I am using a Beaglebone Black, and I'm trying to implement a minimal bare metal UART app that boots over USB. The purpose here is to learn about the process, so I'm reading the StarterWare code and trying to understand how I would know to do the same.
The problem I'm having is that I cannot figure out the proper clocks to enable to get UART0 to work. If I just enable CM_WKUP_UART0_CLKCTRL, my code hangs when trying to read UART0.UART_SYSC into a register. If I enable CM_PER_UART1_CLKCTRL, everything works. I can't figure out what's going on, or how I would know to enable this clock based on the TRM. I assume the UART1 clock is actually enabling some other clock that I need, but I can't figure out which one it is.
The StarterWare init code for UART0 enables a whole lot of L3 clocks, though I can't tell from the TRM why. The Clock Tree Tool for am335x doesn't help, and I don't currently have access to JTAG.
