Use the CODEC
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How to use the CODEC
The Codec chip is a way to mix and match audio signals together for their single audio output (headphones, RCA jacks).
Its datasheet can be found in the goodies github repo: https://github.com/Mu0n/F256MiscGoodies/blob/main/datasheets/WM8776_v4.1-532420.pdf
Codec Registers
| Address | R/W | B7 | B6 | B5 | B4 | B3 | B2 | B1 | B0 | Purpose |
|---|---|---|---|---|---|---|---|---|---|---|
| 0xD620 | W | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 | Command Low |
| 0xD621 | W | R6 | R5 | R4 | R3 | R2 | R1 | R0 | D8 | Command High |
| 0xD622 | R | X | X | X | X | X | X | X | Busy | Status |
| 0xD622 | W | X | X | X | X | X | X | X | Start | Control |
How to enable (unmute) every sound device
- Loop-read 0xD622 and wait until bit0 is set to 1
- Send 0x1F to Command Low at 0xD620
- Send 0x2A to Command High at 0xD621
- Loop-read 0xD622 and wait until bit0 is set to 1
Audio input devices on the various machines
| CODEC inputs | F256Jr | F256K | F256K2 | F256Jr2 |
|---|---|---|---|---|
| AIN1 | SID | SID | SAM2695 MIDI | SAM2695 MIDI |
| AIN2 | Line in onboard header | OPL3 | MIDI wavetable | |
| AIN3 | PWM | PWM | ||
| AIN4 | VS1053b | VS1053b | ||
| AIN5 | Line in onboard header | Line in onboard header | Line in onboard header |
Here's a precise pinout diagram of the F256K as an example
