L9966 datasheet(19/122 Pages) STMICROELECTRONICS

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Figure 10. Combination of two consecutive WAKE SOURCES determines a WAKE EVENT

GADG0501180956PS

Once the WAKE EVENT is recognized, the IC enters WAKE mode.

If at the end of the sum of the 2 timeouts (PB+PT), the state is still different from the one recorded in

SLEEP_CONFIG register, the DIG_IN_STAT_LTC will be written with the XOR of all and only the IO configured as

WAKE SOURCES (WAK_MSK register) which changed their value during polling: ‘1’ means the status changed,

‘0’ means no change. Then the IC enters in WAKE mode, the WAKE pin is asserted high and the WAK_UP_FLG

in GEN_STATUS is set.

Figure 11. SLEEP-POLLING operation example

GADG0501181036PS

Figure 11 shows a SLEEP mode scenario. In this case, CH5 and CH14 are configured as WAKE SOURCES with

SEL = "001" and "100" respectively. When the RST is driven low, the device enters SLEEP mode.

•

During the first sleep period, CH1 changes its value from ‘1’ to ‘0’. Nonetheless, after polling blanking time,

only CH5 and CH14 are checked against their original value, then device re-enters immediately sleep mode.

•

At second sleep-polling cycle, CH5 changes its value from ‘1’ to ‘0’. After the Polling timeout PT has

expired, device enters WAKE mode. Only after RST is driven high again, the device re-enters INIT mode for

diagnostic checks and finally NORMAL mode.

It is forbidden to use UTh_ratio to detect an eventual WAKE EVENT.

5.9

SLEEP mode

To enter SLEEP mode, the following steps must be done:

Select which channel should be polled in SLEEP mode to detect the wake-up event. This is done by setting

the corresponding bit in WAK_MSK register. Only IO properly configured through SEL bit can be defined

as WAKE UP sources; the IO with SEL bit not properly configured for the function is ignored in WAK_MSK

L9966

SLEEP mode

DS12459 - Rev 10

page 19/122

L9966 датащи(PDF) 19 Page - STMicroelectronics