L9654 datasheet(25/59 Pages) STMICROELECTRONICS

25 / 59 page

DocID14218 Rev 3

25/59

L9654

Functional description

messages and their responses are summarized in the below table. The rest of the channels

shall resume their operations and respond to specific SPI commands.

During a deployment, the device ignores arming commands. and does not refresh or

terminate the pulse stretch timer when it receives an arming command.

Table 12. SPI transmission during a deployment

SPI MOSI

SPI MISO(1)

1. SPI MISO sent in the next SPI transmission.

SPI fault response

MOSI register mode message shall be ignored

Command mode

Execute for channels not in deployment; no effect

to deploying channel

Diagnostic mode

SPI fault response

MOSI diagnostic mode message shall be ignored

Monitor mode

Status response

Execute for all channels

4.10

DEPEN

DEPEN is a deployment enable input, which is an active high input. When this pin is

asserted, L9654 is able to turn on its high and low-side drivers upon receiving a valid

deployment command or a MOS diagnostic request. DEPEN cannot interrupt a deployment

that is already in-progress.

When DEPEN is negated, it inhibits the low-side and the high-side MOS from turning on

(inhibit the deployment). When a MOS diagnostic is requested, the device executes the

diagnostic even without the ability to turn on the MOS. It sets the proper SPI threshold bits.

SPI remains functional while this pin is pulled low.

When DEPEN is negated, SPI deploy command is prevented from initiating the pulse

stretch timer. Regardless of DEPEN, “SPI deploy command” status bits reports the state of

“SPI deploy command” bits sent in the previous SPI transfer. This feature is required so that

the processor can diagnose SPI deploy command bits with DEPEN negated.

Regardless of DEPEN, arming signal is able to initiate the pulse stretch timer. This feature is

used for the processor to diagnose the arming signal.

When the pulse stretch timer has been running, changes in the state of DEPEN do not affect

the pulse stretch timer. The pulse stretch timer is not affected regardless of the pulse stretch

timer being started by an arming signal or an SPI deploy command.

A de-glitch timer is provided to DEPEN pin. The timer protects this pin against spurious

glitches. The device neglects DEPEN signal if it is asserted/negated for shorter than

tGLITCH.

Notes

L9654 Datasheet(PDF) 25 Page - STMicroelectronics

L9654 Datasheet(HTML) 25 Page - STMicroelectronics

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59

Datasheet Download

Link URL