DIY machine code Forth — Nowadays, one attractive feature of Forth language is that you can start from scratch and write your own Forth. Not many programming languages can claim that, as Forth doesn’t need all the compiler and other layers of incidental complexity from traditional computer software. One kind of DIY Forth is (for…

An Intuitive Understanding — Before the days of digital calipers with LCD display, one learns how to read the Vernier scale on a metal caliper directly. There are still tutorials teaching how to read such a metal caliper correctly. Once you learn how to use the aligned number on the Vernier scale to read…

Send Signal from a Faster to a Slower Clock Domain — 1. Slower to Faster Clock Domain It’s pretty straightforward to send signal from a slower clock domain to a faster clock domain. The basic assumption is that the faster clock can always capture the signal changes, i.e. the edge from low to high or high to low in the slower clock domain, provided that the metastability…

PIO Assembly to Capture Key features of FPGA Verilog code — RP2040 MCU PIO has single clock cycle instruction sets and time delay syntax that make it easy to precisely control IO timing. It almost rivals FPGA in terms of IO control. …

For bitstream configuration and SPI interface to PC — The open source toolchain for ICE40 FPGA works exceptionally well. For example, APIO (link) combines synthesis, simulation and programmer into one easy-to-use CLI, which makes ICE40 FPGAs fun to play with, in strong contrast to bulky, snail-slow Xilinx FPGA toolchains. 1. FTDI SPI Bitstream to Flash Chip Because of the free ICE40 open source toolchain, many low-price…

where PyVISA can’t reach — The standard way to remote control or gather data from digital oscilloscope, DMM, signal generator, etc., is through GPIB/LAN/serial port at the back of these instruments, making connection to the PC. Once the hardware cable is connected, at software level, you need to install some quite large VISA runtime/library. Lastly…

Use Pi as a headless data logger — 1. Goal Rust code was developed on the Windows PC for an experiment setup to collect and visualize real-time data from an embedded system (RP2040 MCU for example). Data is sent over serial/USB connection (FTDI 232H cable) to the PC. …

Piecing Together Embedded Rust Libraries — 1. Hardware LILYGO T-Display RP2040 (https://www.lilygo.cc/products/t-display-rp2040) LILYGO makes nice hardware modules that combine various TFT LCD displays with popular MCUs, such as ESP32 and RP2040. About two years ago, it introduced this T-display module that combines RP2040 (Raspberry Pi PICO) MCU with a ST7789V controlled 1.14" LCD display (135 x 240 pixels).

The FSM Story — Inspired by Tim’s (blog link) FSM theory, I set out to measure a few different WS2812(B) neopixels in the draw. In my previous post (link), I described a 555 timer circuit with its CV (control voltage) pin adjustable via a secondary voltage source. The output pulse of the 555 timer…