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A project log for Macintosh SAO

It's the 40th anniversary of the original Macintosh. Why not recapture the magic in an SAO?

aaronAaron 08/07/2024 at 23:180 Comments

I am impatiently waiting the arrival of the components and PCBs that I ordered just a few days ago. While looking back at the last log I wrote, something caught my eye: 

I put silkcreen + and - symbols near the header. And looking at the badge on my desk (shoutout to the Supercon 7 Vectorscope) I realized the position of the pins was wrong. I had the header backwards! Furthermore, I knew how I'd made my mistake:

This is the view of my board from the front (after I corrected it.) Because the front of my board has no components on it I spent most of the time laying stuff out on the back. I think I even did it from the front and wasn't paying attention to the footprint orientation. Whoops! This could have been avoided if I'd used the "official" SAO footprint, but I didn't want the through-hole, so I made my own (I should know better by now.) As I said previously, I have made many PCB mistakes. This one is not huge. When the boards come, I'll still be able to program and test how everything comes together.  And see how it looks visually. It just won't work plugged into a header. I'll respin, and try again.

Since my last project log here, Hackaday officially put Supercon 8 tickets up for sale. In that announcement we learned that this year's badge is going to focus on SAOs! There were some subtle hints about utilizing the whole 6-pin header. As I mentioned previously I included support for the Pins as a target device. However the CH32V003 only has one hardware I2C port and I'm using that for the display.

If I want to support I2C as a target I can either write a software I2C Driver (just bit-banging the protocol) or I could switch to another chip. The step-up from the CH32V003, the CH32V203 has two sets of I2C pins, so I could just switch chips and get that. 

A third option would be to swap out the I2C display for an SPI version,. The displays are the same, but the protocol is different. In this case, I'd need to move from the CH32V003J4M6 to a different package that has a few more pins. 

At any rate, I have some choices to make - and my original boards probably aren't going to arrive for another week.

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