2.00mm to 2.54mm breakou board for 2x20 connector


#1

Hi,

is there a 2.00mm to 2.54mm Adapter board for 96boards planned? The current URAT board seem nice, but it’s not making all the I/O PINs available - in fact it’s actually block them. It would be nice if there is a board for the 2.00mm 2x20 connector giving 2.54mm headers for:

  • dedicated 2x1 headers for:
    SYS_DCIN/GND
    1V8/GND
    5V/GND
    PWR_BTN_N/GND
    RST_BTN_N/GND
  • 10x1 or 2x5 header for GPIO-A to GPIO-L
  • UART0 1x6 header 1V8, GND, RxD, TxD, RTS, CTS (or 2x3 header [GND, RxD, TxD] [1V8, RTS, CTS])
  • UART1 1x4 header 1V8, GND, RxD, TxD
  • I2C0 1x4 header 1V8, GND, SCL, SDA
  • I2C1 1x4 header 1V8, GND, SCL, SDA
  • SPI0: 1x6/2x3 header 1V8, GND, SCLK, DIN, CS, DOUT
  • PCM: 1x6/2x3 header 1V8, GND, FS, CLK, DO, DI

in addition provide a least one USB UART0 (another one for UART0 might be nice) and 2 buttons buttons for Power and Reset. Some LED are a nice add-on

And as a side note, the Mediatek X20 board extends the 2x20 header, so this new breakout board should not block the extended connector’s pins.

Are there any plan to create this?

Axel


#2

Hi Axel

I have a few of these. I bought them from a company called BitWizard. Basically you have to contact them and ask about a customized version of: http://bitwizard.nl/shop/cables-connectors/2mm-to-2.54mm-Adapter-40-Pin-Centered .

Here’s mine:
DIY mezzanine for 96boards

Since they end up being custom made it is a good idea to be extremely explicit about the exact request (e.g. “I’d like a male 2mm connector on the underside of the board and a female/male[1] 2.54mm connector on the top of the board”).

[1] Delete whichever is inappropriate.


#3

Thanks for the answer. I’ve build some stuff on my own that works for me.

Recently, I found this: http://blogs.chris.tylers.info/index.php?/archives/278-Connecting-a-96boards-HiKey-to-a-Breadboard.html
Can be ordered for $12 for the PCB.


#4

@axel I would also suggest you keep an eye on the new Community Mezzanine initiative here: https://github.com/96boards/mezzanine-community

Here you can see that a proto mezzanine is already in the works and ready to be tested for those bold enough to send in for a print.

Please feel free to join us for our meetings, offer ideas through the GitHub issues section and/or clone the repo, consume the template and contribute a board of your own!

Discussions are every Monday at 3:00p UTC on BlueJeans, more information in the repo README.md

Cheers!


#5

Thanks. I’l keep an eye on it. The proto mezzanine look nice, but it’s really missing a breakout of the other UART


#6

The decision to make this protomezzanine without the UART breakout was to push out a quick and easy PCB for a very cheap price. There will be a derivative of this board (soon) that will incorporate the UART breakout :slight_smile: I will try to update this thread when it takes form.

Thanks!


#7

I’m confused. I has one UART breakout? I’m just raising the point that there is a 2nd UART also on the header, which is missing. I’m not a PCB designer, so parson my ignorance - but would it really have been such a pain to put “a few holes” for the other UART there also?

Axel


#8

Actually I saw that and wondered something similar… it looked like there was enough spare space on the right of the board to have a second UART header (although I didn’t look very closely at whether the board trace routings make it hard).


#9

if you are still interested in a 2mm to 2.54 mm you can try to follow this, http://blog.chris.tylers.info/index.php?/archives/278-Connecting-a-96boards-HiKey-to-a-Breadboard.html


#10

Just in case somebody finds this thread looking for a breakout board. Buy the Audio Mezzanine (https://www.96boards.org/product/audio-mezzanine) for $5 form Arrow (https://www.arrow.com/en/products/114990332/seeed-technology-limited). The name is a bit misleading, but it does the job and even has voltage level shifters. It might not fit mechanically on all 96board models due to other components, but that can be fixed.


#11

The audio mezz is awesome although, like the sensors mezzanine it shifts levels during conversion and blocks some of the pins in the 2.54mm header (UART1 is stripped out because the board has on-board FTDI and PCM/I2S is stripped out because supporting with the original design would have required another level shifter chip).

For the record to common hack to make the boards mechanically compatible with non-Dragonboard designs is described here:

Additionally design changes in later revs of the board have resulted in some redundant shifter channels which means (I think) PCM shifting could be added with four hand soldered jumper wires. Having said that the shifters can be sensitive to long cable runs so whether the resulting circuit would actually work isn’t quite clear (at least not based on my relatively meagre analogue skills).