David Slik's Asynchronous Array of Raspberry Pi Picos, AARPP, Is a Tile-Based RP2040 Supercomputer

Engineer David Slik is working on a microcontroller board with a difference, connecting a grid of RP2040 microcontrollers to create the "Asynchronous Array of Raspberry Pi Picos," or AARPP.

Released late last month, the RP2040 is the first microcontroller and first in-house silicon to be launched by Raspberry Pi — an organization better known for single-board computers. While the launch focused primarily on the Raspberry Pi Pico development board and embeddable module, the RP2040 itself is also to be made available to purchase as a bare chip — something companies from Adafruit to SparkFun have already confirmed they are planning to exploit with a range of in-house RP2040-powered board designs.

Slik's AARPP, though, is unique: It hosts not just one RP2040 chip, but an array of 16 arranged in a 4x4 grid for a total of 32 Arm Cortex-M0+ cores per tile. "Exactly what you need for low-cost data flow/distributed/SIMD [Single Instruction Multiple Data]/Transputer-emulation needs," Slik explains.

The design, as Slik intimates, mimics that of the Inmos Transputer family, launched in the 1980s and designed for highly-parallel computing: A Transputer motherboard would hold an array comprised of multiple CPUs, all communicating with each other and operating in parallel. The same core concept underpins modern GPUs and more esoteric high-performance computing architectures like Tilera, now owned by Mellanox.

"[I] need to do another spin of the board design so that Pi 2040s in the first row can use SWD [Serial Wire Debug] to program/debug North and East Pi 2040s," Slik notes, "and Pi 2040s in every other row can use SWD to program/debug East Pi 2040s. From a software side, I'd use one core for routing/process management/debug/health monitoring/etc, and the second core for running user programs."

Slik has not yet released additional detail publicly, but can be followed on Twitter for more information.