Shared Projects by autotelic

Adapter to allow use of PLCC32 27C010 in place of DIP 27C128. I have a lot of PLCC32 27C010, this lets them be used for the Fairlight CVI Rev 7 upgrade.

https://github.com/joebritt/Fairlight-CVI-Rev7-Upgrade

Provide 5V power on a USB Type A connector from a 4-pin disk drive Molex connector. Used with modern USB-powered ethernet/WiFi bridge on legacy systems which lack USB.

Nonvolatile FRAM memory replacement for 2332 ROM used by the Rockwell AIM-65. This board plugs into any of the 5 2332 AIM-65 ROM sockets. A lead to the 6502 R/W signal is needed for writing to the FRAM. A Write Protect switch allows disconnecting the R/W signal so that the FRAM truly behaves like a ROM. The FRAM is 8KB, and the 2332 is only 4KB. A switch selected whether A12 is pulled high or low, giving 2 banks of 4KB. A12 may also be tied to an I/O pin, such as from one of the 6522s, to allow programmatic bank selection. See github at: https://github.com/joebritt/AIM-65-FRAM

Stackable breakout debug board for Teensy 3.1/3.2/4.0. Debug header exits at rear. Different Teensy-based projects have different amounts of space around the Teensy itself. Usually the rear of the Teensy is not blocked, since that is where the USB cable connects. TeensySee breaks out the main Teensy signals and provides them on 2x 0.1" headers, suitable for connecting logic analyzer and oscilloscope probes. In addition to the Teensy GND and AGND pins, 2 additional GND pins are provided at the 2-pin header between pins 11/12 and 13/14.

Note the double drills for each of the holes in the Teensy footprint. This is intentional. The board can be assembled for either the more common larger square-pin 0.1" headers OR the smaller round machine-pin header and a machine-pin socket. For the square-pin version, just load stackable (Arduino-style) connectors. For the machine-pin version, load a female machine-pin strip on one side and a male machine-pin strip on the other. I find it helpful to use 2 additional strips plugged at a right angle into each of the strips being soldered. This will hold them at the right spacing and angle. BE SURE TO ORIENT THEM IN THE DOUBLE HOLES THE RIGHT WAY – e.g., both socket strips to the left drills, and both pin strips to the right drills.

This is one of my favorite Forrest M. Mims, III designs from when I was a kid. The venerable LM3914 (meant for digital LED meter applications) and 2 other CMOS ICs drive a TIL305 5x7 LED dot matrix display to make a very simple toy oscilloscope. Even with the low resolution, one can clearly see waveforms like sine, triangle, and square waves. The sweep oscillator is 2 NAND gates wired in a loop with an RC network in the middle. Max frequency with the 100K pot and 0.1uF oscillator is around 1KHz.