Author Topic: rom 23C128 TO 27C128 ADAPTER  (Read 989 times)

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Offline DaxxinTopic starter

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rom 23C128 TO 27C128 ADAPTER
« on: January 13, 2019, 08:06:10 am »
Any schematic about this adapter?
 

Offline johnkenyon

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Re: rom 23C128 TO 27C128 ADAPTER
« Reply #1 on: January 13, 2019, 02:47:39 pm »
Might be an idea to tell us where/how you are planning to use the adaptor.

Note that the chip select/enable(s) on 23C128 were defined active high or low along with the ROM mask, and can have more than one chip select. (For example: http://hardware.speccy.org/datasheet/23c128.pdf )

One example is the ZX Spectrum - which effectively had two active low chip selects plus output enable - in this case it is better to mod the PCB to synthesise a nCE signal using a pair of diodes, and use the existing socket. (See: https://spectrumforeveryone.com/technical/fitting-eprom-48k-spectrum/).


« Last Edit: January 13, 2019, 02:55:24 pm by johnkenyon »
 


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