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SMT32L4 USART Vs LPUART Power Consumption

MBrow.13
Associate II

Hi,

We using stdio for debug output in an Mbed OS app. I don't think Mbed OS is particularly relevant to my question. It's just some simple output without flow control or anything fancy.

Currently we're using USART2 for our debug output. USART2 wasn't specifically selected, it just happens to be the default configuration of Mbed OS. It is easy to use LPUART1 instead.

I switched to using LPUART1 and it seemed to work. There also seemed to be a slight reduction in the STM32 current consumption while doing serial output. =)

I just wanted to check if the was anything important that I'm missing. Power consumption is my primary concern.

In particular, I know that LPUART1 can operate in Stop2 mode whereas USART2 is definitely off. I don't want to switch to LPUART1 to save a bit of power while in Run mode without noticing that it is using more power in Stop2 mode. We spend a great more time in Stop2 mode than Run mode.

We're currently using 115200 which I think implies something about how the clocks are configured, although I'm not sure what because we're just using the library configuration. 

Thanks,

Matt

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