L9679P datasheet(158/272 Pages) STMICROELECTRONICS

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Deployment drivers

L9679P

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DocID029275 Rev 1

8.1.3

Deployment control flow

Deployment control logic requires the following conditions to be true to successfully operate

a deployment:



POR = 0



SSM to be either in Safing State or Arming State



a valid arming condition processed by safing logic or ARMx signals to be set

(depending on selection of internal or external safing engine)



channel-specific deploy command request bits to be set via SPI in the Deploy

command Register (DEPCOM)



a global deployment state has to be active, as described in the following figure.

Figure 31. Global SPI deployment enable state diagram

In case a multiple deployment request would be needed, i.e. deploying the same channel in

sequence, a toggle on DEP_DISABLED has to be performed and a new DEPCOM

command on the same channel has to be sent.

The SPI DEPCOM command is ignored if the device is in the DEP_DISABLED state and the

deploy command is not set. While in DEP_ENABLED state, the following functionalities that

could be active are forced to their reset state:



All squib and DC sensor diagnostic current or voltage sources



All squib, DC sensor and ADC diagnostic MUX settings, state machine, etc.

The SPI_LOCK and SPI_UNLOCK signals are available in the SPIDEPEN command:

High-side and Low-side enablers (ARMx) are assigned to the desired channels by means of

the programmable loop matrix. Deploy commands in the Deploy Command Register

(DEPCOM) are channel specific.

Deployment requires a valid arming condition from safing logic or ARMx signals to be set

any time before, during or after the specific sequence of deploy commands is received. It is

feasible for a deploy command to be received without a valid arming condition from safing

logic or the ARMx being set. In this case, the deploy command will be terminated according

to the Deploy command expiration timer. Likewise, a valid arming condition signal can be

set without receiving a Deploy Command. In this case, the enabling signals will remain

L9679P Datenblatt(PDF) 158 Page - STMicroelectronics