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W65C02S Address selection

ElectroRetroNerd

Hello World! My name is Kaleb Papesh and I have decided to build my very own 6502 based computer from the ground up after watching the Apple 1 episodes of TBHS. I know that the 6502 is alive and kicking with Western Design Center currently making the chips however, after looking at the data sheets, I don't see any CS or CE lines for me to use a 3-8 decoder to select ram. Has anyone else used a W65C02S chip in there own 6502 based computers? I don't fully understand the entire addressing architecture for the 6502 so if anyone has in depth information on how it works and how to use a 3-8 decoder to select and use ram, the better! Thank you for any help you can provide!

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    In code-space you should put a ZIF socket or sockets.  Here, you can swap between a battery-backed dual-port SRAM for development, perhaps exchanging for a PROM later on.

     

    Remember that you can always insert queue memory to buffer your I/Os if you want a more elastic set-up.

     

    It is common to have Xs in the I/O map to simplify the decoder.  In cheap systems I have fashioned giant nor/nand gates out of wire-or diodes and a mosfet and resistor or two.  Seems crude, but it works.  Requires legit signal diodes, not the universally-loved-in-some-quarters PS diodes.

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    In code-space you should put a ZIF socket or sockets.  Here, you can swap between a battery-backed dual-port SRAM for development, perhaps exchanging for a PROM later on.

     

    Remember that you can always insert queue memory to buffer your I/Os if you want a more elastic set-up.

     

    It is common to have Xs in the I/O map to simplify the decoder.  In cheap systems I have fashioned giant nor/nand gates out of wire-or diodes and a mosfet and resistor or two.  Seems crude, but it works.  Requires legit signal diodes, not the universally-loved-in-some-quarters PS diodes.

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