STCF04 datasheet(26/43 Pages) STMICROELECTRONICS

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Description of the internal registers

STCF04

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Doc ID 022927 Rev 3

9.4

Status (STAT_REG) 03(hex)

F_RUN: this bit is kept HIGH by the STCF04 during Flash mode. By checking this bit, the

microprocessor can verify if the Flash mode is running or has been terminated by the time

counter.

FL_R: (FLASH ready) this bit is set to 0 if the SuperCap voltage is not high enough to make

a flash.

NTC_W: this bit is set HIGH by the STCF04 and the ATN pin is pulled down, when the

voltage seen on the pin RX exceeds VREF4 = 0.56 V. This threshold corresponds to a

warning temperature value at the LED measured by the NTC. The device is still operating,

but a warning is sent to the microprocessor. This bit stays high until the temperature goes

below the threshold.

NTC_H: this bit is set HIGH by the STCF04 and the ATN pin is pulled down, when the

voltage seen on the pin RX exceeds VREF5 = 1.2 V. This threshold corresponds to an excess

temperature value at the LED measured by the NTC. The device is put into Idle mode to

avoid damaging the LED. This bit is reset by the STCF04 following a read operation of the

STAT_REG.

OT_F: this bit is set HIGH by the STCF04 and the ATN pin is pulled down, when the chip

overtemperature protection (~140 °C) has put the device into Idle mode. This bit is reset by

the STCF04 following a read operation of the STAT_REG.

FL_OVR: this bit is set HIGH, if the flash operation is terminated by the light sensor.

LTH: this bit is set HIGH when the local temperature protection for the SuperCap charging

circuit is activated.

Table 16.

Auxiliary LED timing table

AUXT (hex)

2345

6789

AUX LED

time [s]

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.1

1.2

1.3

1.4

∞

Table 17.

Status register

STAT_REG

(Read mode)

MSB

LSB

SUB ADD=03

N/A

F_RUN

FL_R

NTC_W

NTC_H

OT_F

FL_OVR

LTH

Power-ON, Shutdown

mode RESET value

000

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