LDLL16ENTR datasheet(11/102 Pages) STMICROELECTRONICS

11 / 102 page

Functional description

4.1

Operating modes

The LDLL16EN features different operating modes. The related device states are reported in Figure 8 and well

detailed in the following sub-chapters.

There are 2 bits for safe transition between different modes: BUSMODE and GOSTBY bits (see the

Section 6: FTP and RAM memory mapping) configuration is used to set, leave and check device normal/bus

operating mode.

A dedicated pattern through the CAN FD light compatible interface is used to wake up and to send to sleep the

device. On top of that, the device can be opportunely woken up or sent to sleep also through the DIN pin and

(BUSMODE, GOSTBY) bits respectively.

As the device potentially controls safety critical functions such as brake and turn indicators, built-in features are

integrated to support a high level of functional safety on the application level. The LDLL16EN features a

programmable timeout watchdog by WD_CONF (2 bits, see the Section 6: FTP and RAM memory mapping), a

monitoring of the watchdog counter by WD_STATUS (2 bits, see the Section 6: FTP and RAM memory mapping),

a fail-safe, and a direct input mode.

To keep the device in normal/bus mode, a watchdog trigger bit (WD_TRIG<0>, see the Section 6: FTP and RAM

memory mapping) is cyclically toggled within the programmable watchdog timeout period. In case of watchdog

failure, the WD_FAIL bit (see the Section 6: FTP and RAM memory mapping) is set and the device leaves

normal/bus mode operation to enter fail-safe mode.

Figure 8. Device state diagram

Fail Safe/

Stand Alone

Device operates according to FTP setting

and DIN* CAN Interface Wait for communication

from Commander

Note: ctrl register can be written but are not active

*Channel activation is delayed by tPOR_DELAY when

entering after a Power On Reset

Note:

Partial networking feature is not supported by the device. Mixed state on the bus has to be avoided. In case

devices are sent to initialization/standby mode NOT through a broadcast "send to sleep" command, the first

UNICAST response frame of the device after wakeup has to be ignored.

LDLL16EN

Functional description

DS14111 - Rev 5

page 11/102

LDLL16ENTR Datasheet(PDF) 11 Page - STMicroelectronics