L9800 datasheet(14/55 Pages) STMICROELECTRONICS

14 / 55 page

The default operation mode to switch on the loads is active mode. If the device is not in active mode and a

request to switch on one or more outputs occurs (via SPI or via input pins) it switches into active or limp-home

mode, according to IDLE pin status. Due to the time needed for such transitions, output turn-on time tON is

extended due to the mode transition latency.

The state diagram is described in the Figure 4. It is valid if the digital NPOR is ‘1’. In the case of POR=’0’

transitions from active to idle and from limp-home to sleep do not ensure switch off behavior with functional

timings, but the switch off times extended to tOFF_POR. An NPOR condition is registered in clear on the read

NPOR bit of the STA_1 register.

In the case of condition IDLE=’0’ and INn=’0’ (corresponding to the transition from active to sleep) the device

moves in sleep mode. The transition ACTIVE2SLEEP is not effective if at least one channel is on (only when SPI

and PWM drive the channels). In order to turn off a channel before the transition from active to sleep, the bit

CFG_0. ACTIVE TO SLEEP DIS SWR shall be set to 1.

Figure 4. State diagram

Limp-home mode

Sleep mode

Active mode

Idle mode

Idle="low"

INn="low

Idle="high"

Idle="low",

Idle="low"

Idle="low", INn="high"

Idle="low"

Idle="high"

CFG_1.ACT=0 & PWM_SPI.OUTn=0 &

(PWM_MAPn=0 or

selected internal PWM=0)

&(MAP_INn.OUTn=0 or INn="low"

)

CFG_1.ACT=1 or

PWM_SPI.OUTn=1 or

(PWM_MAPn=1 &

selected internal PWM=1)

or (MAP_INn.OUTn=1 & INn="high")

Active

INn="high"

The Table 10 shows the correlation between device operation modes, VBATT and VDDIO supply voltages, and

the state of the most important functions (channels operativity, SPI communication, and SPI registers).

L9800

Power supply

DS14041 - Rev 2

page 14/55

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