Raspberry Pico Adventures

Last post I talked about the amazing PicoVGA library. In this post I talk about my first experiences in using it to implement a text mode that I can use in may serial terminal. The first line is truncated, it turned out I only need to adjust the monitor.

Continuing my search for a way to implement an alphanumeric serial terminal with the Raspberry Pi Pico, I found the extraordinary   PicoVGA  project. It is a very complete library for generating video for VGA monitors, with incredible examples. PicoVGA demo

My first objective in studying video generation with the RP2040 is to construct a serial terminal to use with my retro microprocessor projects (based on Z80, 6502, etc). For this I want an alphanumeric color video with at least 24 rows of 80 characters. I tried to make something alike the CGA/EGA/VGA alphanumeric mode, storing in the video memory the characters code and an attribute byte and generating in real-time the corresponding pixels. This looked something viable with the official solution, but I ended up having a hard time making the basic scheme work and had to settle on 40 columns. It works - in 40 columns

Continuing my experiences with video generation, let's take a look what we got in the official documentation and repositories (notice that the software is marked as "worked in progress"). It works!

One (of many) obvious differences between the Rapsberry Pi Pico and the other Raspberry Pi models is the lack of video output (remember, the Pi Pico is a microcontroller board and the others are single board computers).  Not a big problem! With a few resistors and some ingenious software we can generate video with the Pi Pico. My main interest in this is to build a serial terminal for my retro microprocessor boards (you can see my current effort at  https://github.com/dquadros/RPTerm ). This experiment was done in April 21, based on an article by Dean Belfield . Since then he has improved his hardware and code in many ways, including adding color. Meanwhile I moved on to VGA video .