PSG Register R10

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The envelope shape/cycle control is contained in the lower 4 bits of register R10. Each of these 4 bits controls a function in the PSG Envelope Generator:

  • b3: Continue
  • b2: Attack
  • b1: Alternate
  • b0: Hold

Note: The envelope is reseted each time R10 is overwritten (even if it's with the same value).

Below are the different possible shapes, according to R10 bits:

R10 bitsEnvelope generator output
00xxEnvShape00xx.png
01xxEnvShape01xx.png
1000EnvShape1000.png
1001EnvShape1001.png
1010EnvShape1010.png
1011EnvShape1011.png
1100EnvShape1100.png
1101EnvShape1101.png
1110EnvShape1110.png
1111EnvShape1111.png