Raspberry Pi

1835 Articles

a Pi Pico on a breadboard, running a 7-segment counter gateware, with a 7-segment digit and a pushbutton next to the Pico

Want To Play With FPGAs? Use Your Pico!

December 31, 2022 by 21 Comments

Ever want to play with an FPGA, but don’t have the hardware? Now, if you have one of those ever-abundant Pi Picos, you can start playing with Verilog without getting an FPGA board. The FakePGA project by [tvlad1234], based on the Verilator toolkit, provides you with a way to compile Verilog into C++ for the RP2040. FakePGA even integrates RP2040 GPIOs so that they work as digital pins for the simulated GPIOs, making it a significant step up from computer-aided FPGA code simulation

[tvlad1234] provides instructions for setting this up with Linux – Windows, though untested, could theoretically run this through WSL. Maximum clock speed is 5KHz – not much, but way better than not having any hardware to test with. Everything you’d want is in the GitHub repo – setup instructions, Verilog code requirements, and a few configuration caveats to keep in mind.

We cover a lot of projects where FPGAs are used to emulate hardware of various kinds, from ISA cards to an entire Game Boy.  CPU emulation on FPGAs is basically the norm — it’s just something easy to do with the kind of power that an FPGA provides. Having emulation in the opposite direction is unusual,  though, we’ve seen FPGAs being emulated with FPGAs, so perhaps it was inevitable after all. Of course, if you have neither a Pico nor an FPGA, there’s always browser based emulators.

Continue reading “Want To Play With FPGAs? Use Your Pico!” →

Logic Gate Game Is Fun AND Educational

December 30, 2022 by 1 Comment

How well do you know your logic gates? For their final submission for STEM Projects class, [BKriet] gamified the situation using a Raspberry Pi Pico, some blinkenlights, and a not-insignificant amount of 3D printing. The result is Name! That! Gate!, a fun and educational toy that [BKriet] ultimately donated back to the class (that’s a hot move in our book).

The objective of this game is to figure out which logic gate is being used to make the output shown on the screen, given A, B, and/or C as inputs. There are ten stages to the game, and each correct stage awards the player 14 points, for a perfect score of 140. Although a random gate is loaded for every stage, code ensures that no gate is ever repeated during a single game.

This project is completely open source, so the gate is wide open. Don’t have a 3D printer? Here’s a big set of PCB logic gates, but really, you can make logic gates out of almost anything.

Pi-Cast Adds ATX Signalling To KVM

December 29, 2022 by 14 Comments

A KVM is a great tool for administering a number of different computers without cluttering one’s desk with extra peripherals, or for having to re-connect the keyboard, video, and mouse to each new machine as needed. For local administration this can save a ton of time and headache. For remote administration, though, a virtual KVM is needed, and although these solutions are pricey it’s possible to build one around a Raspberry Pi for a fraction of the cost. This one adds even more functionality by also switching the ATX signals from the motherboard and simplifying cable management to boot. Continue reading “Pi-Cast Adds ATX Signalling To KVM” →

Showing a board with a Pi Pico plugged into it, a USB-A socket marked "USB host", and a character display that says "PASSED" referring to the board being the brains of a testing jig.

USB Host On RP2040 – With PIO

December 28, 2022 by 11 Comments

Folks from [Adafruit] are showing off a neat hack – USB host on RP2040, using the now-famous PIO peripheral. [Adafruit] builds a lot of RP2040 boards, and naturally, you gotta test them before you ship them to customers. They’ve been using very specific Teensies for that, and at some point, those became unobtainium. Based on the work of [sekigon-gonnoc] and with help of [Thach], they’ve made their TinyUSB library support bitbanging of USB over PIO, and successfully ported their test jig firmware to it!

The base Pico-PIO-USB repo by [sekigon-gonnoc] shows a pretty impressive state of affairs – with low-speed and full-speed USB host and full-speed USB device modes supported, and quite a few examples to get you started. [Adafruit]’s work integrates this code into their TinyUSB stack, specifically focusing on MST (mass storage) features – as this is what you need to program a RP2040. Of course, they also provide a mass storage example to boot!

Test jigs are pretty important to have when making multiple pieces of a board, and with RP2040 supporting more and more interfaces thanks to PIO, it sounds like the perfect chip for your next production testing-intended PCB. With the jig brains taken care of, you’ll want to look into building no less important mechanical part, and we’ve covered quite a few ways to sort that out – here’s an OpenSCAD script that generates lasercutting files out of KiCad boards, or a jig built out of scrap copperclad FR4, and a pretty extensive tutorial on making your own lasercuttable jigs, to boot.

Continue reading “USB Host On RP2040 – With PIO” →

Giant Spinning POV Christmas Tree

Spinning Holographic POV Christmas Tree Of Death

December 27, 2022 by 11 Comments

[Sean Hodgins] really harnessed the holiday spirit to create his very own Giant Spinning Holographic Christmas Tree (of Death). It’s a three-dimensional persistence-of-vision (POV) masterpiece, but as a collection of rapidly spinning metal elements, it’s potentially quite dangerous as well. As [Sean] demonstrates, the system can display other images and animations well beyond the realm of mere holiday trees.

Initial experiments focused on refining the mechanical structure, bearings, and motor. A 1/2 horsepower A.C. motor was selected and then the dimensions of the tree were “trimmed” to optimize a triangular frame that could be rotated at the necessary POV speed by the beefy motor.  A six-wire electrical slip ring allows power and control signaling to be coupled to the tree through its spinning central shaft.

The RGB elements are SK9888 LEDs also know as DotStar LEDs. DotStar LEDs are series-chainable, individually-addressable RGB LEDs similar to NeoPixels. However, with around 50 times the pulse width modulation (PWM) rate, DotStars are more suitable for POV applications than NeoPixels.  The LED chain is driven by a Raspberry Pi 4 single board computer using a clever system for storing image frames.

If deadly rotational velocity is not your cup of tea, consider this slower spinning RGB Christmas tree featuring a DIY slip ring. Or for more POV, may we suggest this minimalist persistence-of-vision display requiring only a few LEDs and an ATtiny CPU.

Continue reading “Spinning Holographic POV Christmas Tree Of Death” →

Roll Your Own WiFi Driver For The Pico W

December 13, 2022 by 28 Comments

The Raspberry Pi Pico is a handy little microcontroller that has become a widespread addition to many hackers’ workbench. The Pico W has a CYW4342W module (just like the Pi Zero W) to add WiFi capabilities and [Jeremy Bentham] ported his bare-metal WiFi driver to the Pico W.

The CYW43438 is an SDIO interface, so most of the code ported over from his Zerowi project, but there were a few notable tweaks along the way. Given that the Pi Pico SDK has the complete source code to drive the CYW43439 with an open source TCP/IP stack (lwIP) and the datasheets from Infineon are pretty detailed, why create your own driver?

The short answer is…because why not. But a second answer is to tweak it just how you like it. With his own implementation, [Jeremy] can focus on maximizing throughput and making WiFi a little easier to debug. He deeply delves into the hardware, scope traces, and code samples. It’s a tremendous five-part read over lunch. Some highlights include writing some code for the PIO (Programmable I/O) to interface with the SPI interface, bank switching in the WiFi RAM, handling the 140 different events, connecting to a network, and sending pings.

The PicoWi code is available on GitHub. Perhaps it can be integrated with this PCMIA interface to offer outstanding performance to an older laptop.

side by side, showing hardware experiments with capacitor gating through FETs, an initial revision of the modchip board with some fixes, and a newer, final, clean revision.

A Modchip To Root Starlink User Terminals Through Voltage Glitching

November 28, 2022 by 36 Comments

A modchip is a small PCB that mounts directly on a larger board, tapping into points on that board to make it do something it wasn’t meant to do. We’ve typically seen modchips used with gaming consoles of yore, bypassing DRM protections in a way that a software hacks couldn’t quite do. As software complexity and therefore attack surface increased on newer consoles, software hacks have taken the stage. However, on more integrated pieces of hardware, we’ll still want to return to the old methods – and that’s what this modchip-based hack of a Starlink terminal brings us.

[Lennert Wouters]’ team has been poking and prodding at the Starlink User Terminal, trying to get root access, and needed to bypass the ARM Trusted Firmware boot-time integrity checks. The terminal’s PCB is satellite-dish-sized, so things like laser fault injection are hard to set up – hence, they went the voltage injection route. Much poking and prodding later, they developed a way to reliably glitch the CPU into verifying a faulty firmware, and got to a root shell – the journey described in a BlackHat talk embedded below. Continue reading “A Modchip To Root Starlink User Terminals Through Voltage Glitching” →