L9680 datasheet(162/277 Pages) STMICROELECTRONICS

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Deployment drivers

L9680

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DocID029257 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. Loop matrix registers are 4, one for each ARMx signals. In

each loop matrix register 12 bits are present to associate independently loops with ARMx

signals. In case external safing is selected LOOP_MATRIX_ARM4 register is don't care

because ARM4 pin is used to arm the low side of all loops without association 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

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