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ZAdamMac / PETI

A project to brute-force-learn embedded product design techniques by creating a 90s-style virtual pet that runs on the MSP430FR5994 microcontroller.
GNU General Public License v3.0
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HW Bug: R3 on REB Rev C causes Low Battery Detection to never work #35

Closed ZAdamMac closed 1 year ago

ZAdamMac commented 1 year ago

The position of Resistor R3 is wrong, and worse, the resistor itself is superfluous.

Because it stands between the Low Battery (LBO) pin on the TPS module and the matched GPIO pin on the microcontroller, the line is constantly pulled high to the level of the main 3.3v rail; that is, the low battery signal is never sent.

By removing this resistor the issue is resolved in f/power-management-enhance's recent commits; using the internal pullup resistor on the MSP430 more than suffices.

Users of revision C development kits should cut resistor R3 off the board or otherwise remove it. TODO: remove from revision D before committing the schematics.

ZAdamMac commented 1 year ago

Fix for this will be included on the Revision D schematics.