Posted on June 25, 2018 at 00:59Am am using an STM32L433 part with an LSE and wish to use the LSCO to drive a Bluetooth module's low-power oscillator input (SPBT3.0DP2's LPO) pin. I see that the code which enables the LSCO output sets the PA2 to Analog mode. I am running the MCU at 3.3V. The BT module LPO limits are 1.5-1.8V. So I need to do some sort of level conversion. After reading the reference manual and datasheet, I still don't have a good feel for the electrical characteristics of the L4's LSCO pin.
Is the output impedance characterized somewhere? I don't see that in the datasheet or reference manual.
What is the affect of setting an output pin which is not driven by the DAC to analog mode?
I am asking because I am trying to find the lowest cost and lowest power option for driving the LPO at 1.8V. The BT module does have a 1.8V output which can be switched via a mosfet if needed, but I don't know yet♯ if I really need an active component here.
#stm32l4 #lsco
