Adria is my second attempt to build a simple computer, based on a WDC65C816 CPU.

UART Communication without 6551 or 65C51

Until now I was using a SY6551 ACIA as my serial communications chip for Adria (or Lilith in the past).

As the WDC65C51 has a known issue (stuck RxD bit in status register), I was looking for another solution. I might have found it on the forum.

They mention the NXP SC26C9x as usable solution. I wanted to order these, but by mistake I ordered a NXP SL28L92, which by change, should be a drop-in replacement for the mentioned chip. BUT this one also has a 68000-bus mode, which may make it easier to interface with?

I have just created a new design on a veroboard and I am going to test it, fingers crossed!

While building this testcard, I also noticed I haven’t wired up the /IRQ and /NMI signals to the expansion slots. I have to have a new run of backplanes to have it incorporated in the design.
Also I have to rebuild the templates for Kicad.

Known Issues

(nothing yet)