Justin DavisI've been looking into UART chips. Even if it's not explicitly stated in my goals, I'd like to recreate the computer design experience of the 1970/1980 era. The first UART chip came out in 1981 (The 8250), so I think it's within the spirit of the project to use its successor the 16550 (specifically the Texas Instruments PC16550D). It has an 8-bit parallel interface and a built-in FIFO. Makes it pretty easy to connect to my data bus. And I can connect the serial side to a UART-USB bridge cable. This will also need a crystal, but I could consider using the same crystal for my system clock (depending on how fast I can run my processor). But I don't think it needs any other chips, so it's a pretty nice addition to my design. I may need one more tri-state chip to interface the control/status lines. I'll have to consider if there's an easier way to do bit-wise interfaces to cut down my chip count.
UART
A project log for One-instruction TTL Computer
A breadboard-able computer which uses only a single instruction - MOVE
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Much earlier than that! "DEC condensed the line unit design into an early single-chip UART for their own use. Western Digital developed this into the first widely available single-chip UART, the WD1402A, around 1971. This was an early example of a medium scale integrated circuit. Another popular chip was the SCN2651 from the Signetics 2650 family." - https://en.wikipedia.org/wiki/Universal_asynchronous_receiver/transmitter#History
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I didn't know any of that. Pretty cool
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