As with the other peripherals, at boot the USART peripheral is unpowered. To change this, we must toggle a bit in the appropriate RCC (Reset & Clock Control) register for the bus the peripheral is on.

But what if you don’t have a competent PWM generator? Such was the case that prompted [AnalysIR Blog] to fake it, with USART. Here’s the trick. You set up the serial port to communicate at ten ...