IO expanders are powered from VCC_FPGA, which can be shut down

MEGA65 / megaphone-r4-pcb

MEGAphone PCB redesign under NLnet Foundation grant

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IO expanders are powered from VCC_FPGA, which can be shut down #74

Open gardners opened 2 years ago

gardners commented 2 years ago

U13 and U14 have power control outputs, and thus these IO expanders should be powered at all times. However, they are powered from VCC_FPGA. Maybe they should be powered from VBAT instead?

gardners commented 2 years ago

We also need to consider the power source for the U24and U31, as these are all on the I2C bus to the OrangeCrab and Xilinx FPGA. The ADC for battery level is already powered from VBAT, so is not a problem here.