L99DZ120 datasheet(62/162 Pages) STMICROELECTRONICS

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L99DZ120

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DocID029145 Rev 4

4.3.2

Flash mode

To program the system microcontroller via LIN bus signals, the devices can be operated in

LIN Flash mode. The watchdog is disabled in this mode.

The Flash mode is entered by applying an external voltage at the pin:



VLIN_FLASH ≥ VFlashH (LIN Flash mode)

In LIN Flash mode the maximum bitrate is increased to 100 kbit/s automatically

(LIN_HS_EN = 1).

A transition from Flash mode to V1_standby or Vbat_standby mode is not possible.

At exit from Flash modes (VLIN_FLASH < VFlashL) no NReset pulse is generated. The

watchdog starts with a Long Open Window (tLW).

4.3.3

SW-debug mode

To allow software debugging, the watchdog can be deactivated by applying an external

voltage to the DEBUG input pin (Vdebug > VdiH).

In Debug mode, all device functionality and Operating modes are available. The watchdog

is deactivated. At Exit from Debug mode (Vdebug < VdiL) the watchdog starts with a Long

Open Window.

Note:

The device includes a test mode. This mode is activated by a dedicated sequence which

includes a high voltage at the Debug Pin. The Debug Pin must be kept at nominal voltage

levels in order to avoid accidental activation of the test mode.

4.3.4

V1_standby mode

The transition from Active mode to V1_standby mode is controlled by SPI.

To supply the micro controller in a low power mode, the V1 voltage regulator remains active.

After the V1_standby command (CSN low to high transition), the device enters V1_standby

mode immediately and the watchdog starts a Long Open Window (tLW). The watchdog is

deactivated as soon as the V1 load current drops below the ICMP threshold (IV1< Icmp_fal).

The V1 load current monitoring can be deactivated by setting ICMP = 1. In this configuration

the watchdog will be deactivated upon transition into V1_standby mode without monitoring

the V1 load current.

Writing ICMP (CR 34) = 1 is only possible with the first SPI command after setting

ICMP_CONFIG_EN (Config Reg) = 1.

The ICMP_CONFIG_EN bit is reset to 0 automatically with the next SPI command.

Power outputs (except OUT_HS & OUT15) are switched off in V1_standby mode. OUT_HS

& OUT15 remain in the configuration programmed prior to the standby command in order to

enable (cyclic) supply of external contacts. The timer signal (Timer1 or Timer2) can be

mirrored to the NINT output pin during V1_standby mode.

LIN transmitter (TxDL) is off.

L99DZ120 Datasheet(PDF) 62 Page - STMicroelectronics

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