Power consumption and wakeup time measurements and results

AN2857

22/31

Doc ID 15241 Rev 3

Observations

●

●

When the code is executed from RAM, the code execution time is longer than when the

code is executed from Flash.

●

Consumption does not depend on the supply voltage when an internal clock is used

(HSI or LSI). This is because the internal oscillators are supplied by the internal 1.8 V.

●

The effect of memory placement is not shown in Table 5 and Table 6. However, if the

size of a loop is smaller than the size of a memory block, placing the loop in the same

memory block can reduce power consumption. In this case, only one block of memory

is active.

●

The effect of the instruction executed is not shown in Table 5 and Table 6. However,

consumption in run mode depends on the executed instruction and the operands of this

instruction. Examples of instructions which do not consume at a high rate include:

INC A and NOP. Examples of instructions which consume at a high rate include LD

(from Flash) and ADD A, #$01.

●

Consumption of the crystal oscillator is about:

–

5 V: 0.6 mA

–

3.3 V: 0.3 mA

5.1.3

Power consumption results in wait mode

Observations:

●

●

Consumption does not depend on the supply voltage when an internal clock is used

(HSI or LSI). This is because the internal oscillators are supplied by the internal 1.8 V.

●

Consumption of the crystal oscillator is about:

–

5 V: 0.6 mA

–

3.3 V: 0.3 mA

Table 7.

Power consumption results in wait mode

Symbol

Parameter

Condition

Unit

Supply current in

wait mode

HSE crystal

2.0

2.4

mA

HSE external clock

1.8

1.8

HSE crystal

1.6

2.0

HSE external clock

1.4

1.4

HSI

1.2

1.2

HSI

1.0

1.0

LSI

0.50

0.50