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sb-ocr / ocreeb-mk-2

Modular Macro Keyboard System
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Usage of TCA4307 on each board and staggered connections #10

Open vikavorkin opened 5 months ago

vikavorkin commented 5 months ago

Hi,

First of all, really cool project, thank you for sharing this!

Reading the schematic and the datasheet for the TCA4307 a potential issue arose, the current modules use a single row of pogo connectors for power and communication. Those connectors aren't staggered and don't ensure a consistent order of connection/disconnection.

I'm trying to come up with a simple solution to quite my worries and wanted to ask if you had issues hot swapping the modules? Power issues? Communication issues or lockups?

BeeniGit commented 23 hours ago

Hi,

I searched for the datasheet of these pogo connectors and up to 2A can be supplied into each pin, but I didn't find the connection/disconnection information maybe more than 10.000 (it's make for quick programming of board). So with 4 power pins on the MK2 CORE it's OK (if all of the boards are not connected to the same side...)

@sb-ocr perhaps you could consider using a fuse of 1.5A for each connector it will be a good protection for the future.

As @vikavorkin said in the topic, the normal use of the TCA4307 is to put a component on each new module. The backplane is your MK2 CORE and on each module you put the TCA4307 between the external I2C bus and the ATTINY816 circuit.

image

Normally you should also use a "Staggered Connector" to be protect the module's components. I don't know if it's possible for this project it's just a possible inprovement.