Chained LED Bar V2

Has anyone been able to successfully chain two or more v2 LEB Bars? I’ve modified the GitHub code using the MY9221 datasheet and these examples, which do support chaining: <LINK_TEXT text=“ … src/my9221”></LINK_TEXT>

But I’ve never been able to light more than a single bar.

Thank you for your suggestion. If any user has had similar experience, you can go to github to share, thank you.Regards!

Hi there,

the J3 and J4 are connected to the same signals. So we can connect led1 J2(DO,DCKO,VCC,GND) to led2 J3(DI,DCKO,VCC,GND) and connect led1 to Seeeduino.

you also can connect the led1 J3(DI,DCKO,VCC,GND) to led2 J4(DI,DCKO,VCC,GND) and connect led1 to seeeduino. the led bars will display the same info. thanks.


Thank you, I’m aware of how to chain the modules electrically.

My actual problem is that a) the supplied library does not support chaining (even though the product description specifically mention the module’s chainability) and b) even though I’ve adapted a multi-MY9221 library for use with the Arduino and have thoroughly verified that adaptation against the MY9221 datasheet, I can only get one bar to light. So again, I’m wondering if anyone else (including the manufacturer) has succeeded in chaining these modules, and if so, if they can post the code. (Alpha is OK – I’ll be happy to clean it up and post the result.)

Just to clarify your post, specifically

, I believe you meant to write


Hi there, Yes, you are right. Sorry for my typo. thanks.


It appears that the modules are defective and cannot be chained. Odd, the controller definitely has the option and the required timing is well within the Arduino’s capability. I don’t have an oscilloscope so I can’t see the shifted-out D0 and DCK0 signals, but perhaps one or both aren’t routed from the controller correctly.

If I manage to beg/borrow/steal an oscilloscope I’ll post further information.