Power consumption comparison

AN4635

22/34

DocID027290 Rev 1

6.7

Different peripheral clock settings

DMA based communication was measured on three different APB clock divider settings, as

shown in Figure 8, where the black line represents current consumption with no divider, the

purple and green lines with divider set to 4 and to 8, respectively. Test with divider set to 16

is not included in the picture, as it would be difficult to distinguish it from the green one (and

the power savings are even more marginal in comparison).

Table 9. Configurations - AHB divider

Curve in Figure 7

Black

Green

Red

Idle mode between

transmissions

Stop

JTAG interface

OFF

Current average

over phases 2, 3 and 4

16.69 µA

9.75 µA

14.06 µA

Clock

1 MHz MSI

250 kHz MSI

1 MHz MSI

Voltage regulator

Range 3

AHB/APB ratio

1/1

4/1

ULP/FWU

+/+

Baud rate

9600

SW used

Blocking operation (Com Polling) with RXSLEEP and TXSLEEP defined