AN4635 datasheet(14/34 Pages) STMICROELECTRONICS

14 / 34 page

Power consumption comparison

AN4635

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DocID027290 Rev 1

Power consumption comparison

All the pictures in this section show the detailed measurement of differently configured

STM32L0-Nucleo running the following routine, graphically illustrated in Figure 1:

Run mode in waiting loop – showing the regular power consumption.

Transmission of 100 byte message.

Idle state 10 ms: Stop or Sleep mode waiting for reply (depending on configuration).

Reception of the same 100 bytes.

Compare the message to detect communication errors and go back to 1.

Figure 1. Test loop description

The device starts running full speed in the loop to showcase the regular power consumption

on its clock configuration. This is followed by approximately 100 ms of 9600 baud

transmission, then 10 ms of idle state, waiting for incoming reply. Only 2 measurements

feature the higher communication speed of 57600, where the communication phases 2 and

4 are significantly shorter. Receiving the reply then takes another 100 ms.

Both the transmission and reception usually consumes less power than the regular run

mode, as the device is configured to save power in short periods between single bytes of

the message.

AN4635 Datasheet(PDF) 14 Page - STMicroelectronics