2021-06-17 10:47 AM
I'm currently using the STM32 L476RG for an application where I need to communicate with peripherals through SPI at 1.8V. Currently I'm using the TXB0108 bidirectional logic level shifter to convert my SPI lines from 3.3V to 1.8V but there are problems with signal integrity since the ICs are daisy chained. When I supply 1.8V to the VDD pin and power the MCU externally the SPI communication problems go away.
My question is if I were to go with this solution, are there any other considerations I should we worried about when lowering the voltage level? I need to run the MCU at 80 MHz, is that still possible?
Thank you
2021-06-17 10:56 AM
>>is that still possible?
Surely the Data Sheet indicates that?
The core itself runs at 1.2V, the thing which slows would be the flash
USB IO would need a different supply.
2021-06-17 11:07 AM
Thank you! I couldn't find anything that mentioned that in the data sheet but if you could point my in the right direction that'd be great.
Also, would the ADCs now operate relative to 1.8V?
2021-06-17 11:48 AM
ADC's reference is VREF+ pin, which in your 64-pin package is probably connected to VDDA; and VDDA can be set higher than VDD in 'L4.
JW