STM32F030 outputs 1.3V instead of 3V

[CeeLazzy]

I have set all GPIOB ports as outputs and have an adjustable resistor on port PA1 which I’ve set as an analogue input to do an adc conversion to display a voltage output to three seven segment displays with each segment being connected from PB0 to PB6 however it seems my port B pins are not outputting a voltage of 3V when set to high. All ports are set as pull downs internally. What could be the reason for this?

[Tesla DeLorean]

A schematic might be more enlightening rather than having to guess what's wrong.

Perhaps you've missed half the power pins, ignored the analogue power pins, or got some grounding issue?

Check you netlist, make sure you don't have random islands of connectivity due to mismatches at a naming level for different/same nets.

Pin level conflicts, shorts, two outputs connected and driving in different directions?