Retro CPC Dongle – Part 27

After a two month absence, I can reveal that the CPC2 has another component almost ready for prime time. The past few weeks have been spent writing the Verilog RTL code for the uPD765 floppy disk controller, from scratch. It was one of the more interesting and sophisticated functions that I’ve written. Take a look at this “proof of life”:

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ESP32 Bluetooth: Using the BTstack library

Mad props to antepher and his awesome techtutorialsx blog. Just when I’d given up hope that the ESP32 would resolve my Bluetooth woes, he points out that BTStack is a pretty capable stack for embedded and has a port for the ESP32 already! I’m eternally grateful…thank you! More to come, but I may be able to get the ESP32+BTStack to connect to my Bluetooth HID devices for CPC2…

techtutorialsx

The objective of this ESP32 tutorial is to explain how to get started with the Bluetooth functionalities that are supported by the ESP32 hardware. The Bluetooth tests of this tutorial were performed using a DFRobot’s ESP-WROOM-32 module, integrated in a ESP32 FireBeetle board.

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Retro CPC Dongle – Part 25

What’s wrong with this picture? (Impedance matching and other things)

It’s about time we talked about high speed signals, impedance matching and signal reflections.  Take a look at this picture:

(Very) close up view of the captured CPC screen

There is something clearly wrong with the image above, the pixels are all there and the colours are almost right, but what you’re seeing above isn’t what was sent from the FPGA. What I think I’m seeing here is signal trace length skew and signal reflections.

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