

let me know if you require the Signetic datasheet

If you have 2708s.. why do need the 2704s? (you can program the 2708s as 2704s)

What do you have to program the eproms?

[attilavv]

For other datasheet, it is OK.
TMS2708 and some other. Easy on the web.

2704 only for the fun !
At this time, this computer have the CPU card and a FPU card and the "bios" ( boot PROM is in this card and are 2716 ( compatible 2732 ).

I have 50 floppy ( not read at this time but not compatible ) and probably some old system boot PROM. Probably some for 2704 / 2708.

Next, it for make a boot PROM on a 2704, only 512 bytes !


If you have other datasheet for 2704 compatible.
Many have a VPP of -50 / -40 ! ! !



For programming the 2708 ( VPP 26V, not -50/-40 ) i have a burner on this old computer.


You can see my old Alcyane on this site :
http://www.win3x.org/

The burner card is not present.
At this time, she is modified for 2732 only !
Some track are cut, some TTL are missing.
I have finish the schematic and found logic missing TTL.
Priority is TURN ON with floppy working.

Alcyane is a system multi user and multi CPU ! ! !
You can see the big documentation of Alcyane here :
http://attilavv.free.fr/alcyane/Documentation/Alcyane.pdf

Scanned by my ...
I have some contact with man that have worked in MBC ( originaly MBI computing in reserve sense ... and the "good" sense have need to change it ).
This computer have been make when France decide to make Nuclear program and USA have added France in black list, Devil Axe ...

[Neon_WA]

I just sent you datasheets for

Signetics 2704/2708 (seems identical to Intel)
National Semi 4204/5204

[attilavv]

For Nationnal : Vdlp = -50V max / -48V min
Very are for programming but high and negative !

Intersil 6654 ... VPP = -40V ... hard for programming too.

For the Signetics, it is same classique 2708 but copy of Intel probably ( licence Intel ? )

It is too the AM2708 ( AMD ) i have 7 AMD and 3 Intel, all "new" model ( not white / gold ). The AM2708 is same the Intel for programming.

[Neon_WA]

[attilavv]

Hi,

Yes hard to find and hard to programming.

At this time, my first projet is the Alcyane ...
After i have the projet to build a USB Programmer for many, many, many EPROM. Only EPROM not uController but differe.

Problem for many old PROM is no compatible pin.
2708 / 2704 ( standard but Intel ... ) use same pin.
Data but is in the bottom and some have data pin in one row ( 1/12 but no on 13/24 ).

For programming a 2708 it is not easy ... N cycle of all bytes. For this, it is only software.

Other problem is -5 +5 for logic card ( or 3.3V ) -12V and VPP ... 26V ( 25/27 ). with USB port ... 5V ! ! !
Now, if some PROM have -40V / -50V and other ... it is hard !

For other PROM, it need many transistor ... big card !
For standard PROM, it only 4 Pin for special VPP /VCC.