2025-09-29

Week of the 09/29/2025 - #40

Contents

tech

Apple 2c Serial Port

art

Text art gallery

Apple 2c Serial Port

I’m investigating how to make an RS-232 <-> MIDI bridge. I think it’s quite simple. I want to connect my Apple 2c serial port to a MIDI device using an Arduino as a bridge. To test this I am analyzing (and checking the timming of my Apple 2c serial port since I know some old Apple 2c’s, like mine, might have timming issues). To test it I’m attaching my logic analyzer to the serial port and do some tests. Here are a couple important links:

Serial port communication on Apple IIc. - This article in c64retr.blogspot.com explains how to configure and send data through the RS-232 ports on the Apple 2c. Since some blog posts tend to sometimes disappear I cloned the article here as a Github gist.
Most common baud rates table - This article shows you the typical timing of RS-232 for different baud rates. The blog has many other interesting resources. Here is the table taken from there:

Most used baud rate table