L9654 datasheet(24/59 Pages) STMICROELECTRONICS

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Functional description

L9654

24/59

DocID14218 Rev 3

A deployment-en/disable command does not affect the timer operation started by arming

signal.

When an arming-enable command is sent through SPI, the pulse stretcher is initiated

immediately following the falling edge of CS_A. When another arming-enable command is

sent before the timer for the previous command expired, the timer is refreshed. Sending an

arming disable command terminate the pulse stretch timer operation. ONLY a timer

operation started by an arming-enable command can be terminated. An arming-en/disable

command does not affect the timer operation started by a valid deployment command.

Figure 12. Deployment flow chart

1. MOSI Register Mode: ignored. Next MISO: SPI fault response

MOSI Command Mode: execute for channels NOT in deployment, NO effect to deploying channel. Next MISO: Command

mode response

MOSI Diagnostic Mode: ignored. Next MISO: SPI fault response

MOSI Monitor Mode: execute for all channels. Next MISO: Status response

During the deployment, L9654 turns on the respective high (SQH) and low-side (SQL)

drivers for tDEPLOY. Once deployment is initiated it cannot be terminated. When a channel is

in deployment, this particular channel shall only act upon certain SPI messages. These SPI

L9654 Datasheet(PDF) 24 Page - STMicroelectronics