AN3223

Operation modes

Doc ID 17553 Rev 2

11/29

5

Operation modes

5.1

Shutdown mode

Shutdown mode is entered after the Power-ON reset. This mode is mainly used to decrease

action which can be performed in Shutdown mode is to access the COMMAND and

FEATURE registers. Entering Shutdown mode by writing to the COMMAND register aborts

any running operation and clears the values of the FLASH, AUX_LED, STATUS, and

TORCH registers. The COMMAND and FEATURE register values are not affected by

entering Shutdown mode, but an attempt to read their value always gives 0 when the bit

PWR_ON = 0.

The following data must be written to the COMMAND register to enter Shutdown mode.

5.2

Monitoring mode

The super-capacitor voltage is monitored by a comparator in this mode. The comparator is

the only analog circuit which is enabled and that is why the consumption of the STCF04 is

minimized in this mode. Information about the super-capacitor voltage is given by the logic

register.

Monitoring mode can be entered from Shutdown mode by setting the MONTR bit in the

COMMAND register to 1.

Table 3.

COMMAND register data for entering Shutdown mode

CMD_REG

PWR_ON FLASH_ON

TCH_ON

NTC_ON

TCHV_H

CHRG

MONTR

N/A

0

x

xxxx

0

0

MSB

LSB

Table 4.

VDC_1

VDC_0

00

4.5 V

01

5.0 V

10

5.5 V

Table 5.

COMMAND register data for entering Monitoring mode

CMD_REG

PWR_ON FLASH_ON

TCH_ON

NTC_ON

TCHV_H

CHRG

MONTR

N/A

0

x

xxxx

1

0

MSB

LSB