I’ve been thinking it would be great to design a replacement front panel for 3rd gen recorders. I already reverse-engineered most of the protocol between the front panel and the microcontroller on the deck (P700/Software/SAMC21N-XPRO/FrontPanelMon/FrontPanelMon/main.c at master · DigitalCompactCassette/P700 · GitHub) and a SPI interface is easy to implement with an Arduino or similar device. And that way you could replace the existing VFD display with graphic LCD and do things like add VU meters and text entry through a keyboard.
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