ST7DALIF2 datasheet(44/171 Pages) STMICROELECTRONICS

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Supply, reset and clock management

ST7DALIF2

44/171

9.7.4

System integrity (SI) control/status register (SICSR)

Read/Write

Reset Value: 0000 0xx0 (0xh)

Bit 7:5 = Reserved, must be kept cleared.

Bit 4 = WDGRF Watchdog reset flag

This bit indicates that the last Reset was generated by the Watchdog peripheral. It is set by

hardware (watchdog reset) and cleared by software (writing zero) or an LVD Reset (to

ensure a stable cleared state of the WDGRF flag when CPU starts).

Combined with the LVDRF flag information, the flag description is given by the following

table.

Bit 3 = LOCKED PLL Locked Flag

This bit is set and cleared by hardware. It is set automatically when the PLL reaches its

operating frequency.

0: PLL not locked

1: PLL locked

Bit 2 = LVDRF LVD reset flag

This bit indicates that the last Reset was generated by the LVD block. It is set by hardware

(LVD reset) and cleared by software (by reading). When the LVD is disabled by OPTION

BYTE, the LVDRF bit value is undefined.

Bit 1 = AVDF Voltage Detector flag

This read-only bit is set and cleared by hardware. If the AVDIE bit is set, an interrupt request

is generated when the AVDF bit is set. Refer to Figure 18 and to Monitoring the VDD main

supply on page 42 for additional details.

0: VDD over AVD threshold

1: VDD under AVD threshold

Bit 0 = AVDIE Voltage Detector interrupt enable

This bit is set and cleared by software. It enables an interrupt to be generated when the

AVDF flag is set. The pending interrupt information is automatically cleared when software

enters the AVD interrupt routine.

0: AVD interrupt disabled

1: AVD interrupt enabled

Note:

The LVDRF flag is not cleared when another RESET type occurs (external or watchdog), the

LVDRF flag remains set to keep trace of the original failure.

In this case, a watchdog reset can be detected by software while an external reset can not.

WDGRF

LOCKED

LVDRF

AVDF

AVDIE

Table 14.

Reset flags

RESET sources

LVDRF

WDGRF

External RESET pin

Watchdog

LVD

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