33972 View Datasheet(PDF) - Freescale Semiconductor

Part Name

Description

Manufacturer

33972

Multiple Switch Detection Interface with Suppressed Wake-up

Freescale Semiconductor 

TIMING DIAGRAMS

ELECTRICAL CHARACTERISTICS

TIMING DIAGRAMS

CS

SCLK

SI

0.2 VDD

t LEAD

0.7 VDD

0.2 VDD

tSI(SU) tSI(HOLD)

0.7 VDD

0.2 VDD

MSB IN

SO

tSO(EN)

0.7 VDD

0.2 VDD

MSB OUT

t VALID

Figure 4. SPI Timing Characteristics

t LAG

LSB OUT

tSO(DIS)

VPWR

VDD

WAKE

INT

CS

Wake-up From Interrupt

Timer Expire

SGn

Power-up

Normal Mode

Tri-state

Command

(Disable

Tri-state)

.

INT

Sleep

Command

Sleep Mode

Normal

Mode

Sleep Command Sleep Mode

Figure 5. Sleep Mode to Normal Mode Operation

Switch state change with

CS LOW generates INT

Wake-up From

Closed Switch

Normal

Mode

Sleep Command

Switch state change with

CS LOW generates INT

Latch switch status

CS

on falling edge of CS

SGn

SGn Bit in SPI Word

1

Switch

Status

Command

Rising edge of CS does not

clear INT because state change

occurred while CS was LOW

0

Switch

Status

Command

0

Switch

Status

Command

Switch closed “1”

1

Switch

Status

Command

Figure 6. Normal Mode Interrupt Operation

1

Switch

Status

Command

Switch open “0”

0

Switch

Status

Command

Analog Integrated Circuit Device Data

Freescale Semiconductor

33972

9

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