In the last two weeks I have made a lot of progress on my Pocket Calculator. Normally, I like to breadboard everything and have it working 100% before I solder anything, but I had to speed things up since I was leaving home where all my electronics stuff is. So far, the project has turned out reasonably well with only a few hiccups.Microcontroller: LPC1114
First of all, I had to get out my old LPC1114s and figure out how to program them again, since I haven't worked with them in over 2 years. Like before, it was really easy to do so with an FT232 cable. After frying an MSP430 Launchpad a few years ago by accidentally giving it 5v from the cable, I was really careful about hooking it up this time. One thing I do is leave the cable unconnected from USB until I recheck all the connections, which saved me this time since I had accidentally plugged into the 5v line again.
Looking on the internet I was surprised to see that no one seems to sell the LPC1114 in DIP28 any more. That means the three that I have left might be the last ones I have to play with. There was some sort of announcement a few years ago that NXP would stop producing the chip then they changed their mind after someone pointed out that the company had promised to keep its chips in production. It looks like they might have decided to stop producing them after all, although they are listed as in production until at least 2022 on the NXP longevity page. One interesting thing I found was a listing for the chip in PLCC44 package with 8KB of RAM instead of the 4 the DIP version has. I'm not sure if those ever made it into production but it would be cool to have one to play with.