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--- rnd:sketchpad [2024-05-29 18:10] – [Modular radio transceiver] asdf
+++ rnd:sketchpad [2024-10-01 05:10] (current) – asdf
@@ Line 1: / Line 1: @@
 ====== Sketchpad ======
 A home for project ideas that aren't yet fully formed (and which may never be). Those that do survive this gestation phase should receive their own pages, and rejects should probably be retained somewhere.
+===== Teensy softcard for Apple II =====
+Build an Apple II softcard based around the Teensy microcontroller. I'm not yet sure what we'll do with it yet, but we should try to keep as many special pins (the main I2C/SPI buses, maybe a UART bus) free for later use. Maybe one corner of the initial card could be a protoboard, or we could have some of the free pins broken out for jumpers to a breadboard. Sample projects for inspiration:
+  * https://github.com/rallepalaveev/A2DVI/blob/main/v2.0/A2DVI.v2.0.sch.pdf
+  * https://www.tindie.com/products/cvt/esp32-softcard-expansion-card-for-the-apple-ii/
+  * https://www.v2retrocomputing.com/analog (can be used as a VGA output //or// a Z80 softcard!)
+  * schematics and details in the MS SoftCard manual
+We don't yet have a specific use case in mind. Some ideas:
+  * I2C/SPI/UART interface
+  * some kind of audio card/MIDI thing?
+  * ProDOS disk emulation (via SD card)
+  * Z80 softcard
+  * ethernet?
+  * USB bus sniffer
+It may make sense to start with a very simple breakout card and a basic bus sniffer firmware.
 ===== Dual Euclidean trigger/gate module with logic =====