GQ-4X and 2708's

wrongdon

New member
Joined
Jan 1, 2010
Messages
481
Reaction score
1
Location
wellington, Ohio
I have the GQ-4x programmer and it does not support 2708's.I have a head on bordset and a space firebird boardset.These are loaded with 2708's and i am about out of 2716's.Not to mention that i'm cheap so i'd like to use these 2708's .
The mcumall website says you can easily add devices by simply editing a text file.I just figured i would get the conversation started and see if someone has already written this text file or one for a different device that can throw some advice my way.My 3 month old is practicing baby talk and i don't dare try and do some deep thinking when he is awake.
But i will dig into it soon.
 
I wish I had the answer for you, but that's really cool if you can add devices to the programmer like that. I bought mine a few months ago and it's worked great so far. It helped me finish reviving my Punisher PCB.
 
Well this doesn't look to tough.Here are the directions for modifying the text file.

Syntax: Name="Device Name",ID="Device ID in Hexadecimal",Class="Class Name",Category="Category Type",MFG="MFG Name",Speed="Default Speed",Package="Package",Adapter="Adapter",CodeSize="Code Size",EepromSize="Eeprom Size",DIP="DIP Setting",VCC="Vcc",WVPP="Write Vpp",WVCC="Write Vcc",BVCC="Blank Vcc",RVPP="Read Vpp",Message="Message to User";
; Note:
;

And here is the line from the text document for a generic 12v program voltage 2716.
Name="27C16B(12.7V Vpp)",ID="XXXX",Class="27C16(12.7V Vpp)",Category="EPROM",MFG="ALL(Generic)",RVpp="5V";

So i changed this up for the 2708 as i have the AM2708 with 12v programming voltage,but the program didn't like it because the class "2708" doesn't exist.So i need to see first how to add the class for 2708 and then i think i can add individual variations of the 2708.
 
Never mind,if i am reading the datasheet correctly the AM2708 requires +12,+5 and -5v to program.And i don't believe the GQ-4X supports 3 voltage eproms.Oh well,it kept me out of trouble for a few hours and i learned some stuff.Correct me if i am wrong though,i would love to use these up and save the larger eproms for other projects.
 
You aren't wrong...

Most current programmers won't do a 2708... and most older programs won't do the oddball 2704 or TMS2716 which are both tri-voltage EPROMs.

RJ
 
This reminds me that I picked up this giant beast of a prom programmer, and totally forgot about it! Looks like a cash register and even has a tiny little screen on it.
 
These boards will be a learning experience for me as i don't fully have a grasp on strapping yet.The voltages are easy enough and i got that,but the rest of it hasn't sank in yet.Wait for the post titled either HEAD ON or SPACE FIREBIRD and 2716's haha.
 
Those are outta my league but speaking from my limited experience, your SI experience should help it makes sense...

Part of the strapping has to deal with voltages and the pinouts of the chip itself...you have xyz signal and it has to go to the proper leg. Thats the S2/S3 part of the SI strapping.

Then you have to understand that the board enables the rom as it reads it (at least SI does), and does this using the address lines. If the board knows there's only an 8k rom in each socket, its not going to keep that same chip enabled to read something past 8k, its going to enable the next chip/socket. That was the S6 part of the SI deal, and why you can just put 2716s in 3 sockets instead of 6 2708s. The has to know where to find the rom data.

Clear as mud?
 
Those are outta my league but speaking from my limited experience, your SI experience should help it makes sense...

Part of the strapping has to deal with voltages and the pinouts of the chip itself...you have xyz signal and it has to go to the proper leg. Thats the S2/S3 part of the SI strapping.

Then you have to understand that the board enables the rom as it reads it (at least SI does), and does this using the address lines. If the board knows there's only an 8k rom in each socket, its not going to keep that same chip enabled to read something past 8k, its going to enable the next chip/socket. That was the S6 part of the SI deal, and why you can just put 2716s in 3 sockets instead of 6 2708s. The has to know where to find the rom data.

Clear as mud?[/QUOTE

The S6 portion of the clowns boards made sense to me to the extent that changing these jumpers will let it know to continue reading the same eprom longer.But i don't understand the "how" of it all.
As far as getting the right voltage to the right pin,that's pretty easy and the address lines i can figure out using the datasheets of the old and new eprom.At least i have it figured out enough not to smoke anything.Head on will be fun as i see no pads or jumpers for strapping,so i may have to get creative.May try a single rom mod on it,it originally had 7-2708's.
 
Back
Top Bottom