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I am using a STM32F412CGU6 and selected PB_9 to be the CAN Tx pin. The pin then idles at 2.8 volts. If I use it as a standard IO pin, it will go to 3.3 volts. If I assign the CAN Tx pin to PA_12 it also idles at 3.3 volts.I am using mbed 5.12