Resolved! Nucleo-F303RE want to set timer source muxes to use PLLCLK*2, to yield 2 * 72 MHz=144 MHz resolution
I'm on Nucleo-F303RE board, which according to the page 129-130 of the reference manual (RM0316 Rev 10) I should be able to set "TIMx (x = 1/2/3/4/8/15/16/17/20) can be clocked from the PLL running at 144 MHz when the system clock source is the PLL a...