FeRAM FM18W08 and 74HC139 decoder with pinouts for SRAM

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Kayumba
Posts: 246
Joined: Sun Mar 01, 2020 2:36 am

FeRAM FM18W08 and 74HC139 decoder with pinouts for SRAM

Post by Kayumba »

Hello community,

I would like to use FeRAM FM18W08 instead SRAM.
Can somebody tell me if it's will be possible to use 74HC139 decoder with same pinouts like for SRAM?
With schematic from https://mousebitelabs.com ( That I will Never stop to thank him for all information on his website)
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For LoROM decoder, pin 7 "1Y3" (EPROM /OE) are also connected to Multiplexers 74HC257D "/OE" pin 15.

I ask you that cause i'he already tried to do it.
When I simply replaced SRAM by FeRAM , I could do saves for LoROM game but not for HiROM.
Then I found a schematic of FeRAM adapter NOR GATE 74HC00D that people use to replace SRAM on original PCB with FeRAM FM18W08.
This schematic should normally work's with both.
But when I tried, this time it's works only for HiROM and not for LoROM. :roll:
https://oshpark.com/shared_projects/vxdehsxC
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Image

Here is my schematic for FM18W08:
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I maybe do something wrong?
Can somebody help me, please?
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