ST7LITE20 datasheet(33/131 Pages) STMICROELECTRONICS

33 / 131 page

ST7LITE2

33/131

SYSTEM INTEGRITY MANAGEMENT (Cont’d)

7.6.4 Register Description

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 generat-

ed by the Watchdog peripheral. It is set by hard-

ware (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 au-

tomatically when the PLL reaches its operating fre-

quency.

0: PLL not locked

1: PLL locked

Bit 2 = LVDRF

LVD reset flag

This bit indicates that the last Reset was generat-

ed by the LVD block. It is set by hardware (LVD re-

set) 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 gen-

erated when the AVDF bit is set. Refer to Figure

19 and to Section 7.6.2.1 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 automati-

cally cleared when software enters the AVD inter-

rupt routine.

0: AVD interrupt disabled

1: AVD interrupt enabled

Application notes

The LVDRF flag is not cleared when another RE-

SET type occurs (external or watchdog), the

LVDRF flag remains set to keep trace of the origi-

nal failure.

In this case, a watchdog reset can be detected by

software while an external reset can not.

WDG

LOCKED LVDRF AVDF AVDIE

RESET Sources

LVDRF

WDGRF

External RESET pin

Watchdog

LVD

ST7LITE20 数据表(PDF) 33 Page - STMicroelectronics

ST7LITE20 数据表(HTML) 33 Page - STMicroelectronics

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

数据表下载