AN4102

Application description

Doc ID 023129 Rev 1

7/16

Once recorded, this value does not need to be refreshed and is kept in the non-volatile

memory for future use. It is recommended to perform this operation when you start your

evaluation in order to obtain the best precision.

Figure 4.

Bias current sequence

1.6

Low-power modes

This section describes the low-power modes used in this application example.

1.6.1

Low-power run mode (without LCD)

In this mode, the CPU and some of the peripherals are running. The LCD and the RTC clock

are disabled to save power and the GPIOs are placed in an output push-pull configuration to

limit consumption. During low-power run mode, the code is executed from the RAM and the

CPU is clocked by the LSI oscillator. The Flash and data EEPROM are stopped and the

voltage regulator is configured in ultra-low power mode. The microcontroller can be woken

up from this power-saving mode by an external event generated by a GPIO.

Set JP2 «Idd»

OFF

Press USER2 and

maintain it

pressed

Power supply

STM8AL board

LD4 ON

Release USER2

button

STM8AL

board is not

powered yet

END

START

«**BIAS**»

displayed on LCD

Measuring,

displaying and

recording Ibias

current

Remove STM8AL

board power

supply

Set JP2 «Idd»

ON

This operation is done

until the user

removes the power

supply by disconnecting

the USB cable