L99H92 datasheet(61/77 Pages) STMICROELECTRONICS

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Table 62. Watchdog trigger/disable register WDGTRDIS (0x0A) MSB

Bit 15

Bit 14

Bit 13

Bit 12

Bit 11

Bit 10

Bit 9

Bit 8

WDGTRDIS[14] WDGTRDIS[13] WDGTRDIS[12]

WDGTRDIS[11]

WDGTRDIS[10]

WDGTRDIS[9]

WDGTRDIS[8] WDGTRDIS[7]

Watchdog trigger/disable bits

Bit

Name

Description

WDGTRDIS[14]

The register can be used either to disable the watchdog or to trigger the watchdog

Watchdog trigger/disable bits. In order to trigger the watchdog all the register bits must toggle

within the watchdog open window. The first trigger word must be 5555h, this value puts an end to

the watchdog long open window and turn the watchdog in window mode. The following trigger

values must be 2AAAh, 5555h, 2AAAh and so on.

To disable the watchdog, the microcontroller has to send a specific key, consisting in two

consecutive words, corresponding to two consecutive valid SPI transfers (without any other SPI

transfer between the two of them), during any watchdog long open window. The keys to disable

the watchdog are 2F6Bh (first key word) and 1097h (second key word). The two words key has to

be sent in the right order, otherwise the watchdog will not be disabled, and a watchdog fault will

be generated.

First trigger bits value (5555h): 101010101010101b

Second trigger bits value (2AAAh): 010101010101010b

First part of the disable key (2F6Bh): 010111101101011b

Second part of the disable key (1097h): 001000010010111b

WDGTRDIS[13]

WDGTRDIS[12]

WDGTRDIS[11]

WDGTRDIS[10]

WDGTRDIS[9]

WDGTRDIS[8]

WDGTRDIS[7]

Table 63. Watchdog trigger/disable register WDGTRDIS (0x0A) LSB

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

WDGTRDIS[6] WDGTRDIS[5] WDGTRDIS[4]

WDGTRDIS[3]

WDGTRDIS[2]

WDGTRDIS[1]

WDGTRDIS[0]

Watchdog trigger/disable bits

Parity bit

Bit

Name

Description

WDGTRDIS[6] The register can be used either to disable the watchdog or to trigger the watchdog

Watchdog trigger/disable bits. In order to trigger the watchdog all the register bits must toggle within the

watchdog open window. The first trigger word must be 5555h, this value puts an end to the watchdog turn

open window and turn the watchdog in window mode. The following trigger values must be 2AAAh, 5555h,

2AAAh and so on.

In order to disable the watchdog, the microcontroller has to send a specific key, consisting in two consecutive

words, corresponding to two consecutive valid SPI transfers (without any other SPI transfer between the two

of them), during any watchdog long open window. The keys to disable the watchdog are 2F6Bh (first key

word) and 1097h (second key word). The two words key has to be sent in the right order, otherwise the

watchdog will not be disabled and a watchdog fault will be generated.

First trigger bits value (5555h): 101010101010101b

Second trigger bits value (2AAAh): 010101010101010b

First part of the disable key (2F6Bh): 010111101101011b

Second part of the disable key (1097h): 001000010010111b

WDGTRDIS[5]

WDGTRDIS[4]

WDGTRDIS[3]

WDGTRDIS[2]

WDGTRDIS[1]

WDGTRDIS[0]

Parity bit

Table 64. Watchdog trigger/disable register WDGTRDIS (0x0A) MSB

Bit 15

Bit 14

Bit 13

Bit 12

Bit 11

Bit 10

Bit 9

Bit 8

0 (R)

RES

L99H92

Control registers

DS14069 - Rev 4

page 61/77

L99H92 Datasheet(PDF) 61 Page - STMicroelectronics

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