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Jacdac Plug-and-Play for Microcontrollers

microsoft.github.io

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Re: Jacdac Plug-and-Play for Microcontrollers

#6

Post by joezydeco »

This popped up three years ago (including on HN) and then disappeared. How did it end up at Microsoft?

https://web.archive.org/web/20191130155328/https://jacdac.or...

I worked with a similar single-wire protocol when working with a large German appliance maker. This looks pretty close to the same idea, they even used PCB edge connectors like this to save a few pennies.

I'll just add that getting the software and hardware right is a lot trickier than it looks. Bus arbitration and collision recovery at the hardware level isn't always the easiest when working with low speed microcontrollers. And, by the time you have it all working, you've reinvented CANBUS but without the differential signalling so you need to keep the cables short.

And all of this is supposed to fit on a single 'cute' board with a pushbutton or tricolor LED? Hardware overkill.

It probably has some use in the hobbyist sector, I'd love to see Sparkfun or Lady Ada pick it up but they're very smart groups and have their own direction with things like Qwiic (which is just I2C, something already on a lot of MCUs in hardware) The proprietary connector, fixed to 3 pins only, is a huge turnoff too. I can get a lot more mileage out of putting FTDI parts on each side of a board and using USB-C patch cords I bought at the gas station.

Re: Jacdac Plug-and-Play for Microcontrollers

#7

Post by a2800276 »

j_leboulanger wrote: post #2

Can you buy the cable ? That seems interesting on the cost side if the cable is not too expensive.

The cable/connector does indeed look interesting, if easily available ... possibly with more pins... I wish they had more details, from the thumbnail[0] they posted of the board edge PCB footprint, I don't see how it could be reversible... The short finger (presumably VDD) would need to be on opposing sides top and bottom, and it's always on the right. Or is my thinking messed up?

[0]: https://microsoft.github.io/jacdac-docs/overview/connectorca...

Re: Jacdac Plug-and-Play for Microcontrollers

#8

Post by jamesadevine »

a2800276 wrote: post #7
j_leboulanger wrote: post #2

Can you buy the cable ? That seems interesting on the cost side if the cable is not too expensive.

The cable/connector does indeed look interesting, if easily available ... possibly with more pins... I wish they had more details, from the thumbnail[0] they posted of the board edge PCB footprint, I don't see how it could be reversible... The short finger (presumably VDD) would need to be on opposing sides top and bottom, and it's always on the right. Or is my thinking messed up? [0]: https://microsoft.github.io/jac…

It is reversible! The reversibility is largely provided by the PCB edge connector as you've identified. More details here [0]

[0] - https://microsoft.github.io/jacdac-docs/ddk/design/#pcb-edge...

Re: Jacdac Plug-and-Play for Microcontrollers

#9

Post by Goz3rr »

progre wrote: post #4
littlevache wrote: post #3

As the XKCD prophecy foretold, there are now 15 competing standards... https://xkcd.com/927/

And the 14 other bus protocols with service advertising aimed at microcontrollers are...?

From the top of my head: SPI, I2C, 1-wire, UART/RS232, RS485, CAN and a bunch more I'm not remembering

Re: Jacdac Plug-and-Play for Microcontrollers

#10

Post by progre »

Goz3rr wrote: post #9
progre wrote: post #4

Earlier quoted context omitted.

And the 14 other bus protocols with service advertising aimed at microcontrollers are...?

From the top of my head: SPI, I2C, 1-wire, UART/RS232, RS485, CAN and a bunch more I'm not remembering

None of those has service advertising (only enumeration). RS232 is not even a buss protocol,
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