Decoding CS for OPN2 chip

بواسطة alali.ahmed.t

Master (159)

صورة alali.ahmed.t

21-01-2023, 18:14

I don't have a lot of knowledge on this topic and everytime I try to understand I got confused ????. So, What is the best way to decode for OPN chips? I am just trying to play around with some of the chips I have.

Here are the 2 options I am going to try:

Option 1:

Using 74LS30:

From cartridge slot directly:

A2 to A6, A7/ (inverse) and /IRIQ (inverse) then output to CS


Using 74LS138:

A4, A5, A6, for A, B, C and /A7 (Inverse) for E1. Then E2 or/and E3 iare fed using the following logic:

/WR and /IRIQ fed into 74LS32 that gives output is X1
/RD and /IRIQ fed into 74LS32 that gives output X2

Now: X1 and X2 fes into 74LS08 that gives output fed into E2 or/and E3 of the 74LS138

The output Y of the 74LS138 will be fed to CS of the OPN2

Then we have A0 and A1 directly into the OPN2 chip from the cartridge slot.

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