Raspberry Pi Pico

116 Articles

A Pi Pico plugged into a breadboard, with jumpre wires going away from its pins to an SPI flashing clip, that's in turn clipped onto an SPI flash chip on a BeagleBone board

Programming SPI Flash Chips? Use Your Pico!

March 6, 2023 by 10 Comments

At this point, a Pi Pico is equivalent to a bag full of programmers and debugging accessories. For instance, when you want to program an SPI flash chip, do you use one of those wonky CH341 dongles, or perhaps, even a full-on Raspberry Pi with a Linux OS? If so, it might be time to set those two aside – any RP2040 board can do this now. This is thanks to work of [stacksmashing] who implemented serprog protocol for the RP2040, letting us use a Pi Pico with stock flashrom for all our SPI flash chip needs.

After flashing the code to your RP2040 board, all you need to do is to wire your flash chip to the right pins, and then use the serprog programmer type in your flashrom commandline – instructions are available on GitHub along with the code, as you’d expect. Don’t feel like installing flashrom, or perhaps you happen to run Windows and need a flasher in a pinch? [stacksmashing] has a WebSerial-based SPI flasher tool for you, too, and shows it off with a fancy all-the-pinouts board of his own making.

This kind of tool is indispensable – you don’t need to mod one of these CH341 programmers to fix the bonkers 5 V default IO, or keep an entire Linux computer handy when you likely already have one at your fingertips. All in all, yay for one more RP2040 trick up our sleeve – this SPI flashing helper joins an assortment of applets for SWD, JTAG, UART, I2C and CAN, and in a pinch, your Pi Pico will also work as a digital and analog logic analyzer or an FPGA playground.

 

PCB mounted on 3D-printed holder, debug pins attached to Pi Pico on a breadboard. The battery is in the background, disconnected

Reverse Engineering E-Ink Price Tags

February 11, 2023 by 7 Comments

E-ink displays are great, but working with them can still be a bit tricky if you aren’t an OEM. [Jasper Devreker] got his hands on three e-ink shelf displays to reverse engineer.

After cracking the tag open, [Devreker] found a CC2510 microcontroller running the show. While the spec sheet shows a debug mode, this particular device has been debug locked making reading the device’s code problematic. Undaunted, he removed the decoupling capacitor from the DCOUPL pin and placed a MOSFET between it and the ground pin to perform a voltage glitch attack.

A Pi Pico was used to operate the MOSFET over PIO with the chip overclocked to 250 MHz to increase the precision and duration of the glitch. After some testing, a successful glitch pathway was found, but with only a 5% success rate. With two successive glitches in a row needed to read out a byte from the device, the process is not a fast one. Data pulled so far has shown to be valid code when fed into Ghidra, and this project page is being updated as progress continues.

If you want to delve further into hacking e-ink price tags, checkout this deep dive on the topic or this Universal E-paper Sniffer.

Old 3D CAD Mouse Gets New Lease Of Life

February 7, 2023 by 11 Comments

[Jacek Fedorynski] had an old Magellan/SpaceMouse 3D mouse with a serial interface which made it impossible for him to use with modern hardware and software. The problem he faced was two pronged – the absence of serial interfaces in the hardware and the lack of appropriate drivers for the operating system. So he built a low cost, simple adapter to use his RS-232 Magellan/SpaceMouse with modern software.

The hardware required to build the adapter was minimal. A Raspberry Pi Pico, a MAX3238 based RS-232 adapter, a null modem adapter and a DB9 gender changer. Of course, a combination null modem – gender changer would have made things even simpler. Four of the GPIO pins from the Pico are mapped to the serial RX, TX, RTS and CTS pins.

On the software side, the code emulates a 3DConnexion SpaceMouse Compact, so it can be used with software like Fusion 360, 3ds Max, SolidWorks, Inventor, Maya and many others. On the host computer, only the standard 3DxWare driver package is needed. On the host computer, the old Magellan/SpaceMouse 3D will appear like a modern SpaceMouse Compact connected over USB. The only downside to this is that the SpaceMouse Compact has just two programmable buttons, so only two of the many buttons on the old Magellan mouse can be mapped.

Flashing the code to the Pico is also straightforward using the BOOTSEL mode. Hold down the BOOTSEL button when plugging in the Pico and it appears as a drive onto which you can drag a new UF2 file. Just drag-n-drop [Jacek]’s magellan.uf2 firmware and you’re done.

If you’d rather build your own, modern 3D mouse, check out the DIY Cad Mouse You Can Actually Build.

Building A Fake Printer To Grab Screenshots Off The Parallel Port

February 3, 2023 by 36 Comments

[Tom Verbeure] recently found himself lamenting the need to take screen grabs from an Advantest R3273 spectrum analyzer with a phone camera, as the older gear requires you to either grab tables of data over an expensive GPIB interface card, or print them to paper. Then he realized, why not make a simple printer port add-on that looks like a printer, but sends the data over USB as a serial stream?

On the hardware side, the custom PCB (KiCAD project) is based on the Raspberry Pi Pico. Obvious form factor issues aside ([Tom] did revise the PCB to make it smaller) this is a shrewd move, as this is not a critical-path gadget so using the Pico as a USB-to-thing solution is a cost-effective way to get something working with minimal risk. One interesting design point was the use of the 74LVC161284 special function bus interface that handles the 5 V tolerance that the RP2040 lacks, whilst making the project compliant with IEEE-1284 — useful for the fussier instruments.

Using the service manual of the Sharp AP-PK11 copier/printer as a reference, [Tom] again, shows how to correctly use the chip, minimizing the design effort and scope for error. The complete project, with preliminary firmware and everything needed to build this thing, can be found on the project GitHub page. [Tom] does add a warning however that this project is still being worked on so adopters might wish to bear that in mind.

If you don’t own such fancy bench instrumentation, but grabbing screenshots from devices that don’t normally support it, is more your thing, then how about a tool to grab Game Boy screenshots?

Picture of the dumper board, with a ROM chip and a Pi Pico inserted

A Disposable Dumper For ROM Chips With A Pi Pico

February 2, 2023 by 26 Comments

ROM dumping is vital for preserving old hardware, and we’ve seen many hacks dedicated to letting someone dump a ROM and send its contents to some hacker stuck with a piece of technology that lost its firmware. However, that requires ROM dumping tools of some kind, and it’s often that the lucky ROM-equipped hacker doesn’t own such tools. Now, you could mail the chip to someone else, but postal services in many countries are known to be UDP-like — lossy and without delivery guarantees. The risk of leaving both hackers without a ROM chip is quite real, so, instead of mailing ROM chips or expensive devices around, [Amen] proposes a cheap and disposable flash dumping tool that you could mail instead.

The ROMs in question are 24-pin 2332 and 2364 chips, which run at 5 V and can easily be read with any microcontroller. Thus, his concept is a very simple board, with a Pi Pico and flash chip socket on it, as well as some resistors. Those are used to provide rudimentary GPIO over-voltage protection, since the RP2040 runs its GPIOs at 3.3 V. All the magic is in the software – the tool can both write the chip contents in the RP2040’s internal memory, as well as dump it over USB to the computer. Everything is open-source – if you ever need to dump a rare chip on the other side of the world, modify the design to your liking, order a few copies and then mail them to the hacker involved – losing such a package is way less significant than losing a ROM chip with last-of-its-kind firmware on it.

Old ROM chips are dying out, causing whole generations of hardware, like synths, to fade away – with tools like this one, you can lend a hand in preserving the legacy of many an industry and hobby, and many hackers do. Looking to learn about the basics of parallel flash dumping? This post from 2012 will be a good start, and then check out a more recent venture to learn how things are done with more recent parts.

Generating PAL Video With A Heavily Overclocked Pi Pico

January 24, 2023 by 19 Comments

Barely a week goes by without another hack blessing the RP2040 with a further interfacing superpower. This time it’s the turn of the humble PAL standard composite video interface. As many of us of at least a certain vintage will be familiar with, the Phase Alternate Line (PAL to friends) standard was used mainly in Europe (not France, they used SECAM like Russia, China, and co) and Australasia, and is a little different from the much earlier NTSC standard those in the US may fondly recollect. Anyway, [Fred] stresses that this hack isn’t for the faint-hearted, as the RP2040 needs one heck of an overclock (up to 312 MHz, some 241% over stock) to be able to pull off the needed amount of processing grunt. This is much more than yet another PIO hack.

The dual cores of the RP2040 are really being pushed here. The software is split into high and low-level functions, with the first core running rendering the various still images and video demos into a framebuffer. The second core runs in parallel and deals with all the nitty-gritty of formatting the frame buffer into a PAL-encoded signal, which is then sucked out by the DMA and pushed to the outside world via the PIO. There may be a few opportunities for speeding the code up even more, but [Fred] has clearly already done a huge amount of work there, just to get it working at all. The PIO code itself is very simple but is instructive as a good example of how to use multiple chained DMA channels to push data through the PIO at the fastest possible rate.

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From A 6502 Breadboard Computer To Lode Runner And Beyond

January 17, 2023 by 2 Comments

As disruptive and generally unpleasant as the pandemic lockdowns of 2020 were, they often ended up being a catalyst for significant personal growth. That was often literal growth, thanks to stress eating, but others, such as [Eric Badger], used the time to add skills to his repertoire and build a breadboard 6502 computer and so much more.

For those of you looking for a single endpoint to this story, we’re sorry to disappoint — this isn’t really one of those stories. Rather, it’s a tale of starting as a hardware newbie with a [Ben Eater] 6502 breadboard computer kit, and taking it much, much beyond. Once the breadboard computer kit was assembled, [Eric] was hooked, and found himself relentlessly expanding it. At some point, he decided to get the classic game Lode Runner going on his computer; this led to a couple of iterations of video cards, including a foray away from the breadboards and into PCB design. That led to a 6502 emulator build, and a side quest of a Raspberry Pi Pico Lode Runner appliance. This naturally led [Eric] to dip a toe into the world of 3D printing, because why not?

Honestly, we lost track of the number of new skills [Eric] managed to add to his toolkit in this video, and we’re sure this isn’t even a final accounting — there’s got to be something he missed. It’s great stuff, though, and quite inspirational — there’s no telling where you’ll end up when you start messing around with hardware hacking.

Continue reading “From A 6502 Breadboard Computer To Lode Runner And Beyond” →