Very nice. I am wondering -- why have a devboard this small?

This looks awesome, I'd love to get one. Question, what's the advantage over something like the ESP32C3 and the like? Just even smaller?

I'm interested in this too. I've been using STM32 NUCLEO boards, which are cheap and capable, but even the smallest ones are noticeably larger than this. I'd love to see an STM32 version of this project.

Very nice. I am wondering -- why have a devboard this small?

...trust me this is the best USB cord ever try it out for free, ill sell you some cheap if you get a couple friends to buy some.

https://shop.hak5.org/products/omg-cable

https://phreakboutique.com/blogs/tutorials/using-your-new-ev...

thats how the grift starts...

This looks awesome, I'd love to get one. Question, what's the advantage over something like the ESP32C3 and the like? Just even smaller?

If it helps, I've used earlier Atmel AVR chips, as well as the ESP32-S3.

8-bit AVR is an extremely clean, relatively simple instruction set that can be viably hand-coded. It's fairly straightforward to calculate the exact number of cycles your code will use, which is handy for applications requiring deterministic timing and for knowing worst-case execution time of interrupt handlers.

If the C3 instruction set is anything like the S3, I'm willing to bet it's not as straightforward.

Atmel also tends to do a better job of their documentation. I've lost count of how many confirmed errata I've reported to Espressif, and the time (and steam) I lost troubleshooting them in the first place.

I like the S3, and it's heaps powerful, but for small projects that don't need advanced peripherals like Wifi, DMA, etc. I can envision that AVR as being a fine choice.

It isn't necessarily smaller. See https://github.com/PegorK/f32

It's a much less fancy cpu that's very small. No wireless. Lower powered I would expect. But it's an MCU with something like 16KB of flash and 2KB of ram if I remember right. The analog stuff on it is supposed to be pretty good. The Anduril flashlight firmware (toykeeper.net/anduril) is a somewhat popular application that can run on it.

...trust me this is the best USB cord ever try it out for free, ill sell you some cheap if you get a couple friends to buy some.

https://shop.hak5.org/products/omg-cable

https://phreakboutique.com/blogs/tutorials/using-your-new-ev...

thats how the grift starts...

That's it, I'm going back to parallel port cables for everything now.

AngstromIO-devboard

AngstromIO is one of the smallest devboards out there, barely longer than a USB-C connector, based on the Attiny1616 MCU. 2 GPIOs as well as I2C lines are broken out. I made a dual CH340 programming board too, both for UPDI programming and debugging (one way Serial Communication). I also designed a breadboard friendly, experimentation board for the CH32V003, with a 4 by 5 charlieplexed LED matrix.

While the AngstromIO is a tiny devboard, yet powerful, that could be embbeded in any space constrained projects, the CH32 devboard is more an experimentation board, for me to learn how to program this awesome chip on the MounriverStudio programming and how to program a charlieplexed matrix. The Programmer is an all in one module, that will make debugging with the Serial monitor while programming easy: one board for both.

Key features:

AngstromIO Key features:

One of the smallest devboards: 8.9mm by 9mm, USB-C included
Attiny1616 MCU, 16Kb flash, low power, arduino compatible (for basic libraries at least)
USB-C for power, runs at 5V
2x RGB addressable LEDs (SK6805-EC15)
Pins broken out: SCL, SDA, PB2 (TX), PA3, +5V, GND, and UPDI for programming

Programmer Key features:

Dual CH340E setup:
- One for programming (set as SerialUPDI programmer),
- One for debugging (Serial Communication, USB to UART)
2 USB-C for data transfer, only the USB-C for Serial provides 5V to the board
On board 3.3V LDO
3.3V/5V operating voltage selection

CH32 devboard Key features:

Breadboard friendly devboard
cheap 25cents CH32V003, Risc-V MCU, 26Kb flash
USB-C for power, the CH32 runs at 3.3V but PC6 and PC5 are 5V tolerant
On board 3.3V LDO
4x5 charlieplexed LED matrix
SWIO programming, proper programmer required (WCH linkE)

Pinout:

Software:

AngstromIO Software:

Arduino compatible, some libraries may not work, but some have been arranged/made by SpenceKonde like Wire (I2C) and tinyNeoPixel (for more information, see: https://github.com/SpenceKonde/megaTinyCore/tree/master/megaavr/libraries)

CH32 devboard Software:

Programmed on the Mounriver studio IDE

PCB design:

PCB designed in EasyEDA Pro, 2 layers, 1.0mm thick, Purple soldermask All 3 designs panelized into one PCB.

Schematic:

PCB Layout:

panel front

panel back

Programmer PCB 2D CH32 Devboard top CH32 Devboard btm

Renders:

🚧 to be continued...

BOM:

AngstromIO BOM:

🚧 coming soon...

Programmer BOM:

🚧 coming soon...

CH32 devboard BOM:

🚧 coming soon...

It isn't necessarily smaller. See https://github.com/PegorK/f32

If it helps, I've used earlier Atmel AVR chips, as well as the ESP32-S3.

If the C3 instruction set is anything like the S3, I'm willing to bet it's not as straightforward.

I like the S3, and it's heaps powerful, but for small projects that don't need advanced peripherals like Wifi, DMA, etc. I can envision that AVR as being a fine choice.

> If the C3 instruction set is anything like the S3, I'm willing to bet it's not as straightforward.

Its not, not really anyway. The Xtensa LX7 in the S3 is very weird, though also quite fun to play with. The C3 is RISC-V

I'll second this.

Doing asm on the AVR is beautiful, you can count clock cycles easily and then observe them on the scope.

I wrote a bit banging serial interface for an AVR once and had a mystery when I was testing it from a PC just with a basic echo. Every Nth character would be wrong. Was able to figure out a timing problem by counting clock cycles and found the bug in my code.

Was cool to see it align with what I was seeing on my oscilloscope.

> Lower powered I would expect

With the right software, ESP32 can be incredibly low power. Like "months on 3xAA batteries" for watching a pin with the ultra low power subsystem and then occasionally waking up and making a HTTPS call over WiFi.

That's it, I'm going back to parallel port cables for everything now.

The parallel port (at least in it's later implementations) actually supports DMA - I'm sure that data exfiltration via the parallel port is hard, but probably not impossible...

Nothing is safe, unfortunately!

I'll second this.

Doing asm on the AVR is beautiful, you can count clock cycles easily and then observe them on the scope.

Was cool to see it align with what I was seeing on my oscilloscope.

> If the C3 instruction set is anything like the S3, I'm willing to bet it's not as straightforward.

Its not, not really anyway. The Xtensa LX7 in the S3 is very weird, though also quite fun to play with. The C3 is RISC-V

Thanks for correcting me. Are there any good, small "Hello World" examples of RISC-V programming with the C3 you can point me to? I'd love to get a sense of how it compares in practice.

> Lower powered I would expect

The parallel port (at least in it's later implementations) actually supports DMA - I'm sure that data exfiltration via the parallel port is hard, but probably not impossible...

Nothing is safe, unfortunately!

The parallel port controller can DMA, that lets the driver tell the port hey, send this buffer out to the port and let me know or read this many bytes into this buffer and let me know. It's not peripheral controlled DMA like with firewire or PCI.

You can absolutely exfiltrate data via the parallel port... that's why you attach printers or zip disks... it's just that it needs host participation.

It’s almost certainly impossible on modern systems. The southbridge which allowed DMA to parallel port was absorbed into PCH and slowly stripped of legacy LCP support by chipset and motherboard manufacturers.

Thanks for correcting me. Are there any good, small "Hello World" examples of RISC-V programming with the C3 you can point me to? I'd love to get a sense of how it compares in practice.

You can absolutely exfiltrate data via the parallel port... that's why you attach printers or zip disks... it's just that it needs host participation.

Hacker Times

Hacker Times

PCB devboard the size of a USB-C plug

Discussion

Discussion

AngstromIO-devboard

Key features:

AngstromIO Key features:

Programmer Key features:

CH32 devboard Key features:

Pinout:

Software:

AngstromIO Software:

CH32 devboard Software:

PCB design:

Schematic:

PCB Layout:

Renders:

BOM:

AngstromIO BOM:

Programmer BOM:

CH32 devboard BOM: