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PiRTC PCF8523 with Multiple I2C
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PiRTC PCF8523 with Multiple I2C

by mengjialyu on Thu Aug 27, 2020 12:10 pm

Dear community,

I am using PiRTC PCF8523 as RTC for my current project which requires several I2C connections/sensors. I plan to mount all the sensors on a perfboard, but am not sure what to do with the PiRTC, as it can only be mounted unto the first 6 pins of Pi. Could someone shed some light on how PiRTC could be mounted on a perfboard or suggest some other possible arrangements?

Thank you,
Mengjia

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Re: PiRTC PCF8523 with Multiple I2C

by adafruit_support_carter on Thu Aug 27, 2020 4:36 pm

Several options:
1. Solder some male headers to the perf board to replicate the same pin pattern as the Pi's GPIO header pins.
2. The connector on the PiRTC has pass thru stackable style holes. You could maybe place the PiRTC on as normal and then access the pins from the top to bring out to your perf board.
3. Use the breakout version instead: https://www.adafruit.com/product/3295

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Re: PiRTC PCF8523 with Multiple I2C

by akamediasystem on Mon Apr 26, 2021 9:54 pm

...I too have many devices on the i2c bus, conveniently connected with Qwiic connectors.

Unfortunately it looks like connecting a PiRTC with PCF8523 will not work, unless I am missing something - when I add the PiRTC to the bus, I see the coin cell quickly draining because it's powering every i2c device's power LED, etc.

Removing the PiRTC's VCC connection entirely (ie, linking the common grounds and hoping the coin cell powers the PCF8523) does not seem to work either, although I am not certain I understand why.

...does anyone else have a successful experience they can share in hooking a PiRTC up to an already-populated i2c bus?

Thanks!

AKA

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