Using The Pi Pico As ‘Programmable Hardware’ For The Apple II

August 27, 2024 by Lewin Day 8 Comments

When we think of programmable hardware, we think of FPGAs. But they’re not the only option. [Oliver Schmidt] has been exploring how the Raspberry Pi Pico can serve in such a role for the classic Apple II. The talk was presented at the KansasFest event this year, and it’s well worth diving into!

[Oliver] has developed A2Pico. It’s a series of Apple II peripheral cards that are based around the Raspberry Pi Pico, as you might have guessed. [Oliver] has been working in the area since 2021 with one [Glenn Jones], with the duo experimenting with connecting the versatile microcontroller directly to the slot bus of the Apple II. [Ralle Palaveev] then chimed in, developing the A2Pico hardware with solely through-hole components for ease of assembly.

A number of cards have been developed based on A2Pico, including a storage device, a Z80 CP/M card, and a specialized card to play Bad Apple on the IIGS. It’s all thanks to the versatility of the programmable I/O (PIO) peripheral inside the Raspberry Pi Pico. This device enables the Pico to be reprogrammed to handle all sorts of complicated tasks at great speed. This is particularly useful when using it to bit-bang a protocol or talk with another machine, and it serves perfectly well in this role. Basically, by reprogramming the Pico and its PIO, the A2Pico design can become any one of a number of different add-on cards.

It’s well worth diving into this stuff if you’ve ever contemplated building your own peripheral cards for 8-bit and 16-bit machines. We’ve seen some other great add-on cards for vintage machines before, too.

Continue reading “Using The Pi Pico As ‘Programmable Hardware’ For The Apple II” →

Pi Pico SDR On A Breadboard

August 12, 2024 by Al Williams 25 Comments

How hard is it to make a fully standalone SDR? [101 Things] shows you how to take a breadboard, a PI Pico, and two unremarkable chips to create a capable radio. You can see the whole thing in the video below.

The design uses a standard Tayloe demodulator. There’s also an encoder and an OLED display for a user interface. You might also want to include some PC speakers to get a bit more audio out of the device.

Continue reading “Pi Pico SDR On A Breadboard” →

Mouse Doesn’t Play Pong… It IS Pong!

August 8, 2024 by Al Williams 1 Comment

From the “why didn’t we think of that” department comes [dupontgu’s] pong mouse project. The mouse appears and acts like a normal computer mouse until you click the scroll wheel. When you do, the mouse rapidly moves the cursor on the connected computer to play pong. Obviously, though, the paddles and the ball all look like your cursor, whatever that happens to be. So, how do you tell the score? Well, when a score happens, the cursor shows between the two paddles. In the middle means the game is tied. Otherwise, the player closest to the score indicator is winning. Continue reading “Mouse Doesn’t Play Pong… It IS Pong!” →

Raspberry Has A New Pico, Built With The New RP2350

August 8, 2024 by Elliot Williams 129 Comments

Raspberry Pi’s first foray into the world of microcontrollers, the RP2040, was a very interesting chip. Its standout features were the programmable input/output units (PIOs) which enabled all sorts of custom real-time shenanigans. And that’s not to discount the impact of the Pi Pico, the $4 dev kit built around it.

Today, they’re announcing a brand-new microcontroller: the RP2350. It will come conveniently packaged in the new Pi Pico 2, and there’s good news and bad news. The good news is that the new chip is better in every way, and that the Pico form factor will stay the same. The bad news? It’s going to cost 25% more, coming in at $5. But in exchange for the extra buck, you get a lot.

For starters, the RP2350 runs a bit faster at 150 MHz, has double the on-board RAM at 520 kB, and twice as much QSPI flash at 4 MB. And those sweet, sweet PIOs? Now it has 12 instead of just 8. (Although we have no word yet if there is more program space per PIO – even with the incredibly compact PIO instruction set, we always wanted more!)

Two flavors on the same chip: Arm and RISC

As before, it’s a dual-core chip, but now the cores are Arm Cortex M33s or RISC-V Hazard3s. Yes, you heard that right, there are two pairs of processors on board. Raspberry Pi says that you’ll be able to select which style of cores runs either by software or by burning one-time fuses. So it’s not a quad core chip, but rather your choice of two different dual cores. Wild!

Raspberry Pi is also making a big deal about the new Arm TrustZone functionality. It has signed boot, 8 kB of OTP key-storage memory, SHA-256 acceleration, a hardware RNG, and “fast glitch detectors”. While this is probably more aimed at industry than at the beginning hacker, we’re absolutely confident that some of you out there will put this data-safe to good use.

There is, as of yet, no wireless built in. We can’t see into the future, but we can see into the past, and we remember that the original Pico was wireless for a few months before they got the WiFi and Bluetooth radio added into the Pico W. Will history repeat itself with the Pico 2?

We’re getting our hands on a Pico 2 in short order, and we’ve already gotten a sneak peek at the extensive software toolchain that’s been built out for it. All the usual suspects are there: Picotool, TinyUSB, and OpenOCD as we write this. We’ll be putting it through its paces and writing up all the details next week.

Probably The Cheapest Mac Emulation Hardware

June 20, 2024 by Jenny List 20 Comments

There are many ways to build your own Macintosh clone, and while the very latest models remain a little inaccessible, there are plenty of Intel-based so-called “Hackintoshes” which deliver an almost up-to-date experience. But the Mac has been around for a very long time now, and its earliest incarnation only has 128k of RAM and a 68000 processor. What can emulate one of those? Along comes [Matt Evans], with a working Mac 128k emulated on a Raspberry Pi Pico. Such is the power of a modern microcontroller that an RP2040 can now be a Mac!

The granddaddy of all Macs might have been a computer to lust after four decades ago, but the reality was that even at the time the demands of a GUI quickly made it under-powered. The RP2040 has plenty of processing power compared to the 68000 and over twice the Mac’s memory, so it seemed as though emulating the one with the other might be possible. This proved to be the case, using the Musashi 68000 interpreter and a self-built emulator which has been spun into a project of its own called umac. With monochrome VGA and USB for keyboard and mouse, there’s MacPaint on a small LCD screen looking a lot like the real thing.

If you want a 1980s Mac for anything without the joy of reviving original hardware, this represents an extremely cheap way to achieve it. If it can be compiled for microcontrollers with more available memory we could see it would even make for a more useful Mac, though your Mac mileage may vary.

Of course, this isn’t the only take on an early Mac we’ve brought you.

A C64 SID Replacement With Built-in Games

June 11, 2024 by Alexander Rowsell 9 Comments

Developer [frntc] has recently come up with a smaller and less expensive way to not only replace the SID chip in your Commodore 64 but to also make it a stereo SID! To top it off, it can also hold up to 16 games and launch them from a custom menu. The SIDKick Pico is a simple board with a Raspberry Pi Pico mounted on top. It uses a SID emulation engine based on reSID to emulate both major versions of the SID chip — both the 6581 and the 8580. Unlike many other SID replacements, the SIDKick Pico also supports mouse and paddle inputs, meaning it replaces all functionality of the original SID!

Sound can be generated in three different ways: either using PWM to create a mono audio signal that is routed out via the normal C64/C128 connectors, an external PCM5102A DAC board, or using a different PCB design that has pads for an on-board DAC and TL072 op-amp. While many Commodore purists dislike using replacement chips, the reality is that all extant SID chips were made roughly 40 years ago, and as more and more of them fail, options like the SIDKick Pico are an excellent way to keep the sound of the SID alive.

If you want to hear the SIDKick Pico in action, you can check out the samples on the linked GitHub page, or check out the video below by YouTuber Wolfgang Kierdorf of the RETRO is the New Black channel. To get your hands on a SIDKick Pico, you can follow the instructions on the GitHub page for ordering either bare PCBs or pre-assembled PCBs from either PCBWay or your board manufacturer of choice.

Continue reading “A C64 SID Replacement With Built-in Games” →

The Pi Pico, An SDR Receiver Front End

June 5, 2024 by Jenny List 22 Comments

Making a software defined radio (SDR) receiver is a relatively straightforward process, given the right radio front end electronics and analogue-to-digital converters. Two separate data streams are generated using clocks at a 90 degree phase shift, and these are passed to the software signal processing for demodulation. But what happens if you lack a pair of radio front ends and a suitable clock generator? Along comes [Mordae] with an SDR using only the hardware on a Raspberry Pi Pico. The result is a fascinating piece of lateral thinking, extracting something from the hardware that it was never designed to do.

The onboard RP2040 ADC is of course far too slow for the task, so instead an input is used, with a negative feedback arrangement from another GPIO to form a crude 1-bit ADC. A PIO peripheral is then used to perform the quadrature mixing, resulting in the requisite pair of data streams. At this point these are sent over USB to GNU Radio for demodulating, mainly for convenience rather than necessarily because the microcontroller lacks the power.

The result is a working SDR front end, demonstrated pulling in an FM broadcast station. The Pico has to be overclocked to reach that frequency and it’s more than a little noisy, but we’re extremely impressed with how much has been done with so little. Oddly it isn’t the first Pico SDR we’ve seen, but the previous one was a much more conventional and lower-frequency affair for the European Long Wave band.