SPSB0813 datasheet(17/135 Pages) STMICROELECTRONICS

17 / 135 page

•

LIN_WU_EN = 1

•

WU1_EN = 1

•

WU2_EN = 1

For SPSB081C devices (without LIN), at least one of these WU sources has to be kept (CAN, WU1 or WU2).

All wake-up sources are configured to default values in case of such invalid setting. The SPI error bit (SPIE) in the

global status register is set.

3.4.1

Wake-up inputs

The WU1 and WU2 inputs can be configured as wake-up sources. Each wake-up input is sensitive to any

level transition (positive and negative edge) and can be configured for static or cyclic monitoring of the input

voltage level by suitable setting of CR1 [8..11] bits (WUx_FILT_0 and WUx_FILT_1) which allows to choose the

monitoring among static, cyclic with timer 1 or cyclic with timer 2. When the configuration of a timer is changed,

the timer is automatically restarted using the new configuration.

For static contact monitoring, a filter time of tWU_stat is implemented. The filter is started when the input voltage

passes the specified threshold Vwuthp. Wake-up status bit (WUx_STATE bit in SR5 [18..19]) is set only if this

threshold is passed for more than tWU_stat.

Cyclic contact monitoring, conceived to reduce the quiescent current of the device, allows instead periodical (not

threshold dependent) activation of the wake-up input to read the status of the external contact. The periodical

activation is driven by timer 1 or timer 2 whose settings (on-time and period) can be configured through CR2

[8..13] and [16..21] bits (Tx_PER_y and Tx_ON_y bit). The input signal is filtered with a filter time of tWU_cyc after

a delay (80% of the configured timer on-time). A wake-up will be processed if the status has changed versus

the previous cycle, therefore wake-up status bit (WUx_STATE bit in SR5 [18..19]) is set only if status during

consecutive on-time is different, after the configured delay and tWU_cyc.

The buffered outputs OUT1, OUT2, OUT3, and OUT4 can be used to supply the external contacts with the timer

setting according to the cyclic monitoring of the wake-up input.

Figure 8. Static monitoring: wake-up occurs if threshold is greater than the filter time

0.55 * VS

t < 64µs

No Wake Up

Event

tt =

= 6644µµss

tt =

= 6644µµss

U IInnppuutt

Sttaattuuss B

Biitt

Internal Wake-up requests identified



Start to oscillator and precise comparator

S S

200µA

(typ)

7µA

(typ)

Reduced Quiescent Current!

GAPG1009151518CFT

SPSB081

Wake-up from standby modes

DS14048 - Rev 1

page 17/135

SPSB0813 データシート(PDF) 17 Page - STMicroelectronics

SPSB0813 データシート(HTML) 17 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 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

データシートダウンロード