RC2014 EEPROM's and using USB TL866CS Universal EPROM writer

[Derrick Green]

All,

It has been a week or so now since I have my RC2014 up and running. I even put together a banked 64KB SRAM and EEPROM board that I ordered from osh park from through smbaker's site. Everything appears to have tested correctly after I set the default jumpers to A14 and A15 to the upper positions using 00. I am looking to dig a little deeper in learning how to copy binary Assembly and other sources on a blank EEPROM. I have the same exact EEPROM that came with the kit and a few others. I was wondering if the 16K M27128 would also work? As far as I could tell the pin configuration is nearly the same. I also ordered the EEPROM programmer and appears to work with 27512 and 27128 chips. I wanted to first start by practice writing EEPROMs before I dug in further putting the CP/M projects I see on his sites and understand more on how the Z80 works. I will also update this post when I get the EEPROM writer. Suggestions? 

Link's:

http://www.smbaker.com/z80-retrocomputing-11-cpm-on-the-rc2014

http://www.autoelectric.cn/en/TL866_main.html

[Spencer Owen]

Hi Derek,

Yes, the 27128 should work fine in place of a 27C512.

Spencer 

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[Daniel Quadros]

The 27xxx chips are (AFAIK) EProms, not EEPROMs. To erase them you will need a UV eraser (or leave them under a bright sun for a couple of days). The EEProms are 28xxx (I am using an AT28C64B in my ROM board).

DQ

[Ben Chong]

To use 28C256, you set pin 27 of the ROM to high (normally it's set to 0). Otherwise, it's a direct plug-in.

I used a ZIF socket. So I plug in a normal 28pin IC socket to the one that's soldered on the board, then plug the ZIF socket into that 2nd socket.

The nice thing there is: no risk of damage to the soldered-in socket.

[Derrick Green]

I may look into replacing the standard socket with a Zif socket like the Programer. It is easy to bend pins when removing the chips. I do have a few newly purchased Eproms but will keep in mind how to erase them and cover up the 16K Eproms with electrical tape. I am intreaged with the amount of resources in the web. I still do not quite fully understand how to get CP/M loaded but the Programer will be a good start. Some of the tutorials on smbakers site is a little confusing. I am also thinking about getting the RC2014 SD card board.

[Tom Bruno]

Seems to be pretty common in this group people say the 27C is OTP EPROM. I'm not sure this is true. The AT27C is OTP EPROM but the Wintel W27C512 I have many of and they are all drop in replacements for the AT27C512 and are EEPROM.

[Daniel Quadros]

I stand corrected!

Looks like part numbering for ROMs is a big mess. Back in the 70's 27xxx (2708, 2616, 2732) were UV EPRoms, but there was already differences in voltages and procedures for programming. Now you must lookup the manufacturer datasheet to find out what kind of chip it is. The basic pinout is standard, but an EEProm may replace a NC pin by a Write Enable (looks like the W27C512 uses a special voltage at the OE pin for writing, so you can just plug it in place of the AT27C512 or AT27C512R). And there are also 27F512 and 27E512...

DQ