2708 EPROM PDF

The restoration of computers like our SAGA FOX LS, containing an EPROM , gave us the necessity of reading, and so storing, the. , , , , , , 27C, , 27C, , 27C, 27C, , , EPROM series. EPROM and CMOS. The Bytesaver card only uses eproms, but I’ve managed to create a socket adapter to use ‘s instead. And I’ve used the Top

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I tried reading a in the adapter and that didn’t work. Thread Tools Show Printable Version.

File:2708 EPROM installed in Cromemco Bytesaver.jpg

All this means is that your will not enter standby mode i. This should, therefore, mean that you would need to program the “low half” of the ? Anyone know why this would be?

Circuit To read a eprom we need 10 output for the address bus, and 8 input for the data bus: The front panel switches are all still good and working, but I can tell some of the most used switches like examine next and deposit are starting to get a little worn out. I have a 2k monitor program in the top 1k of two ‘s, in two sockets each with an adapter, and the program runs as 2k of continuous memory.

We’ll assume you’re ok with this, but you can opt-out if you wish. I would suspect, therefore, that pin 18 is connected to ground by default logical ‘0’ when it is read mode. I think the key is pin 21 on thethis pin doesn’t affect reading on thebut the way I have it wired would stop reading on the The time now is The other confusing thing is that you say you program the “high half” of the – but pin 19 A10 is linked to ground.

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Monday September 10th, Tuesday August 5th, admin. I checked the Cromemco Bytesaver schematics and there eprmo a pull-down resistor on this pin. Whilst you say your adapter works and I am not disputing this the datasheet states that pin 21 VPP should be connected to VCC for correct read operation.

The Bytesaver card only uses eproms, but I’ve managed to create a socket adapter to use ‘s instead. We need to wait the correct time for the data to be burned about 1 ms according to the datasheet and put back to ground the programming pin Originally Posted by kingchops.

Moreover, we need a way to transmit data to a PC, so we need other two pin for a eprkm port. Then I just program the top half of the ‘s and they act as ‘s on the card.

Dave, Thanks for the info, my current adapter is working. Perhaps there are some which ignore this pin – or it is 22708 “no connect” pin. What I also tried was to use eeproms.

I am still eprlm bit confused by your pin I should also mention that I don’t want to program the ‘s or ‘s when they are in the target system, just read is fine. I’ll make up and adapter with you fprom and try it out. Forum Genres S eprom substitution, In my reasearch I’ve read that ‘s are pin compatible with ‘s so I figured I could use the same adapter with ‘s. Facebook Twitter Google Email Print.

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File EPROM installed in Cromemco – Wikimedia Commons

So, the pin 22that in the is the 9th address line, in the is a ground. We must simply set the A1 digital port connected to pin 22 of the EPROM to zero, and read only the values between 0 and I have to agree with everything Dave says.

As I said I will try Dave’s suggested wiring and post results I expect it will work better. I’m still not getting this: At this point we have to simply write on the address bus A0…A9 the address of the location to program, in the data bus Q0…. Sorry, your blog cannot share posts by email.

Data is trasmitted to the serial port as an ASCII character, representing the hexadecimal value that has been read. The pinouts and voltages are drastically different.

All times are GMT The software suite is divided in two pieces: I’ve got an 8k Bytesaver card in my machine which I’ve loaded up with the 8k Basic bootloader. So it seems the adapter as I originally wired it only works for ‘s. I appreciate the input and don’t get me wrong I accept what you guys are saying. I am not sure what the other logic does on this pin as I only located a partial schematic.