Data Sheet

Freescale Semiconductor
Advance Information
Document Number: MC33978
Rev. 5.0, 8/2015
22 Channel Multiple Switch Detection
Interface with Programmable Wetting
Current
33978
34978
MULTIPLE SWITCH DETECTION INTERFACE
The 33978 is designed to detect the closing and opening of up to 22 switch
contacts. The switch status, either open or closed, is transferred to the
microprocessor unit (MCU) through a serial peripheral interface (SPI). This
SMARTMOS device also features a 24-to-1 analog multiplexer for reading the
input channels as analog inputs. The analog selected input signal is buffered
and provided on the AMUX output pin for the MCU to read.
Independent programmable wetting currents are available as needed for the
application. A battery and temperature monitor are included in the IC and
available via the AMUX pin.
The 33978 device has two modes of operation, Normal and Low Power Mode
(LPM). Normal mode allows programming of the device and supplies switch
contacts with pull-up or pull-down current as it monitors the change of state on
the switches. The LPM provides low quiescent current, which makes the 33978
ideal for automotive and industrial products requiring low sleep-state currents.
Features
• Fully functional operation 4.5 V ≤ VBATP ≤ 36 V
• Full parametric operation 6 V ≤ VBATP ≤ 28 V
• Operating switch input voltage range from -1 V to 36 V
• Eight programmable inputs (switches to battery or ground)
• 14 switch-to-ground inputs
• Selectable wetting current (2, 6, 8, 10, 12, 14, 16, or 20 mA)
• Interfaces directly to an MCU using 3.3 V / 5.0 V SPI protocol
• Selectable wake-up on change of state
• Typical standby current IBATP = 30 A and IDDQ = 10 A
• Active interrupt (INT_B) on change-of-switch state
• Integrated battery and temperature sensing
EK SUFFIX (PB-FREE)
98ASA10556D
32-PIN SOICW-EP
Applications
• Automotive
• Heating ventilation and air conditioning (HVAC)
• Lighting
• Central gateway/in-vehicle networking
• Gasoline engine management
• Industrial
• Programmable logic control (PLC)
• Process control, temperature control
• Input-output control (I/O Control)
• Single board computer
• Ethernet switch
VDDQ
Battery
Power
Supply
33978
SG1
Battery
SP0
VBATP
WAKE_B
SP1
SP7
SG0
Power
Supply
MCU
VDDQ
INT_B
INTB
CS_B
MISO
MOSI
SCLK
CSB
MISO
MOSI
SCLK
AMUX
AN0
SG12
SG13
EP
GND
Figure 1. 33978 Simplified Application Diagram
* This document contains certain information on a new product.
Specifications and information herein are subject to change without notice.
© Freescale Semiconductor, Inc., 2014-2015. All rights reserved.
ES SUFFIX (PB-FREE)
98ASA00656D
32-PIN QFN (WF-TYPE)
Table of Contents
1
2
3
Orderable Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Internal Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Pin Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.1 Pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.2 Pin Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4 General Product Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4.1 Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4.2 Thermal Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4.3 Operating Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
4.4 Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
5 General Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
5.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
5.2 Functional Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
6 General IC Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
6.1 Battery Voltage Ranges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
6.2 Power Sequencing Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
7 Functional Block Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
7.1 State Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
7.2 Low-power Mode Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
7.3 Input Functional Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
7.4 Oscillator and Timer Control Functional Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
7.5 Temperature Monitor and Control Functional Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
7.6 WAKE_B Control Functional Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
7.7 INT_B Functional Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
7.8 AMUX Functional Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
7.9 Serial Peripheral Interface (SPI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
7.10 SPI Control Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
8 Typical Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
8.1 Application Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
8.2 Bill of Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
8.3 Abnormal Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
9 Packaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
9.1 Package Mechanical Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
10 Reference Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
11 Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
2
1
Orderable Parts
This section describes the part numbers available to be purchased along with their differences.
Table 1. Orderable Part Variations
Part Number
Temperature (TA)
Package
MC33978EK
MC33978AEK
(1), (2)
-40 °C to 125 °C
MC33978AES
SOICW-EP 32 pins
(1)
QFN (WF-TYPE) 32 pins
MC34978EK
MC34978AEK
MC34978AES
Notes
(1), (2)
-40 °C to 105 °C
SOICW-EP 32 pins
(1)
QFN (WF-TYPE) 32 pins
Notes
1. To order parts in Tape & Reel, add the R2 suffix to the part number.
2. Refer to errata MC33978ER ER01 for details on current conditions present on the MC33978EK and MC34978EK devices only.
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
3
2
Internal Block Diagram
Inputs
VBATP
SG0
Internal 2.5 V
VBATP, VDDQ
Internal 2.5 V/5.0 V
Power On Reset
Bandgap reference
Sleep Power
VBATP
Wetting (2.0 mA to 20 mA)
Sustain (2.0 mA)
Low Power Mode (1.0 mA)
VBATP
VDDQ
GND
EP
SG0
Internal 2.5 V
To SPI
4.0 V
reference
SG1
Oscillator
and
Clock control
SG2
VBATP
VBATP
SG5
Internal 2.5 V
Temperature
Monitor and
Control
Wetting (2.0 mA to 20 mA)
Sustain (2.0 mA)
Low Power Mode (1.0 mA)
VDDQ
125 k
SG5
Internal 2.5 V
To SPI
4.0 V
reference
WAKE_B
WAKE_B control
1/6 Ratio
Internal 2.5 V
VBATP
SGx
VDDQ
125 k
INT_B
Interrupt
control
Wetting (2.0 mA to 20 mA)
Sustain (2.0 mA)
Low Power Mode (1.0 mA)
Internal 2.5 V
SG13
SPI Interface and
Control
To SPI
4.0 V
reference
VDDQ
125 k
CS_B
SCLK
VBATP
SP0-7
VDDQ
Mux control
Wetting (2.0 mA to 20 mA)
Sustain (2.0 mA)
Low Power Mode (1.0 mA)
SP0
MOSI
MISO
24
To SPI
VDDQ
+
-
AMUX
4.0 V
reference
SP1
Wetting (2.0 mA to 20 mA)
Sustain (2.0 mA)
Low Power Mode (2.0 mA)
SP7
Figure 2. 33978 Internal Block Diagram
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
4
3
Pin Connections
3.1
Pinout
Transparent Top View
29
5
28
6
27
7
Exposed Pad
8
EK Suffix
Only
9
10
26
25
24
23
11
22
12
21
13
20
25
24
SP5
SP3
21
SP4
SG0
5
20
SG13
SG1
6
19
SG12
SG2
7
18
SG11
SG3
8
17
SG10
9
10
11
12
13
14
15
16
SG9
22
4
SG8
3
SG7
SP2
WAKE_B
17
26
SP6
VBATP
16
27
SP7
SP1
SG6
18
28
23
1
SG5
19
15
29
2
SP0
SG4
14
30
INT_B
4
32 31
AMUX
30
MISO
3
MISO
VDDQ
AMUX
INT_B
SP7
SP6
SP5
SP4
SG13
SG12
SG11
SG10
SG9
SG8
SG7
WAKE_B
VDDQ
31
GND
32
2
MOSI
1
SCLK
CS_B
GND
MOSI
SCLK
CS_B
SP0
SP1
SP2
SP3
SG0
SG1
SG2
SG3
SG4
SG5
SG6
VBATP
Figure 3. 33978 SOICW-EP and QFN (WF-Type) Pinouts
3.2
Pin Definitions
Table 2. 33978 Pin Definitions
Pin Number Pin Number
Pin Name
SOIC
QFN
Pin Function
Formal Name
Definition
1
29
GND
Ground
Ground
Ground for logic, analog
2
30
MOSI
Input/SPI
SPI Slave In
SPI control data input pin from the MCU
3
31
SCLK
Input/SPI
Serial Clock
SPI control clock input pin
4
32
CS_B
Input/SPI
Chip Select
SPI control chip select input pin
5–8
25 – 28
1-4
21 - 24
SP0 – 3
SP4 – 7
Input
Programmable
Switches 0 – 7
9 – 15,
18 – 24
5 - 11
14 - 20
SG0 – 6,
SG7 –13
Input
Switch-to-Ground
Inputs 0 – 13
16
12
VBATP
Power
Battery Input
17
13
WAKE_B
Input/Output
Wake-up
Open drain wake-up output. Designed to control a power supply
enable pin. Input used to allow a wake-up from an external event.
29
25
INT_B
Input/Output
Interrupt
Open-drain output to MCU. Used to indicate an input switch change
of state. Used as an input to allow wake-up from LPM via an external
INT_B falling event.
30
26
AMUX
Output
31
27
VDDQ
Input
Switch to programmable input pins (SB or SG)
Switch-to-ground input pins
Battery supply input pin. Pin requires external reverse battery
protection
Analog Multiplex Output Analog multiplex output.
Voltage Drain Supply
3.3 V/ 5.0 V supply. Sets SPI communication level for the MISO driver
and I/O level buffer
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
5
Table 2. 33978 Pin Definitions (continued)
Pin Number Pin Number
Pin Name
SOIC
QFN
32
28
Pin Function
Formal Name
Definition
MISO
Output/SPI
SPI Slave Out
Provides digital data from the 33978 to the MCU.
EP
Ground
Exposed Pad
It is recommended that the exposed pad is terminated to GND (pin 1)
and system ground.
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
6
4
General Product Characteristics
4.1
Maximum Ratings
Table 3. Maximum Ratings
All voltages are with respect to ground unless otherwise noted. Exceeding these ratings may cause a malfunction or permanent damage
to the device.
Symbol
Description (Rating)
Min.
Max.
Unit
Notes
ELECTRICAL RATINGS
VBATP
Battery Voltage
-0.3
40
V
VDDQ
Supply Voltage
-0.3
7.0
V
CS_B, MOSI,
MISO, SCLK
SPI Inputs/Outputs
-0.3
7.0
V
SGx, SPx
Switch Input Range
-14
38
V
AMUX
AMUX
-0.3
7.0
V
INT_B
INT_B
-0.3
7.0
V
WAKE_B
-0.3
40
V
WAKE_B
VESD1-2
VESD1-3
VESD3-1
VESD2-1
VESD2-2
ESD Voltage
• Human Body Model (HBM) (VBATP versus GND)
MC33978 and MC34978
MC33978A and MC34978A
• Human Body Model (HBM) (All other pins)
• Machine Model (MM)
• Charge Device Model (CDM) (Corners pins)
• Charge Device Model (CDM) (All other pins)
VESD5-3
VESD5-4
VESD6-1
VESD6-2
• VBATP
• WAKE_B (series resistor 10 k)
• SGx and SPx pins with 100 nF capacitor (100 Ω series R) based on external
protection performance(5)
• SGx and SPx pins with 100 nF capacitor (50  series R)
(3)
V
(4)
±2000
±4000
±2000
±200
±750
±500
Contact Discharge
(6)
V
±8000
±8000
±15000
±8000
Notes
3. ESD testing is performed in accordance AEC Q100, with the Human Body Model (HBM) (CZAP = 100 pF, RZAP = 1500 ), the Machine Model
(MM) (CZAP = 200 pF, RZAP = 0 ), and the Charge Device Model (CDM).
4.
CZAP = 330 pF, RZAP = 2.0 kPowered and unpowered) / CZAP = 150 pF, RZAP = 330 Unpowered)
5.
6.
±15000V capability in powered condition, ±8000V in all other conditions.
External component requirements at system level: 
Cbulk = 100uF aluminum electrolytic capacitor
Cbypass=100nF ±37% ceramic capacitor 
Reverse blocking diode from Battery to VBATP (0.6 V < VF < 1 V). See Figure 23, Typical Application Diagram.
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
7
4.2
Thermal Characteristics
Table 4. Thermal Ratings
All voltages are with respect to ground unless otherwise noted. Exceeding these ratings may cause a malfunction or permanent damage
to the device.
Symbol
Description (Rating)
Min.
Max.
Unit
Operating Temperature
• Ambient
• Junction
-40
-40
125
150
°C
TSTG
Storage Temperature
-65
150
°C
TPPRT
Peak Package Reflow Temperature During Reflow
–
–
°C
Notes
THERMAL RATINGS
TA
TJ
THERMAL RESISTANCE
RJA
Junction-to-Ambient, Natural Convection, Single-Layer Board
• 32 SOIC-EP
• 32 QFN
79
94
°C/W
(7) (8)
RJB
Junction-to-Board
• 32 SOIC-EP
• 32 QFN
9.0
12
°C/W
(9)
RJC
Junction-to-Case (Bottom)
• 32 SOIC-EP
• 32 QFN
3.0
2.0
°C/W
(10)
Junction-to-Package (Top), Natural convection
• 32 SOIC-EP
• 32 QFN
11
2.0
°C/W
(11)
JT
,
PACKAGE DISSIPATION RATINGS
TSD
Thermal Shutdown
• 32 SOIC-EP
• 32 QFN
155
185
°C
TSDH
Thermal Shutdown Hysteresis
• 32 SOIC-EP
• 32 QFN
3.0
15
°C
Notes
7. Junction temperature is a function of die size, on-chip power dissipation, package thermal resistance, mounting site (board) temperature, ambient
temperature, air flow, power dissipation of other components on the board, and board thermal resistance.
8. Per JEDEC JESD51-2 with natural convection for horizontally oriented board. Board meets JESD51-9 specification for 1s or 2s2p board,
respectively.
9. Thermal resistance between the die and the printed circuit board per JEDEC JESD51-8. Board temperature is measured on the top surface of the
board near the package.
10. Thermal resistance between the die and the solder pad on the bottom of the package based on simulation without any interface resistance.
11. Thermal characterization parameter indicating the temperature difference between package top and the junction temperature per JEDEC JESD512. When Greek letters are not available, the thermal characterization parameter is written as Psi-JT.
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
8
4.3
Operating Conditions
This section describes the operating conditions of the device. Conditions apply to all the following data, unless otherwise noted.
Table 5. Operating Conditions
All voltages are with respect to ground unless otherwise noted. Exceeding these ratings may cause a malfunction or permanent damage
to the device.
Symbol
Ratings
Min.
Max.
Unit
VBATP
Battery Voltage
4.5
36
V
VDDQ
Supply Voltage
3.0
5.25
V
CS_B, MOSI,
MISO, SCLK
SPI Inputs / Outputs
3.0
5.25
V
SGx, SPx
Switch Input Range
-1.0
36
V
AMUX, INT_B
0.0
5.25
V
WAKE_B
0.0
36
V
AMUX, INT_B
WAKE_B
4.4
Notes
Electrical Characteristics
4.4.1
Static Electrical Characteristics
Table 6. Static Electrical Characteristics
TA = - 40 °C to +125 °C, VDDQ = 3.1 V to 5.25 V, VBATP = 6 V to 28.0 V, unless otherwise noted.
Symbol
Characteristic
Min.
Typ.
Max.
Units
VBATP Supply Voltage POR
• VBATP Supply Power on Reset voltage.
2.7
3.3
3.8
V
VBATP Undervoltage Rising Threshold
—
4.3
4.5
V
VBATP Undervoltage Hysteresis
250
—
500
mV
VBATP Overvoltage Rising Threshold
32
—
37
V
VBATP Overvoltage Hysteresis
1.5
—
3.0
V
VBATP Supply Current
• All switches open, Normal mode, Tri-state disabled (all channels)
—
7.0
12
mA
—
—
—
—
40
40
µA
VBATP Polling Current
• Polling 64 ms, 11 inputs of wake enabled
—
—
20
µA
Normal Mode (IVDDQ)
• SCLK, MOSI, WakeB = 0 V, CS_B, INT_B =VDDQ, no SPI
communication, AMUX selected no input
—
—
500
uA
Logic Low-power Mode Supply Current
• SCLK, MOSI = 0 V, CS_B, INT_B, WAKE_B = VDDQ, no SPI
communication
—
—
10
µA
Ground Offset
• Ground offset of Global pins to IC ground
-1.0
—
1.0
V
VDDQ Undervoltage Falling Threshold
2.2
—
2.8
V
VDDQ Undervoltage Hysteresis
150
—
350
mV
Notes
Power Input
VBATP(POR)
VBATPUV
VBATPUVHYS
VBATPOV
VBATPOVHYS
IBAT(ON)
IBATP,IQ,LPM,P
IBATP,IQ,LPM,F
IPOLLING,IQ
IVDDQ,NORMAL
IVDDQ,LPM
VGNDOFFSET
VDDQUV
VDDQUVHYS
VBATP Low-power Mode Supply Current (polling disabled)
• Parametric VBATP, 6.0 V < VBATP < 28 V
• Functional Low VBATP, 4.5 V < VBATP < 6.0 V
(12)
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
9
Table 6. Static Electrical Characteristics (continued)
TA = - 40 °C to +125 °C, VDDQ = 3.1 V to 5.25 V, VBATP = 6 V to 28.0 V, unless otherwise noted.
Symbol
Characteristic
Min.
Typ.
Max.
Units
ILEAKSG_GND
Leakage (SGx/SPx pins) to GND
• Inputs tri-stated, analog mux selected for each input, voltage at
SGx = VBATP
—
—
2.0
μA
ILEAKSG_BAT
Leakage (SGx/SPx pins) to Battery
• Inputs tri-stated, analog mux selected for each input, voltage at
SGx = GND
—
—
2.0
μA
SG Sustain current / Mode 0 Wetting current
• VBATP 6.0 to 28 V
1.6
2.0
2.4
SG Sustain current / Mode 0 Wetting current LV
• VBATP 4.5 V to 6.0 V
1.0
—
2.4
SB Sustain current / Mode 0 Wetting current
1.75
2.2
2.85
mA
—
mA
%
Notes
Switch Input
ISUSSG
ISUSSGLV
ISUSSB
IWET
IWETSG
Wetting current level (SG & SB)
• Mode 1 = 6mA
• Mode 2 = 8mA
• Mode 3 = 10mA
• Mode 4 = 12mA
• Mode 5 = 14mA
• Mode 6 = 16mA
• Mode 7 = 20mA
—
SG wetting current tolerance
• Mode 1 to 7
6
8
10
12
14
16
20
mA
mA
(13)
-10
—
10
2.0
2.0
2.0
2.0
2.0
2.0
2.0
—
—
—
—
—
—
—
6.6
8.8
11.0
13.2
15.4
17.6
22.0
SB wetting current tolerance
• Mode 1 to 7
-20
—
20
IMATCH(SUS)
Sustain Current Matching Between Channels
—
—
10
%
(14), (15)
IMATCH(WET)
Wetting Current Matching Between Channels
—
—
6.0
%
(16), (17)
Switch Detection Threshold
3.7
4.0
4.3
V
(18)
0.55 *
VBATP
—
4.3
V
IWETSGLV
IWETSB
VICTHR
VICTHRLV
SG wetting current tolerance LV (VBATP 4.5 to
• Mode 1 = 6mA
• Mode 2 = 8mA
• Mode 3 = 10mA
• Mode 4 = 12mA
• Mode 5 = 14mA
• Mode 6 = 16mA
• Mode 7 = 20mA
6.0V)(13)
Switch Detection Threshold Low Battery
• VBATP 4.5 V to 6.0 V
mA
%
VICTHRLPM
Switch Detection Threshold Low Power Mode (SG only)
100
—
300
mV
VICTHRH
Switch Detection Threshold Hysteresis (4.0 V threshold)
80
—
300
mV
VICTH2P5
Input Threshold 2.5 V,
• Used for Comp Only and for AMUX Hardwired Select (SG1/2/3)
2.0
2.5
3.0
V
IACTIVEPOLLSG
Low-power Mode Polling Current SG
• VBATP 4.5 V to 28 V
0.7
1.0
1.44
mA
IACTIVEPOLLSB
Low-power Mode Polling Current SB
1.75
2.2
2.85
mA
(19)
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
10
Table 6. Static Electrical Characteristics (continued)
TA = - 40 °C to +125 °C, VDDQ = 3.1 V to 5.25 V, VBATP = 6 V to 28.0 V, unless otherwise noted.
Symbol
Characteristic
Min.
Typ.
Max.
Units
-2.0
—
2.0
μA
Notes
DIGITAL INTERFACE
IHZ
Tri-state Leakage Current (MISO)
• VDDQ = 0.0 to VDDQ
VINLOGIC
Input Logic Voltage Thresholds
• SI, SCLK, CS_B, INT_B
VDDQ *
0.25
—
VDDQ * 0.7
V
VINLOGICHYS
Input Logic Hysteresis
• SI, SCLK, CS_B, INT_B
300
—
—
mV
VINLOGICWAKE
Input Logic Voltage Threshold WAKE_B
0.8
1.25
1.7
V
VINWAKEBHYS
Input Logic Voltage Hysteresis WAKE_B
200
—
800
mV
ISCLK, IMOSI
SCLK / MOSI Input Current
• SCLK / MOSI = 0 V
-3.0
—
3.0
µA
ISCLK, IMOSI
SCLK / MOSI Pull-down Current
• SCLK / MOSI = VDDQ
30
—
100
µA
ICS_BH
CS_B Input Current
• CS_B = VDDQ
-10
—
10
µA
RCS_BL
CS_B Pull-up Resistor to VDDQ
• CS_B = 0.0 V
40
125
270
k
VOHMISO
MISO High-side Output Voltage
• IOHMISO = -1.0 mA
VDDQ – 0.8
—
VDDQ
V
VOLMISO
MISO Low-side Output Voltage
• IOLMISO = 1.0 mA
—
—
0.4
V
Input Capacitance on SCLK, MOSI, Tri-state MISO (GBD)
—
—
20
pF
-10
-15
—
—
10
15
mV
CIN
Analog MUX Output
VOFFSET
Input Offset Voltage When Selected as Analog
• EK suffix (SOICW)
• ES suffix (QFN at TA = -40 °C to 25 °C)
VOLAMUX
Analog Operational Amplifier Output Voltage
• Sink 1.0 mA
—
—
50
mV
VOHAMUX
Analog Operational Amplifier Output Voltage
• Source 1.0 mA
VDDQ – 0.1
—
—
V
—
8.0
—
mV/°C
(20)
AMUX Selectable Outputs
Temp-Coeff
Chip Temperature Sensor Coefficient
VBATSNSACC
Battery Sense (SG5 config) Accuracy
• Battery voltage (SG5 input) divided by 6
• Accuracy over full temperature range
-5.0
—
5.0
%
VBATSNSDIV
Divider By 6 coefficient accuracy
• Offset over operating voltage range (VBATP=6.0 V to 28 V)
-3.0
—
3.0
%
(21)
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
11
Table 6. Static Electrical Characteristics (continued)
TA = - 40 °C to +125 °C, VDDQ = 3.1 V to 5.25 V, VBATP = 6 V to 28.0 V, unless otherwise noted.
Symbol
Characteristic
Min.
Typ.
Max.
Units
Notes
INT_B
VOLINT
INT_B Output Low Voltage
• IOUT = 1.0 mA
—
0.2
0.5
V
VOHINT
INT_B Output High Voltage
• INT_B = Open-circuit
VDDQ – 0.5
—
VDDQ
V
Pull-up Resistor to VDDQ
40
125
270
k
Leakage Current INT_B
• INT_B pulled up to VDDQ
—
—
1.0
µA
RPU
ILEAKINT_B
Temperature Limit
tFLAG
Temperature Warning
• First flag to trip
105
120
135
°C
tLIM
Temperature Monitor
155
—
185
°C
(22)
Temperature Monitor Hysteresis
5.0
—
15
°C
(22)
RWAKE_B(RPU)
WAKE_B Internal pull-up Resistor to VDDQ
40
125
270
k
VWAKE_B(VOH)
WAKE_B Voltage High
• WAKE_B = Open-circuit
VDDQ -1.0
—
VDDQ
V
VWAKE_B(VOL)
WAKE_B Voltage Low
• WAKE_B = 1.0 mA (RPU to VBATP = 16 V)
—
—
0.4
V
IWAKE_BLEAK
WAKE_B Leakage
• WAKE_B pulled up to VBATP = 16 V through 10 k
—
—
1.0
µA
tLIM(HYS)
WAKE_B
Notes
12. Guaranteed by design
13. During low voltage range operation SG wetting current may be limited when there is not enough headroom between VBATP and SG pin voltage.
14. (ISUS(MAX)– ISUS(MIN)) X 100/ISUS(MIN)
15.
16.
Sustain current source (SGs only)
(IWET(MAX) – IWET(MIN)) X 100/IWET(MIN)
17.
18.
Wetting current source (SGs only)
The input comparator threshold decreases when VBATP ≤ 6.0 V.
19.
SP (as SB) only use the 4.0 V VICTHR for LPM wake-up detection.
20.
For applications requiring a tight AMUX offset through the whole operating range, it is recommended to use the MC33978AEK or MC34978AEK
(SOICW package) variant.
Calibration of divider ratio can be done at VBAT = 12 V, 25 °C to achieve a higher accuracy. See Figure 4 for AMUX offset linearity waveform
through the operating voltage range.
Guaranteed by Characterization in the Development Phase, parameter not tested.
21.
22.
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
12
4.4.2
Dynamic Electrical Characteristics
Table 7. Dynamic Electrical Characteristics
TA = -40 °C to +125 °C. VDDQ = 3.1 V to 5.25 V, VBATP = 4.5 V to 28 V, unless otherwise specified. All SPI timing is performed with a
100 pF load on MISO, unless otherwise noted.
Symbol
Parameter
Min.
Typ.
Max.
Units
POR to Active time
• Undervoltage to Normal mode
250
340
450
µs
Pulse Wetting Current Timer
• Normal mode
17
20
23
ms
Interrupt Delay Time
• Normal mode
—
—
18.5
µs
Polling Timer Accuracy
• Low-power mode
—
—
15
%
Interrupt Timer Accuracy
• Low-power mode
—
—
15
%
49.5
58
66.5
µs
1.0
49.5
1.2
58
1.4
66.5
ms
µs
Notes
General
tACTIVE
Switch Input
tPULSE(ON)
tINT-DLY
tPOLLING_TIMER
tINT-TIMER
tACTIVEPOLLSGTIME Tactivepoll Timer SG
tACTIVEPOLLSBTIME
Tactivepoll Timer SB
• SBPOLLTIME=0
• SBPOLLTIME=1
tGLITCHTIMER
Input Glitch Filter Timer
• Normal mode
5.0
—
18
µs
LPM Debounce Additional Time
• Low-power mode
1.0
1.2
1.4
ms
AMUX Access Time (Selected Output to Selected Output)
• CMUX = 1.0 nF, Rising edge of CS_B to selected
—
(24)
—
μs
AMUX Access Time (Tristate to ON)
• CMUX = 1.0 nF, Rising edge of CS_B to selected
—
—
20
μs
OSCTOLLPM
Oscillator Tolerance at 192 kHz in Low-power Mode
-15
—
15
%
OSCTOLNOR
Oscillator Tolerance Normal Mode at 4.0 MHz
-15
—
15
%
INTPulse Duration
• Interrupt occurs or INT_B request
90
100
110
µs
fOP
Transfer Frequency
—
—
8.0
MHz
tSCK
SCLK Period
• Figure 7 - 1
160
—
—
ns
tLEAD
Enable Lead Time
• Figure 7 - 2
140
—
—
ns
tLAG
Enable Lag Time
• Figure 7 - 3
50
—
—
ns
tSCKHS
SCLK High Time
• Figure 7 - 4
56
—
—
ns
tDEBOUNCE
AMUX Output
AMUXVALID
AMUXVALIDTS
Oscillator
Interrupt
INTPULSE
SPI Interface
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
13
Table 7. Dynamic Electrical Characteristics (continued)
TA = -40 °C to +125 °C. VDDQ = 3.1 V to 5.25 V, VBATP = 4.5 V to 28 V, unless otherwise specified. All SPI timing is performed with a
100 pF load on MISO, unless otherwise noted.
Symbol
Parameter
Min.
Typ.
Max.
Units
Notes
SCLK Low Time
• Figure 7 - 5
56
—
—
ns
tSUS
MOSI Input Setup Time
• Figure 7 - 6
16
—
—
ns
tHS
MOSI Input Hold Time
• Figure 7 - 7
20
—
—
ns
tA
MISO Access Time
• Figure 7 - 8
—
—
116
ns
tDIS
MISO Disable Time (23)
• Figure 7 - 9
—
—
100
ns
tVS
MISO Output Valid Time
• Figure 7 - 10
—
—
116
ns
tHO
MISO Output Hold Time (No cap on MISO)
• Figure 7 - 11
20
—
—
ns
tRO
Rise Time
• Figure 7 - 12
—
—
30
ns
(23)
tFO
Fall Time
• Figure 7 - 13
—
—
30
ns
(23)
tCSN
CS_B Negated Time
• Figure 7 - 14
500
—
—
ns
SPI Interface (Continued)
tSCKLS
Notes
23. Guaranteed by characterization.
24. AMUX settling time to be within the 10 mV offset specification. AMUXVALID is dependant of the voltage step applied on the input SGx/SPx pin or
the difference between the first and second channel selected as the multiplexed analog output. See Figure 9 for a typical AMUX access time VS
voltage step waveform.
Divide By 6 Coefficient Accuracy
6.04
6.03
Divider factor
6.02
6.01
6
25°C
5.99
5.98
5.97
5.96
6
7
8
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
VBATP (Volts)
Figure 4. Divide by 6 Coefficient Accuracy
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
14
LPM CLK
SG_Pin
tglitchTIMER
Input Glitch
filter timer
500ns
tINT- DLY
INT_B
Figure 5. Glitch Filter and Interrupt Delay timers
LPM CLK
SG_Pin
tINT- DLY
INT_B
INTPulse
Figure 6. Interrupt Pulse Timer
3
14
CSb
1
4
2
SCLK
5
10
8
MISO
DATA
MSB OUT
MOSI
MSB IN
LSB OUT
DON'T
CARE
12 13
7
6
9
11
DATA
LSB IN
Figure 7. SPI Timing Diagram
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
15
+5.0 V
VDDQ
4.0 V
MISO
1kohm
1.0 V
MISO
0V
1kohm
9
CS_B
Figure 8. MISO Loading for Disable Time Measurement
AMUX Settling time vs Voltage Step
250
Settling time (us)
200
150
100
AMUX Access Time
50
0
0
500
1000
1500
2000
2500
3000
Step Size (mV)
3500
4000
4500
5000
Figure 9. AMUX Access Time Waveform
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
16
5
General Description
The 33978 is designed to detect the closing and opening of up to 22 switch contacts. The switch status, either open or closed, is
transferred to the microprocessor unit (MCU) through a serial peripheral interface (SPI). Individually selectable input currents are available
in Normal and Low-power (LPM) modes, as needed for the application.
It also features a 24-to-1 analog multiplexer for reading inputs as analog. The analog input signal is buffered and provided on the AMUX
output pin for the MCU to read. A battery and temperature monitor are included in the IC and available via the AMUX pin.
The 33978 device has two modes of operation, Normal and Low Power mode (LPM). Normal mode allows programming of the device and
supplies switch contacts with pull-up or pull-down current as it monitors the change of state of switches. The LPM provides low quiescent
current, which makes the 33978 ideal for automotive and industrial products requiring low sleep-state currents.
5.1
Features
•
•
•
•
•
•
•
Fully functional operation from 4.5 V to 36 V
Full parametric operation from 6.0 V to 28 V
Low-power mode current IBATP = 30 A and IDDQ = 10 A
22 Switch detection channels
•
14 Switch-to-Ground (SG) inputs
•
Eight Programmable switch (SP) inputs
• Switch-to-Ground (SG) or Switch-to-Battery (SB)
•
Operating switch input voltage range from -1.0 V to 36 V
•
Selectable wetting current (2, 6, 8, 10, 12, 14, 16, or 20 mA)
•
Programmable wetting operation (Pulse or Continuous)
•
Selectable wake-up on change of state
24 to 1 Analog Multiplexer
•
Buffered AMUX output from SG/SP channels
•
Integrated divider by 6 on SG5 for battery voltage sensing
•
Integrated die temperature sensing through AMUX output
•
Two or three pin hardwire AMUX selection.
Active interrupt (INT_B) on change-of-switch state
Direct MCU Interface through 3.3 V / 5.0 V SPI protocol
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
17
5.2
Functional Block Diagram
33978 Functional Internal Block Diagram
Switch Status Detection
Input Power
VBATP
Battery Supply
VDDQ
Logic Supply
Bias & References
1.25 V internal Bandgap
4.0 V SW detection reference.
192 kHz
LPM Oscillator
4.0 MHz
Oscillator
8 x Programmable Switch
SG0 – SG13
SP0 – SP7
Switch to Ground (SG)
Only
Switch to Ground (SG)
Switch to Battery (SB)
Selectable Wetting Current Level
Pulse/Continuous Wetting Current
Analog Multiplexer (AMUX)
Logic and Control
WAKE_B I/O
14 x Switch to Ground
INT_B I/O
SPI Serial Communication & Registers
24 to 1 SPI AMUX select
Hardwire selectable
SPx/SGx Inputs to AMUX
Battery Voltage sensing (divided by 6 )
Fault Detection and Protection
Over Temperature
Protection
OV Detection
VBATP UV detect
SPI Error detect
HASH error detect
Die Temperature Sensing
Modes of Operation
Normal Mode
Low Power Mode
SPI communication/
Switch status read
Programmable Polling/
Interrupt Time
Figure 10. Functional Block Diagram
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
18
6
General IC Functional Description
The 33978 device interacts with many connections outside the module and near the end user. The IC detects changes in switch state and
reports the information to the MCU via the SPI protocol. The input pins generally connected to switches located outside the module and
in proximity to battery in car harnesses. Consequently, the IC must have some external protection including an ESD capacitor and series
resistors, to ensure the energy from the various pulses are limited at the IC.
The IC requires a blocking diode be used on the VBATP pin to protect from a reverse battery condition. The inputs are capable of surviving
reverse battery without a blocking diode and also contain an internal blocking diode from the input to the power supply (VBATP), to ensure
there is no backfeeding of voltage/current into the IC, when the voltage on the input is higher than the VBATP pin.
6.1
Battery Voltage Ranges
The 33978 device operates from 4.5 V ≤ VBATP ≤ 36 V and is capable to withstand up to 40 V. The IC operates functionally from 
4.5 V < VBATP < 6.0 V, but with degraded parametrics values. Voltages in excess of 40 V must be clamped externally in order to protect
the IC from destruction. The VBATP pin must be isolated from the main battery node by a diode.
6.1.1
Load Dump (Over voltage)
During load dump the 33978 operates properly up to the VBATP overvoltage. Voltages greater than load dump (~32 V) causes the current
sources to be limited to ~2.0 mA, but the register values are maintained. Upon leaving this overvoltage condition, the original setup is
returned and normal operation begins again.
6.1.2
Jump Start (Double Battery)
During a jump start (double battery) condition, the device functions normally and meets all the specified parametric values. No internal
faults are set and no abnormal operation noted as a result of operating in this range.
6.1.3
Normal Battery Range
The normal voltage range is fully functional with all parametrics in the given specification.
6.1.4
Low Voltage Range (Degraded Parametrics)
In the VBATP range between 4.5 V to 6.0 V the 33978 functions normally, but has some degraded parametric values. The SPI functions
normally with no false reporting. The degraded parameters are noted in Table 6 and Table 7. During this condition, the input comparator
threshold is reduced from 4.0 V and remain ratiometrically adjusted, according to the battery level.
6.1.5
Undervoltage Lockout
During undervoltage lockout, the MISO output is tri-stated to avoid any data from being transmitted from the 33978. Any CS_B pulses are
ignored in this voltage range. If the battery enters this range at any point (even during a SPI word), the 33978 ignores the word and enters
lockout mode. A SPI bit register is available to notify the MCU that the 33978 has seen an undervoltage lockout condition once the battery
is high enough to leave this range.
6.1.6
Power On Reset (POR) Activated
The Power on Reset is activated when the VBATP is within the 2.7 V to 3.8 V range. During the POR all SPI registers are reset to default
values and SPI operation is disabled. The 33978 is initialized after the POR is de-asserted. A SPI bit in the device configuration register
is used to note a POR occurrence and all SPI registers are reset to the default values.
6.1.7
No Operation
The device does not function and no switch detection is possible.
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
19
VBATP
(IC Level)
Battery Voltage
(System Level)
41 V
40 V
Overvoltage
Over Voltage
37 V
36 V
Load Dump
Functional
29 V
28 V
Normal Mode
Full Parametrics
Normal
Battery
6.0 V
7.0 V
Degraded Parametrics
Low Battery
5.5 V
Undervoltage lockout
POR
No Operation
5.3 V
3.7 V
0V
4.5 V
4.3 V
2.7 V
Reset
0V
Figure 11. Battery Voltage Range
6.2
Power Sequencing Conditions
The chip uses two supplies as inputs into the device for various usage. The pins are VBATP and VDDQ. The VBATP pin is the power
supply for the chip where the internal supplies are generated and power supply for the SG circuits. The VDDQ pin is used for the I/O buffer
supply to talk to the MCU or other logic level devices, as well as AMUX. The INT_B pin is held low upon POR until the IC is ready to
operate and communicate. Power can be applied in various ways to the 33978 and the following states are possible:
6.2.1
VBATP Before VDDQ
The normal condition for operation is the application of VBATP and then VDDQ. The chip begin to operate logically in the default state but
without the ability to drive logic pins. When the VDDQ supply is available the chip is able to communicate correctly. The IC maintains its
logical state (register settings) with functional behavior consistent with logical state. No SPI communications can occur.
6.2.2
VDDQ Before VBATP
The VDDQ supply in some cases may be available before the VBATP supply is ready. In this scenario, there is no back feeding current into
the VDDQ pin that could potentially turn on the device into an unknown state. VDDQ is isolated from VBATP circuits and the device is off
until VBATP is applied; when VBATP is available the device powers up the internal rails and logic within tACTIVE time. Communication is
undefined until the tACTIVE time and becomes available after this time frame.
6.2.3
VBATP Okay, VDDQ Lost
After power up, it is possible that the VDDQ may turn off or be lost. In this case, the chip will remain in the current state but is not able to
communicate. After the VDDQ pin is available again, the chip is ready to communicate.
6.2.4
VDDQ Okay, VBATP Lost
After power up, the VBATP supply could be lost. The operation is consistent as when VDDQ is available before VBATP.
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
20
7
Functional Block Description
7.1
State Diagram
IC OFF
VBATP applied
RESET
VBAT applied >
por
VBATP > UV
threshold
Wait 50 s
Read fuses
VBAT too low:
POR
SPI RESET
command
UV
OV / OT
Iwet-> Isus
VBATP > OV
or OT
VBATP <
UV
Not VBATP > OV
or OT
Run
Normal Mode
Detect change in switch
status (opn/close)
Wake
Event
SPI CMD
Polling time expires
Low Power
Mode
Polling
Polling timer initiates
Figure 12. 33978 State Diagram
7.1.1
State Machine
After power up, the IC enters into the device state machine, as illustrated in Figure 12. The voltage on VBATP begins to power the internal
oscillators and regulator supplies. The POR is based on the internal 2.5 V digital core rail. When the internal logic regulator reaches
approximately 1.8 V (typically 3.3 V on the VBATP node), the IC enters into the UV range. Below the POR threshold, the IC is in RESET
mode where no activity occurs.
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
21
7.1.2
UV: Undervoltage Lockout
After the POR circuit has reset the logic, the IC is in undervoltage. In this state, the IC remembers all register conditions, but is in a lockout
mode, where no SPI communication is allowed. The AMUX is inactive and the current sources are off. The user does not receive a valid
response from the MISO, as it is disabled in this state. The chip oscillators (4.0 MHz for most normal mode activities, 192 kHz for LPM,
and limited normal mode functions) are turned on in the UV state. The chip moves to the Read fuses state when the VBATP voltage rises
above the UV threshold (~4.3 V rising). The internal fuses read in approximately 50 s and the chip enters the Normal mode.
7.1.3
Normal Mode
In normal mode, the chip operates as selected in the available registers. Any command may be loaded in normal mode, although not all
(Low-power mode) registers are used in the Normal mode. All the LPM registers must be programmed in Normal mode as the SPI is not
active in LPM. The Normal mode of the chip is used to operate the AMUX, communicate via the SPI, Interrupt the IC, wetting and sustain
currents, as well as the thresholds available to use. The WAKE_B pin is asserted (low) in Normal mode and can be used to enable a power
supply (ENABLE_B). Various fault detections are available in this mode including overvoltage, overtemperature, thermal warning, SPI
errors, and Hash faults.
7.1.4
Low Power Mode
When the user needs to lower the IC current consumption, a low-power mode is used. The only method to enter LPM is through a SPI
word. After the chip is in low-power mode, the majority of circuitry is turned off including most power rails, the 4.0 MHz oscillator, and all
the fault detection circuits. This mode is the lowest current consumption mode on the chip. If a fault occurs while the chip is in this mode,
the chip does not see or register the fault (does not report via the SPI when awakened). Some items may wake the IC in this mode,
including the interrupt timer, falling edge of INT_B, CS_B, or WAKE_B (configurable), or a comparator only mode switch detection.
7.1.5
Polling Mode
The 33978 uses a polling mode which periodically (selectable in LPM config register) interrogates the input pins to determine in what state
the pins are, and decide if there was a change of state from when the chip was in Normal mode. There are various configurations for this
mode, which allow the user greater flexibility in operation. This mode uses the current sources to pull-up (SG) or down (SB) to determine
if a switch is open or closed. More information is available in section 7.2, “Low-power Mode Operation".
In the case of a low VBATP, the polling pauses and waits until the VBATP rises out of UV or a POR occurs. The pause of the polling ensures
all of the internal rails, currents, and thresholds are up at the required levels to accurately detect open or closed switches. The chip does
not wake-up in this condition and simply waits for the VBATP voltage to rise or cause a POR.
After the polling ends, the chip either returns to the low-power mode, or enters Normal mode when a wake event was detected. Other
events may wake the chip as well, such as the falling edge of CS_B, INT_B, or WAKE_B (configurable). A comparator only mode switch
detection is always on in LPM or Polling mode, so a change of state for those inputs would effectively wake the IC in Polling mode as well.
If the Wake-up enable bits are disable on all channels (SG and SP) the device will not wake up with a change of state on any of the input
pins; in this case, the device will disable the polling timer to allow the lowest current consumption during low power mode.
7.2
Low-power Mode Operation
Low-power mode (LPM) is used to reduce system quiescent currents. LPM may be entered only by sending the Enter Low-power mode
command. All register settings programmed in Normal mode are maintained while in LPM.
The 33978 exits LPM and enter Normal mode when any of the following events occur:
• Input switch change of state (when enabled)
• Interrupt timer expire
• Falling edge of WAKE_B (as set by the device configuration register)
• Falling edge of INT_B (with VDDQ = 5.0 V)
• Falling edge of CS_B (with VDDQ = 5.0 V)
• Power-ON Reset (POR)
The VDDQ supply may be removed from the device during LPM, however removing VDDQ from the device disables a wake-up from falling
edge of INT_B and CS_B. The IC checks the status of VDDQ after a falling edge of WAKE_B (as selected in the device configuration
register), INT_B and CS_B. The IC returns to LPM and does not report a Wake event, if VDDQ is low. If the VDDQ is high, the IC wakes up
and reports the Wake event. In cases where CS_B is used to wake the device, the first MISO data message is not valid.
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
22
The LPM command contains settings for two programmable registers: the interrupt timer and the polling timer, as shown in Table 26. The
interrupt timer is used as a periodic wake-up timer. When the timer expires, an interrupt is generated and the device enters Normal mode.
The polling timer is used periodically to poll the inputs during Low-power mode to check for change of states. The tACTIVEPOLL time is the
length of time the part is active during the polling timer to check for change of state. The Low-power mode voltage threshold allows the
user to determine the noise immunity versus lower current levels that polling allows. Figure 14 shows the polling operation.
When polling and Interrupt timer coincide, the Interrupt timer wakes the device and the polling does not occur. When an input is determined
to meet the condition Open (when entering LPM), yet while Open (on polling event) the chip does not continue the polling event for that
input(s) to lower current in the chip (Figure 13 shows SG, SB is logically the same).
Compare voltage to initial
(Delta > 0.25 or > 4.0v)
End Polling (current off if
no change detected)
LPM Voltage threshold
(~0.25v)
La
tc
h
vo
lt a
ge
Voltage on SG pin
55µs
Polling timer
(64ms def)
Figure 13. Low-power mode polling check
Go To LPM
CS_B
64ms (config)
Normal
Normal
Mode
LPM
Polling Time
20us
Polling startup
78us
Tactive time
58us
330uA
IC Current
20uA
X * 1mA SG
(2mA SB)
Load
Current
0uA
Figure 14. Low-power Mode Typical Timing
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
23
VBATP
VDDQ
Wake up from Interrupt
Timer expire
WAKE_B
INT_B
CS_B
Wake up from
Closed Switch
SGn
Power – up
Normal Mode
Tri- state
Command
Sleep
Command
Sleep Mode
Normal
Mode
Sleep
Command
Sleep Mode
Normal
Mode
Sleep
Command
Figure 15. Low-power Mode to Normal Mode Operation
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
24
7.3
Input Functional Block
The SGx pins are switch-to-ground inputs only (pull-up current sources).
The SPx pins are configurable as either switch to ground or switch to battery (pull-up and pull-down current sources).
The input is compared with a 4.0 V (input comparator threshold configurable) reference. Voltages greater than the input comparator
threshold value are considered open for SG pins and closed for SB configuration.
Voltages less than the input comparator threshold value are considered closed for SG pins and open for the SB configurations.
Programming features are defined in the SPI Control Register Definition section of this datasheet.
The input comparator has hysteresis with the thresholds based on the closing of the switch (falling on SG, rising on SB).
The user must take care to keep power conditions within acceptable limits (package is capable of 2.0 W). Using many of the inputs with
continuous wetting current levels causes overheating of the IC and may cause an overtemperature (OT) event to occur.
VBATP
Pre-reg = ~8v
6 - 20
mA
2.0
mA
1.0mA
(LPM)
To AMUX
To SPI
4.0 V ref comparator
Or
250mV Delta V
Or
2.5v Comparator only
Figure 16. SG Block diagram
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
25
VBATP
Pre-reg
6 - 20
mA
2.0
mA
1.0mA
(LPM)
To SPI
4.0 V ref comparator
6 - 20
mA
2.0
mA
21.0mA
(LPM)
Figure 17. SP Block diagram
7.4
Oscillator and Timer Control Functional Block
Two oscillators are generated in this block. A 4.0 MHz clock is used in Normal mode only, as well as a Low-power mode 192 kHz clock,
which is on all the time. All timers are generated from these oscillators. The oscillator accuracy is 15% for both, the 4.0 MHz clock and the
192 kHz clock. No calibration is needed and the accuracy is over voltage and temperature.
7.5
Temperature Monitor and Control Functional Block
The device has multiple thermal limit (tLIM) cells to detect thermal excursions in excess of 155 °C. The tLIM cells from various locations on
the IC are logically ORed together and communicated to the MCU as one tLIM fault. When the tLIM value is seen, the wetting current is
lowered to 2.0 mA until the temperature has decreased beyond the tLIM(HYS) value (the sustain current remains on or as selected). A
hysteresis value of 15 °C exists to keep the device from cycling.
A thermal flag also exists to alert the system to increasing temperatures more than approximately 120 °C.
7.6
WAKE_B Control Functional Block
The WAKE_B pin can operate as an open-drain output or a wake-up input. In the Normal Mode, the WAKE_B pin is LOW. In the Low
power mode, the WAKE_B pin is pulled HIGH. The WAKE_B pin has an internal pull-up to VDDQ supply with an internal series diode to
allow an external pull-up to VBATP if required.
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
26
As an input, in Low power mode with the WAKE_B pin pulled HIGH, when commanded LOW by MCU, the falling edge of WAKE_B will
place the MC33978 in Normal Mode. In Low power mode if VDDQ goes low, the WAKE_B pin can still wake the device based on the
status of the WAKE_B bit in the device configuration register, this allows the user to pull the WAKE_B pin up to VBATP such that it can
be used in VDDQ off setup.
As an output, WAKE_B pin can drive either an MCU input or the EnableB of a regulator (possibly for VDDQ). WAKE_B is driven Low during
Normal mode regardless of the state of VDDQ. When the 33978 is in LPM, the WAKE_B pin is released and is expected to be pulled up
internally to VDDQ or externally to VBATP. When a valid wake-up event is detected, the 33978 wakes up from LPM and the WAKE_B is
driven Low (regardless of the state of VDDQ).
7.7
INT_B Functional Block
INT_B is an input/output pin in the 33978 device to indicate an interrupt event has occurred, as well as receiving interrupts from other
devices when the INT_B pins are wired ORed. The INT_B pin is an open-drain output with an internal pull-up to VDDQ. In Normal mode,
a switch state change triggers the INT_B pin (when enabled). The INT_B pin and INT_B bit in the SPI register are latched on the falling
edge of CS_B. This permits the MCU to determine the origin of the interrupt. When two 33978 devices are used, only the device initiating
the interrupt has the INT_B bit set. The INT_B pin and INTflg bit are cleared 1.0 s after the falling edge of CS B. The INT_B pin does not
clear with the rising edge of CS_B if a switch contact change has occurred while CS_B was Low.
In a multiple 33978 device system with WAKE_B High and VDDQ on (Low-power mode), the falling edge of INT_B places all 33978s in
Normal mode. The INT_B has the option of a pulsed output (pulsed low for INTpulse duration) or a latched low output. The default case is
the latched low operation; the pulsed option is selectable via the SPI.
An INT_B request by the MCU can be done by a SPI word and results in an INTPULSE of 100 s duration on the INT_B pin.
The chip causes an INT_B assertion for the following cases:
1. A change of state is detected
2. Interrupt timer expires
3. Any Wake-up event
4. Any faults detected
5. After a POR, the INT_B pin states asserted during startup until the chip is ready to communicate
7.8
AMUX Functional Block
The analog voltage on switch inputs may be read by the MCU using the analog command (Table 43). Internal to the IC is a 24-to-1 analog
multiplexer. The voltage present on the selected input pin is buffered and made available on the AMUX output pin. The output pin is
clamped to a maximum of VDDQ regardless of the higher voltages present on the input pin. After an input has been selected as the analog,
the corresponding bit in the next MISO data stream is logic [0]. When selecting a channel to be read as analog input, the user can also
set the current level allowed in the AMUX output. Current level can be set to the programmed wetting current for the selected channel or
set to high-impedance as defined in Table 42.
When selecting an input to be sent to the AMUX output, that input is not polled or a wake-up enabled input from Low-power mode. The
user should set the AMUX to “No input selected” or “Temp diode” before entering Low-power mode. The AMUX pin is not active during
Low-power mode. The SG5 pin can also be used as a VBATP sense pin. An internal resistor divider of 1/6 is provided for conditioning the
VBATP higher voltage to a level within the 0 V to VDDQ range.
Besides the default SPI input selection method, the AMUX has two hardwire operation such that the user can select an specific input
channel by physically driving the SG1, SG2 or SG3 pin (HW 3-bit), or by driving the SG1 and SG2 pins (HW 2-bit) as shown in Table 9
and Table 10. When using the AMUX hardwired options, the SG1, SG2, and SG3 inputs use a 2.5 V input voltage threshold to read a
logic 0 or logic 1.
Table 8 shows the AMUX selection methods configurable by the Aconfig0 and Aconfig1 bits in the Device Configuration register.
Table 8. AMUX Selection Method
Aconfig1
Aconfig0
AMUX Selection method
0
0
SPI (def)
0
1
SPI
1
0
HW 2-bit
1
1
HW 3-bit
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
27
Table 9. AMUX Hardware 3-bit
Pins [SG3, SG2, SG1]
Output of AMUX
000
SG0
001
SG5
010
SG6
011
SG7
100
SG8
101
SG9
110
Temperature Diode
111
Battery Sense
Table 10. AMUX Hardware 2-bit
Pins [SG2, SG1]
Output of AMUX
00
SG0
01
SG5
10
SG6
11
SG7
Since the device is required to meet the ±1.0 V offset with ground, it is imperative that the user bring the sensor ground back to the 33978
when using the AMUX for accurate measurements to ensure any ground difference does not impact the device operation.
7.9
Serial Peripheral Interface (SPI)
The 33978 contains a serial peripheral interface consisting of Serial Clock (SCLK), Serial Data Out (MISO), Serial Data In (MOSI), and
Chip Select Bar (CS_B). The SPI interface is used to provide configuration, control, and status functions; the user may read the registers
contents as well as read some status bits of the IC. This device is configured as an SPI slave.
All SPI transmissions to the 33978 must be done in exact increments of 32 bits (modulo 0 is ignored as well). The 33978 contains a data
valid method via SCLK input to keep non-modulo-32 bit transmissions from being written into the IC. The SPI module also provides a daisy
chain capability to accommodate MOSI to MISO wrap around (see Figure 21).
The SPI registers have a hashing technique to ensure that the registers are consistent with the programmed values. If the hashed value
does not match the register status, a SPI bit is set as well as an interrupt to alert the MCU to this issue.
7.9.1
Chip Select Low (CS_B)
The CS_B input selects this device for serial transfers. On the falling edge of CS_B, the MISO pin is released from tri-state mode, and all
status information are latched in the SPI shift register. While CS_B is asserted, register data is shifted in the MOSI pin and shifted out the
MISO pin on each subsequent SCLK. On the rising edge of CS_B, the MISO pin is tri-stated and the fault register reloaded (latched) with
the current filtered status data. To allow sufficient time to reload the fault registers, the CS_B pin must remain low for a minimum of tCSN
prior to going high again.
The CS_B input contains a pull-up current source to VDDQ to command the de-asserted state should an open-circuit condition occur.
This pin has threshold compatible voltages allowing proper operation with microprocessors using a 3.3 V to 5.0 V supply.
7.9.2
Serial Clock (SCLK)
The SCLK input is the clock signal input for synchronization of serial data transfer. This pin has a threshold compatible voltages allowing
proper operation with microprocessors using a 3.3 V to 5.0 V supply.
When CS_B is asserted, both the Master Microprocessor and this device latch input data on the rising edge of SCLK. The SPI master
typically shifts data out on the falling edge of SCLK, while this device shifts data out on the rising edge of SCLK, to allow more time to
drive the MISO pin to the proper level.
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
28
This input is used as the input for the modulo-32 bit counter validation. Any SPI transmissions which are NOT exact multiples of 32 bits
(i.e. clock edges) is treated as an illegal transmission. The entire frame is aborted and no information is changed in the configuration or
control registers.
7.9.3
Serial Data Output (MISO)
The MISO output pin is in a tri-state condition when CS_B is negated. When CS_B is asserted, MISO is driven to the state of the MSB of
the internal register and start shifting out the requested data from the MSB to the LSB. This pin supplies a “rail to rail” output, depending
on the voltage at the VDDQ pin.
7.9.4
Serial Data Input (MOSI)
The MOSI input takes data from the master microprocessor while CS_B is asserted. The MSB is the first bit of each word received on
MOSI and the LSB is the last bit of each word received on MOSI. This pin has threshold level compatible input voltages allowing proper
operation with microprocessors using a 3.3 V to 5.0 V (VDDQ) supply.
CS_B
Control word
Configure words
MOSI/
SCLK
31
30
29 28
27 26
25
24
23
22
21
20 ... 3
2
1
0
MISO
INTflg
Switch Status Register
Fault Status
SG/SP input status
Figure 18. First SPI Operation (After POR)
CS_B
CS_B
Control word
Next Control word
Configure word
Next Configure words
MOSI/
SCLK
MOSI/
SCLK
31
30
29 28
27 26
25
24
23
22
21
20 ... 3
2
MISO
1
0
31
30
29 28
27 26
25
24
23
22
21
20 ... 3
2
1
0
MISO
Previous Address
Previous command data
Control Word
Configure Word
Figure 19. SPI Write Operation
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
29
CS_B
CS_B
Control word (READ)
Next Control word
DON’T CARE
Next Configure words
MOSI/
SCLK
MOSI/
SCLK
31
30
29 28
27 26
25
24
23
22
21
20 ... 3
2
MISO
1
0
31
30
29 28
27 26
25
24
23
22
21
20 ... 3
2
1
0
MISO
Previous command data
Previous Address
Control Word (READ)
Register Data
Figure 20. SPI Read Operation
CSb
SCLK
DI
DO
1 st IC
CSb
SCLK
MISO
MISI
MCU
CSb
SCLK
DI
DO
2 nd IC
CSb
SCLK
DI
DO
3 rd IC
CSb
Don' t Care
MOSI - 3 rd IC MOSI- 2 nd IC MOSI- 1 st IC
MOSI - 1 st IC
MCU MISO
MISO - 1 st IC
MOSI - 2 nd IC
MISO - 2 st IC
MOSI - 3 rd IC
MISO - 3 rd IC
MCU MOSI
MISO - 3 rd IC
MISO - 2 nd IC MISO - 1 st IC
Don' t Care
Figure 21. Daisy Chain SPI Operation
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
30
7.10
SPI Control Register Definition
A 32-bit SPI allows the system microprocessor to configure the 33978 for each input as well as read out the status of each input. The SPI
also allows the Fault Status and INTflg bits to be read via the SPI. The SPI MOSI bit definitions are given in Table 11:
Table 11. MOSI Input Register Bit Definition
Register #
0
Register Name
Address
Rb/W
SPI Check
0
0
0
0
0
0
0
0
02/03
Device Configuration Register
0
0
0
0
0
0
1
0/1
04/05
Tri-state SP Register
0
0
0
0
0
1
0
0/1
06/07
Tri-state SG Register
0
0
0
0
0
1
1
0/1
08/09
Wetting Current Level SP Register
0
0
0
0
1
0
0
0/1
0A/0B
Wetting Current Level SG Register 0
0
0
0
0
1
0
1
0/1
0C/0D
Wetting Current Level SG Register 1
0
0
0
0
1
1
0
0/1
16/17
Continuous Wetting Current SP Register
0
0
0
1
0
1
1
0/1
18/19
Continuous Wetting Current SG Register
0
0
0
1
1
0
0
0/1
1A/1B
Interrupt Enable SP Register
0
0
0
1
1
0
1
0/1
1C/1D
Interrupt Enable SG Register
0
0
0
1
1
1
0
0/1
1E/1F
Low-power Mode Configuration
0
0
0
1
1
1
1
0/1
20/21
Wake-up Enable Register SP
0
0
1
0
0
0
0
0/1
22/23
Wake-up Enable Register SG
0
0
1
0
0
0
1
0/1
24/25
Comparator Only SP
0
0
1
0
0
1
0
0/1
26/27
Comparator Only SG
0
0
1
0
0
1
1
0/1
28/29
LPM Voltage Threshold SP Configuration
0
0
1
0
1
0
0
0/1
2A/2B
LPM Voltage threshold SG Configuration
0
0
1
0
1
0
1
0/1
2C/2D
Polling Current SP Configuration
0
0
1
0
1
1
0
0/1
2E/2F
Polling Current SG Configuration
0
0
1
0
1
1
1
0/1
30/31
Slow Polling SP
0
0
1
1
0
0
0
0/1
32/33
Slow Polling SG
0
0
1
1
0
0
1
0/1
34/35
Wake-up Debounce SP
0
0
1
1
0
1
0
0/1
36/37
Wake-up Debounce SG
0
0
1
1
0
1
1
0/1
39
Enter Low-power Mode
0
0
1
1
1
0
0
1
3A/3B
AMUX Control Register
0
0
1
1
1
0
1
0/1
3E
Read Switch Status
0
0
1
1
1
1
1
0
42
Fault Status Register
0
1
0
0
0
0
1
0
47
Interrupt Request
0
1
0
0
0
1
1
1
49
Reset Register
0
1
0
0
1
0
0
1
The 32-bit SPI word consists of a command word (8-bit) and three configure words (24-bit). The 8 MSB bits are the command bits that
select what type of configuration is to occur. The remaining 24-bits are used to select the inputs to be configured.
• Bit 31 - 24 = Command word: Use to select what configuration is to occur (example: setting wake-up enable command)
• Bit 23 - 0 = SGn input select word: Use these bits in conjunction with the command word to determine which input is setup.
Configuration registers may be read or written to. To read the contents of a configuration register, send the register address + ‘0’ on the
LSB of the command word; the contents of the corresponding register will be shifted out of the MISO buffer in the next SPI cycle. When
a Read command is sent, the answer (in the next SPI transaction) includes the Register address in the upper byte (see Figure 20).
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
31
Read example:
• Send 0x0C00_0000 Receive: 8000_0000 (for example after a POR)
• Send 0x0000_0000 Receive: 0C00_0000 (address + register data)
The first response from the device after a POR event is a Read Status register (0x3Exxxxxx where x is the status of the inputs). This is
the same for exiting the Low Power mode (see Figure 18.).
To write into a configuration register, send the register Address + ‘1’ on the LSB of the command word and the configuration data on the
next 24 bits. The new value of the register will be shifted out of the MISO buffer in the next SPI cycle, along with the register address.
Table 7.10.1 provides a general overview of the functional SPI commands and configuration bits.
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
0
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
0000001
0/1
FS
INT
X
X
X
X
X
X
X
X
aconfig1
0000000
Device Configuration
X
X
X
X
X
SP7
SPI check
SP0
16
SP1
17
SP2
18
SP3
19
SP4
20
SP5
21
IntB_Out
24
R/W
SP6
22
WAKE_B Pull up
[31-25]
Address
aconfig0
23
VBATP OV Disable
Commands
SBPOLL TIME
Table 12. Functional SPI Register Map
Tri-State Enable SP
0000010
0/1
FS
INT
X
X
X
X
X
X
X
X
Tri-State Enable SG
0000011
0/1
FS
INT
X
X
X
X
X
X
X
X
Wetting Current Level SP
0000100
0/1
SP7[2-0]
SP6[2-0]
SP5[2-0]
SP4[2-0]
SP3[2-0]
SP2[2-0]
SP1[2-0]
SP0[2-0]
Wetting Current Level SG 0
0000101
0/1
SG7[2-0]
SG6[2-0]
SG5[2-0]
SG4[2-0]
SG3[2-0]
SG2[2-0]
SG1[2-0]
SG0[2-0]
Wetting Current Level SG 1
0000110
0/1
FS
INT
X
X
X
X
SG13[2-0]
SG12[2-0]
SG11[2-0]
SG10[2-0]
SG9[2-0]
SG8[2-0]
Continuous Wetting Current
Enable SP
0001011
0/1
FS
INT
X
X
X
X
X
X
X
X
Continuous Wetting Current
Enable SG
0001100
0/1
FS
INT
X
X
X
X
X
X
X
X
Interrupt Enable SP
0001101
0/1
FS
INT
X
X
X
X
X
X
X
X
Interrupt Enable SG
0001110
0/1
FS
INT
X
X
X
X
X
X
X
X
Low Power Mode
configuration
0001111
0/1
FS
INT
X
X
X
X
X
X
X
X
Wake-Up Enable SP
0010000
0/1
FS
INT
X
X
X
X
X
X
X
X
Wake-Up Enable SG
0010001
0/1
FS
INT
X
X
X
X
X
X
X
X
LPM Comparator Only SP
0010010
0/1
FS
INT
X
X
X
X
X
X
X
X
LPM Comparator Only SG
0010011
0/1
FS
INT
X
X
X
X
X
X
X
X
LPM Voltage Threshold SP
0010100
0/1
FS
INT
X
X
X
X
X
X
X
X
LPM Voltage Threshold SG
0010101
0/1
FS
INT
X
X
X
X
X
X
X
X
LPM Polling current config
SP
0010110
0/1
FS
INT
X
X
X
X
X
X
X
X
LPM Polling current config
SG
0010111
0/1
FS
INT
X
X
X
X
X
X
X
X
LPM Slow Polling SP
0011000
0/1
FS
INT
X
X
X
X
X
X
X
X
LPM Slow Polling SG
0011001
0/1
FS
INT
X
X
X
X
X
X
X
X
Wake-Up Debounce SP
0011010
0/1
FS
INT
X
X
X
X
X
X
X
X
Wake-Up Debounce SG
0011011
0/1
FS
INT
X
X
X
X
X
X
X
X
SG13 SG12 SG11 SG10 SG9
X
X
X
X
X
SG13 SG12 SG11 SG10 SG9
X
X
X
X
X
SG13 SG12 SG11 SG10 SG9
X
X
X
X
X
X
X
X
X
X
SG13 SG12 SG11 SG10 SG9
X
X
X
X
X
SG13 SG12 SG11 SG10 SG9
X
X
X
X
X
SG13 SG12 SG11 SG10 SG9
X
X
X
X
X
SG13 SG12 SG11 SG10 SG9
X
X
X
X
X
SG13 SG12 SG11 SG10 SG9
X
X
X
X
X
SP7
SP6
SP5
SP4
SP3
SP2
SP1
SP0
SG7
SG6
SG5
SG4
SG3
SG2
SG1
SG0
X
SP7
SP6
SP5
SP4
SP3
SP2
SP1
SP0
SG8
SG7
SG6
SG5
SG4
SG3
SG2
SG1
SG0
X
SP7
SP6
SP5
SP4
SP3
SP2
SP1
SP0
SG8
SG7
SG6
SG5
SG4
SG3
SG2
SG1
SG0
X
int3
int2
int2
int0
poll3
poll2
poll1
poll0
X
SP7
SP6
SP5
SP4
SP3
SP2
SP1
SP0
SG8
SG7
SG6
SG5
SG4
SG3
SG2
SG1
SG0
X
SP7
SP6
SP5
SP4
SP3
SP2
SP1
SP0
SG8
SG7
SG6
SG5
SG4
SG3
SG2
SG1
SG0
X
SP7
SP6
SP5
SP4
SP3
SP2
SP1
SP0
SG8
SG7
SG6
SG5
SG4
SG3
SG2
SG1
SG0
X
SP7
SP6
SP5
SP4
SP3
SP2
SP1
SP0
SG8
SG7
SG6
SG5
SG4
SG3
SG2
SG1
SG0
X
SP7
SP6
SP5
SP4
SP3
SP2
SP1
SP0
SG8
SG7
SG6
SG5
SG4
SG3
SG2
SG1
SG0
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Read Switch Status
0011111
0
SP1
SP0
SG13
SG12
SG11
SG10
SG9
SG8
SG7
SG6
SG5
SG4
SG3
SG2
SG1
SG0
Fault Status
0100001
0
X
X
X
X
X
SPI Error
hash fault
X
UV
OV
TempFlag
OT
INT_B wake
WAKE_B
SpiWake
POR
X
X
X
X
X
X
INT
SP2
X
INT
FS
X
X
FS
0/1
SP3
X
1
0011101
X
X
0011100
SP4
X
Enter Low Power Mode
AMUX Channel Select SPI
X
SP0
SG0
SP5
SP1
SG1
X
SP2
SG2
SP6
SP3
SG3
X
SP4
SG4
SP7
SP5
SG5
X
SP6
SG6
INTflg
SP7
SG7
INTflg
X
SG8
FAULT STATUS
SG13 SG12 SG11 SG10 SG9
X
SG8
Interrupt Pulse Request
0100011
1
FS
INT
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Reset
0100100
1
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
asett asel5 asel4 asel3 asel2 asel1 asel0
Notes
25. FS = FAULT STATUS (available for reading on MISO return word)
26. INT = INTflg (available for reading on MISO return word)
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
32
7.10.1
SPI Check
The MCU may check the communication with the IC by using the SPI Check register. The MCU sends the command and the response
during the next SPI transaction will be 0x123456. The SPI Check command does not return Fault Status or INTflg bit, thus interrupts will
not be cleared.
Table 13. SPI Check Command
Register Address
R
SPI Data Bits [23 - 0]
[31-25]
[24]
bits [23 - 16]
0000_000
0
0000_0000
bits [15 - 8]
0000_0000
bits [7 - 0]
0000_0000
MISO Return Word
7.10.2
0x00123456
Device Configuration Register
The device has various configuration settings that are global in nature. The configuration settings are as follows:
• When the 33978 is in the Over Voltage region, a Logic [0] on the VBATP OV bit, will limit the wetting current on all input channels to
2 mA and the 33978 will not be able to enter into the Low Power Mode. A Logic [1] will allow the device to operate normally even on
the Over Voltage region. The OV flag will be set when the device enters in the OV region, regardless the value of the VBATP OV bit.
• WAKE_B can be used to enable an external power supply regulator to supply the VDDQ voltage rail. When the WAKE_B VDDQ check
bit is a Logic [0], the WAKE_B pin is expected to be pulled-up internally or externally to VDDQ and VDDQ is expected to go low,
therefore the 33978 does not wake-up on the falling edge of WAKE_B. A Logic [1], assumes the user is using an external pull-up to
VBATP or VDDQ (when VDDQ is not expected to be off) and the IC wakes up on a falling edge of WAKE_B.
• INT_B out is used to select how the INT_B pin operates when an interrupt occurs. The IC is able to pulse low [1] or latch low [0].
• Aconfig[1-0] is used to determine the method of selecting the AMUX output, either a SPI command or using a hardwired setup using
SG[3-1].
• Inputs SP0-7 may be programmable for switch-to-battery or switch-to-ground. These inputs types are defined using the settings
command. To set a SPn input for switch-to-battery, a logic [1] for the appropriate bit must be set. To set a SPn input for switch-toground, a logic [0] for the appropriate bit must be set. The MCU may change or update the programmable switch register via software
at any time in Normal mode. Regardless of the setting, when the SPn input switch is closed a logic [1] is placed in the serial output
response register.
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
33
Table 14. Device Configuration Register
Register Address
R/W
[31-25]
[24]
0000_001
0/1
SPI Data Bits [23 - 0]
bit 23
bit 22
bit 21
bit 20
bit 19
bit 18
bit 17
bit 16
Unused
0
0
0
0
0
0
0
0
bit 15
bit 14
bit 13
bit 12
bit 11
bit 10
bit 9
bit 8
SBPOLL
TIME
VBATP OV
disable
WAKE_B
VDDQ Check
INT_B out
Aconfig1
Aconfig0
Unused
0
0
0
0
1
0
0
0
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
SP7
SP6
SP5
SP4
SP3
SP2
SP1
1
1
1
1
1
1
1
MISO Return Word
bit [23]
bit [22]
bits [21 - 0]
0000_001[R/W]
FAULT
STATUS
INTflg
Register Data
Default on POR
SP0
1
Table 15. Device Configuration Bits Definition
Bit
Functions
Default Value
Description
23-14
Unused
0
Unused
13
SBPOLLTIME
0
Select the polling time for SP channels configured as SB.
• A logic [0] set the active polling timer to 1ms,
• A logic [1] sets the active polling timer to 55 s.
12
VBATP OV
Disable
0
VBATP Overvoltage protection
• 0 - Enabled
• 1 - Disable
11
WAKE_B
VDDQ Check
1
Enable/Disable WAKE_B to wake-up the device on falling edge when VDDQ is not present.
• 0 - WAKE_B is pulled up to VDDQ (internally and/or externally). WAKE_B is ignored while in LPM if VDDQ
is low.
• 1 - WAKE_B is externally pulled up to VBATP or VDDQ and wakes upon a falling edge of the WAKE_B pin
regardless of the VDDQ status.(VDDQ is not expected to go low)
10
Int_B_Out
0
Interrupt pin behavior
• 0 - INT pin stays low when interrupt occurs
• 1 - INT pin pulse low and return high
Configure the AMUX output control method
• 00 - SPI (default)
• 01 - SPI
• 10 - HW 2bit
• 11 - HW 3bit
Refer to section 7.8, “AMUX Functional Block" for details on 2 and 3 bit hardwire configuration.
9-8
Aconfig(1-0)
00
7-0
SP7 - SP0
1111_1111
Configure the SP pin as Switch to Battery (SB) or Switch to ground (SG)
• 0 - Switch to Ground
• 1 - Switch to Battery
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
34
7.10.3
Tri-state SP Register
The tri-state command is use to set the input nodes as high-impedance (Table 16). By setting the tri-state register bit to logic [1], the input
is high-impedance regardless of the Wetting current setting. The configurable comparator (4.0 V default) on each input remains active.
The MCU may change or update the tri-state register via software at any time in Normal mode. The tri-state register defaults to 1 (inputs
are tri-stated). Any inputs in tri-state is still polled in LPM but the current source is not active during this time. The determination of change
of state occurs at the end of the tACTIVEPOLL and the wake-up decision is made.
Table 16. Tri-State SP Register
Register Address
R/W
[31-25]
[24]
0000_010
0/1
SPI Data Bits [23 - 0]
bit 23
bit 22
bit 21
bit 20
bit 19
bit 18
bit 17
bit 16
Unused
0
0
0
0
0
0
0
0
bit 15
bit 14
bit 13
bit 12
bit 11
bit 10
bit 9
bit 8
Unused
0
0
0
0
0
0
0
0
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
SP7
SP6
SP5
SP4
SP3
SP2
SP1
SP0
1
1
1
1
1
1
1
1
MISO Return Word
bit [23]
bit [22]
bits [21 - 0]
0000_010[R/W]
FAULT
STATUS
INTflg
Register Data
Default on POR
7.10.4
Tri-state SG Register
The tri-state command is used to set the input nodes as high-impedance (Table 17). By setting the tri-state register bit to logic [1], the
input is high-impedance regardless of the Wetting command setting. The configurable comparator (4.0 V default) on each input remains
active. The MCU may change or update the tri-state register via software at any time in Normal mode. The tri-state register defaults to 1
(inputs are tri-stated. Any inputs in tri-state is still polled in LPM but the current source is not active during this time. The determination of
change of state occurs at the end of the tACTIVEPOLL and the wake-up decision is made.
Table 17. Tri-State SG Register
Register Address
R/W
[31-25]
[24]
0000_011
0/1
SPI Data Bits [23 - 0]
bit 23
bit 22
bit 21
bit 20
bit 19
bit 18
bit 17
bit 16
Unused
0
0
0
0
0
0
0
0
bit 15
bit 14
bit 13
bit 12
bit 11
bit 10
bit 9
bit 8
SG13
SG12
SG11
SG10
SG9
SG8
Unused
0
0
1
1
1
1
1
1
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
SG7
SG6
SG5
SG4
SG3
SG2
SG1
SG0
1
1
1
1
1
1
1
1
MISO Return Word
bit [23]
bit [22]
bits [21 - 0]
0000_011[R/W]
FAULT
STATUS
INTflg
Register Data
Default on POR
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
35
7.10.5
Wetting Current Level SP Register
The IC contains configurable wetting currents (Default = 16 mA). Three bits are used to control each individual input pin with the values
set in Table 18. The MCU may change or update the wetting current register via software at any time in Normal mode.
Table 18. Wetting Current Level SP Register
Register Address
R/W
[31-25]
[24]
bit [23 - 21]
bit [20 - 18]
bit [17 - 16]
0000_100
0/1
SP7 [2-0]
SP6[2-0]
SP5[2-1]
110
110
11
Default on POR
SPI Data Bits [23 - 0]
bit [15]
bit [14 - 12]
bit [11 - 9]
bit [8]
SP5[0]
SP4 [2-0]
SP3[2-0]
SP2[2]
0
110
110
1
bit [7 - 6]
bit [5 - 3]
bit [2 - 0]
SP2[1-0]
SP1[2-0]
SP0[2-0]
10
110
110
MISO Return Word
bits [23 - 0]
0000_100[R/W]
Register Data
See Table 21 for the selectable Wetting Current level values for both SPx and SGx pins.
7.10.6
Wetting Current Level SG Register 0
The IC contains configurable wetting currents (Default = 16 mA). Three bits are used to control each individual input pin with the values
set in Table 19. The MCU may change or update the wetting current register via software at any time in Normal mode.
Table 19. Wetting Current Level SG Register 0
Register Address
R/W
[31-25]
[24]
bit [23 - 21]
bit [20 - 18]
bit [17 - 16]
0000_101
0/1
SG7 [2-0]
SG6[2-0]
SG5[2-1]
110
110
11
Default on POR
SPI Data Bits [23 - 0]
bit [15]
bit [14 - 12]
bit [11 - 9]
bit [8]
SG5[0]
SG4 [2-0]
SG3[2-0]
SG2[2]
0
110
110
1
bit [7 - 6]
bit [5 - 3]
bit [2 - 0]
SG2[1-0]
SG1[2-0]
SG0[2-0]
10
110
110
MISO Return Word
bits [23 - 0]
0000_101[R/W]
Register Data
See Table 21 for the selectable Wetting Current level values for both SPx and SGx pins.
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
36
7.10.7
Wetting Current Level SG Register 1
The IC contains configurable wetting currents (Default = 16 mA). Three bits are used to control each individual input pin with the values
set in Table 20. The MCU may change or update the wetting current register via software at any time in Normal mode.
Table 20. Wetting Current Level SG Register 1
Register Address
R/W
[31-25]
[24]
0000_110
0/1
Default on POR
SPI Data Bits [23 - 0]
bit [23 - 21]
bit [20 - 18]
bit [17 - 16]
Unused
SG13[2-1]
0
11
bit [15]
bit [14 - 12]
bit [11 - 9]
bit [8]
SG13[0]
SG12 [2-0]
SG11[2-0]
SG10[2]
0
110
110
1
bit [7 - 6]
bit [5 - 3]
bit [2 - 0]
SG10[1-0]
SG9[2-0]
SG8[2-0]
10
110
110
MISO Return Word
bits [23 - 0]
0000_110[R/W]
Register Data
See Table 21 for the selectable Wetting Current level values for both SPx and SGx pins.
Table 21. SPx/SGx Selectable Wetting Current Levels
SPx/SGx[2-0]
Wetting Current Level
bit 2
bit 1
bit 0
0
0
0
2.0 mA
0
0
1
6.0 mA
0
1
0
8.0 mA
0
1
1
10 mA
1
0
0
12 mA
1
0
1
14 mA
1
1
0
16 mA
1
1
1
20 mA
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
37
7.10.8
Continuous Wetting Current SP Register
Each switch input has a designated 20 ms timer. The timer starts when the specific switch input crosses the comparator threshold. When
the 20 ms timer expires, the contact current is reduced from the configured wetting current (e.g. 16 mA) to the Sustain current. The wetting
current is defined to be an elevated level that reduces to the lower sustain current level after the timer has expired. With multiple wetting
current timers disabled, power dissipation for the IC must be considered.
The MCU may change or update the continuos wetting current register via software at any time in Normal mode. This allows the MCU to
control the amount of time wetting current is applied to the switch contact. Programming the continuos wetting current bit to logic [0]
operates normally with a higher wetting current followed by sustain current after 20 ms (pulsed Wetting current operation). Programming
to logic [1] enables the continuous wetting current (Table 22) and result in a full time wetting current level. The continuous wetting current
register defaults to 0 (pulse wetting current operation).
Table 22. Continuous Wetting Current SP Register
Register Address
R/W
[31-25]
[24]
0001_011
0/1
SPI Data Bits [23 - 0]
bit 23
bit 22
bit 21
bit 20
bit 19
bit 18
bit 17
bit 16
Unused
0
0
0
0
0
0
0
0
bit 15
bit 14
bit 13
bit 12
bit 11
bit 10
bit 9
bit 8
Unused
0
0
0
0
0
0
0
0
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
SP7
SP6
SP5
SP4
SP3
SP2
SP1
SP0
0
0
0
0
0
0
0
0
MISO Return Word
bit [23]
bit [22]
bits [21 - 0]
0001_011[R/W]
FAULT
STATUS
INTflg
Register Data
Default on POR
7.10.9
Continuous Wetting Current SG Register
Each switch input has a designated 20 ms timer. The timer starts when the specific switch input crosses the comparator threshold. When
the 20 ms timer expires, the contact current is reduced from the configured wetting current (e.g. 16 mA) to 2.0 mA. The wetting current is
defined to be at an elevated level that reduces to the lower sustain current level after the timer has expired. With multiple wetting current
timers disabled, power dissipation for the IC must be considered.
The MCU may change or update the continuous wetting current register via software at any time in Normal mode. This allows the MCU
to control the amount of time wetting current is applied to the switch contact. Programming the continuos wetting current bit to logic [0]
operates normally with a higher wetting current followed by sustain current after 20 ms (Pulse wetting current operation). Programming to
logic [1] enables the continuous wetting current (Table 23) and result in a full time wetting current level. The continuous wetting current
register defaults to 0 (pulse wetting current operation).
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
38
Table 23. Continuous Wetting Current SG Register
Register Address
R/W
[31-25]
[24]
0001_100
0/1
SPI Data Bits [23 - 0]
bit 23
bit 22
bit 21
bit 20
bit 19
bit 18
bit 17
bit 16
Unused
0
0
0
0
0
0
0
0
bit 15
bit 14
bit 13
bit 12
bit 11
bit 10
bit 9
bit 8
SG13
SG12
SG11
SG10
SG9
SG8
Unused
0
0
0
0
0
0
0
0
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
SG7
SG6
SG5
SG4
SG3
SG2
SG1
SG0
0
0
0
0
0
0
0
0
MISO Return Word
bit [23]
bit [22]
bits [21 - 0]
0001_100[R/W]
FAULT
STATUS
INTflg
Register Data
Default on POR
Switch to
Ground Closed
Switch to
Ground open
IWET
Continuous wetting
current enabled
0 ma
IWET
Continuous wetting
current disabled
ISUS=~2mA
0 ma
20 ms
Figure 22. Pulsed/Continuos Wetting Current Configuration
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
39
7.10.10 Interrupt Enable SP Register
The interrupt register defines the inputs that are allowed to Interrupt the 33978 Normal mode. Programming the interrupt bit to logic [0]
disables the specific input from generating an interrupt. Programming the interrupt bit to logic [1] enables the specific input to generate an
interrupt with switch change of state The MCU may change or update the interrupt register via software at any time in Normal mode. The
Interrupt register defaults to logic [1] (Interrupt enabled).
Table 24. Interrupt Enable SP Register
Register Address
R/W
[31-25]
[24]
0001_101
0/1
SPI Data Bits [23 - 0]
bit 23
bit 22
bit 21
bit 20
bit 19
bit 18
bit 17
bit 16
Unused
0
0
0
0
0
0
0
0
bit 15
bit 14
bit 13
bit 12
bit 11
bit 10
bit 9
bit 8
Unused
0
0
0
0
0
0
0
0
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
SP7
SP6
SP5
SP4
SP3
SP2
SP1
SP0
1
1
1
1
1
1
1
1
MISO Return Word
bit [23]
bit [22]
bits [21 - 0]
0001_101[R/W]
FAULT
STATUS
INTflg
Register Data
Default on POR
7.10.11 Interrupt Enable SG Register
The interrupt register defines the inputs that are allowed to Interrupt the 33978 Normal mode. Programming the interrupt bit to logic [0]
disables the specific input from generating an interrupt. Programming the interrupt bit to logic [1] enables the specific input to generate an
interrupt with switch change of state The MCU may change or update the interrupt register via software at any time in Normal mode. The
Interrupt register defaults to logic [1] (Interrupt enabled).
Table 25. Interrupt Enable SG Register
Register Address
R/W
[31-25]
[24]
0001_110
0/1
SPI Data Bits [23 - 0]
bit 23
bit 22
bit 21
bit 20
bit 19
bit 18
bit 17
bit 16
Unused
0
0
0
0
0
0
0
0
bit 15
bit 14
bit 13
bit 12
bit 11
bit 10
bit 9
bit 8
SG13
SG12
SG11
SG10
SG9
SG8
Unused
0
0
1
1
1
1
1
1
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
SG7
SG6
SG5
SG4
SG3
SG2
SG1
SG0
1
1
1
1
1
1
1
1
MISO Return Word
bit [23]
bit [22]
bits [21 - 0]
0001_110[R/W]
FAULT
STATUS
INTflg
Register Data
Default on POR
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
40
7.10.12 Low-power Mode Configuration
The device has various configuration settings for the Low-power mode operation. The configuration settings are as follows:
int[3-0] is used to set the interrupt timer value. With the interrupt timer set, the IC wakes up after the selected timer expires and issue an
interrupt. This register can be selected to be OFF such that the IC does not wake-up from an interrupt timer.
poll[3-0] is used to set the normal polling rate for the IC. The polling rate is the time between polling events. The current sources become
active at this time for a time of tACTIVESGPOLLING or tACTIVESBPOLLING for SG or SB channels respectively.
Table 26. Low Power Mode Configuration Register
Register Address
R/W
[31-25]
[24]
0001_111
0/1
SPI Data Bits [23 - 0]
bit 23
bit 22
bit 21
bit 20
bit 19
bit 18
bit 17
bit 16
Unused
0
0
0
0
0
0
0
0
bit 15
bit 14
bit 13
bit 12
bit 11
bit 10
bit 9
bit 8
Unused
0
0
0
0
0
0
0
0
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
int3
int2
int1
int0
poll3
poll2
poll1
poll0
0
0
0
0
1
1
1
1
MISO Return Word
bit [23]
bit [22]
bits [21 - 0]
0001_111[R/W]
FAULT
STATUS
INTflg
Register Data
Default on POR
Table 27. Low Power Mode Configuration Bits Definition
Bit
Functions
Default Value
23 - 8
Unused
0
Description
Unused
Set the Interrupt timer value
7-4
int[3-0]
0000
•
•
•
•
•
•
•
•
0000 - OFF
0001 - 6.0 ms
0010 - 12 ms
0011 - 24 ms
0100 - 48 ms
0101 - 96 ms
0110 - 192 ms
0111 - 394 ms
•
•
•
•
•
•
•
•
1000 - 4.0 ms
1001 - 8.0 ms
1010 - 16 ms
1011 - 32 ms
1100 - 64 ms
1101 - 128 ms
1110 - 256 ms
1111 - 512 ms
•
•
•
•
•
•
•
•
1000 - 32 ms
1001 - 36 ms
1010 - 40 ms
1011 - 44 ms
1100 - 52 ms
1101 - 56 ms
1110 - 60 ms
1111 - 64 ms (default)
Set the polling rate for switch detection
3-0
poll[3-0]
1111
•
•
•
•
•
•
•
•
0000 - 3.0 ms
0001 - 6.0 ms
0010 - 12 ms
0011 - 24 ms
0100 - 48 ms
0101 - 68 ms
0110 - 76 ms
0111 - 128 ms
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
41
7.10.13 Wake-up Enable Register SP
The wake-up register defines the inputs that are allowed to wake the 33978 from Low-power mode. Programming the wake-up bit to
logic [0] disables the specific input from waking the IC (Table 28). Programming the wake-up bit to logic [1] enables the specific input to
wake-up with switch change of state The MCU may change or update the wake-up register via software at any time in Normal mode. The
Wake-up register defaults to logic [1] (wake-up enabled). If all channels (SG and SB) have the Wake-up bit disabled, the device will disable
the polling timer to reduce the current consumption during Low Power mode.
Table 28. Wake-up Enable SP Register
Register Address
R/W
[31-25]
[24]
0010_000
0/1
SPI Data Bits [23 - 0]
bit 23
bit 22
bit 21
bit 20
bit 19
bit 18
bit 17
bit 16
Unused
0
0
0
0
0
0
0
0
bit 15
bit 14
bit 13
bit 12
bit 11
bit 10
bit 9
bit 8
Unused
0
0
0
0
0
0
0
0
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
SP7
SP6
SP5
SP4
SP3
SP2
SP1
SP0
1
1
1
1
1
1
1
1
MISO Return Word
bit [23]
bit [22]
bits [21 - 0]
0010_000[R/W]
FAULT
STATUS
INTflg
Register Data
Default on POR
7.10.14 Wake-up Enable Register SG
The wake-up register defines the inputs that are allowed to wake the 33978 from Low-power mode. Programming the wake-up bit to
logic [0] disables the specific input from waking the IC (Table 29). Programming the wake-up bit to logic [1] enables the specific input to
wake-up with any switch change of state The MCU may change or update the wake-up register via software at any time in Normal mode.
The Wake-up register defaults to logic [1] (wake-up enabled). If all channels (SG and SB) have the Wake-up bit disabled, the device will
disable the polling timer to reduce the current consumption during Low Power mode.
Table 29. Wake-up Enable SG Register
Register Address
R/W
[31-25]
[24]
0010_001
0/1
SPI Data Bits [23 - 0]
bit 23
bit 22
bit 21
bit 20
bit 19
bit 18
bit 17
bit 16
Unused
0
0
0
0
0
0
0
0
bit 15
bit 14
bit 13
bit 12
bit 11
bit 10
bit 9
bit 8
SG13
SG12
SG11
SG10
SG9
SG8
Unused
0
0
1
1
1
1
1
1
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
SG7
SG6
SG5
SG4
SG3
SG2
SG1
SG0
1
1
1
1
1
1
1
1
MISO Return Word
bit [23]
bit [22]
bits [21 - 0]
0010_001[R/W]
FAULT
STATUS
INTflg
Register Data
Default on POR
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
42
7.10.15 Comparator Only SP
The comparator only register allows the input comparators to be active during LPM with no polling current. In this case, the inputs can
receive a digital signal on the order of the LPM clock cycle and wake-up on a change of state. This register is intended to be used for
signals that are driven by an external chip and drive to 5.0 V.
Table 30. Comparator Only SP Register
Register Address
R/W
[31-25]
[24]
0010_010
0/1
SPI Data Bits [23 - 0]
bit 23
bit 22
bit 21
bit 20
bit 19
bit 18
bit 17
bit 16
Unused
0
0
0
0
0
0
0
0
bit 15
bit 14
bit 13
bit 12
bit 11
bit 10
bit 9
bit 8
Unused
0
0
0
0
0
0
0
0
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
SP7
SP6
SP5
SP4
SP3
SP2
SP1
SP0
0
0
0
0
0
0
0
0
MISO Return Word
bit [23]
bit [22]
bits [21 - 0]
0010_010[R/W]
FAULT
STATUS
INTflg
Register Data
Default on POR
7.10.16 Comparator Only SG
The comparator only register allows the input comparators to be active during LPM with no polling current. In this case, the inputs can
receive a digital signal on the order of the LPM clock cycle and wake-up on a change of state. This register is intended to be used for
signals that are driven by an external chip and drive to 5.0 V.
Table 31. Comparator Only SG Register
Register Address
R/W
[31-25]
[24]
0010_011
0/1
SPI Data Bits [23 - 0]
bit 23
bit 22
bit 21
bit 20
bit 19
bit 18
bit 17
bit 16
Unused
0
0
0
0
0
0
0
0
bit 15
bit 14
bit 13
bit 12
bit 11
bit 10
bit 9
bit 8
SG13
SG12
SG11
SG10
SG9
SG8
Unused
0
0
0
0
0
0
0
0
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
SG7
SG6
SG5
SG4
SG3
SG2
SG1
SG0
0
0
0
0
0
0
0
0
MISO Return Word
bit [23]
bit [22]
bits [21 - 0]
0010_011[R/W]
FAULT
STATUS
INTflg
Register Data
Default on POR
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
43
7.10.17 LPM Voltage Threshold SP Configuration
The 33978 is able to use different voltage thresholds to wake-up from LPM. When configured as SG, a Logic [0] means the input will use
the LPM delta voltage threshold to determine the state of the switch. A Logic [1] means the input will use the Normal threshold (VICTHR)
to determine the state of the switch. When configured as an SB, it only uses the 4.0V threshold regardless the status of the LPM voltage
threshold bit. The user must ensure that the correct current level is set to allow the crossing of the normal mode threshold (typ 4.0v)
Table 32. LPM Voltage Threshold Configuration SP Register
Register Address
R/W
[31-25]
[24]
0010_100
0/1
SPI Data Bits [23 - 0]
bit 23
bit 22
bit 21
bit 20
bit 19
bit 18
bit 17
bit 16
Unused
0
0
0
0
0
0
0
0
bit 15
bit 14
bit 13
bit 12
bit 11
bit 10
bit 9
bit 8
Unused
0
0
0
0
0
0
0
0
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
SP7
SP6
SP5
SP4
SP3
SP2
SP1
SP0
0
0
0
0
0
0
0
0
MISO Return Word
bit [23]
bit [22]
bits [21 - 0]
0010_100[R/W]
FAULT
STATUS
INTflg
Register Data
Default on POR
7.10.18 LPM Voltage threshold SG Configuration
This means the input uses the LPM delta voltage threshold to determine the state of the switch. A Logic [1] means the input uses the
Normal threshold to determine the state of the switch. The user must ensure that the correct current level is set to allow the crossing of
the normal mode threshold (typ 4.0 V)
Table 33. LPM Voltage Threshold Configuration SG Register
Register Address
R/W
[31-25]
[24]
0010_101
0/1
SPI Data Bits [23 - 0]
bit 23
bit 22
bit 21
bit 20
bit 19
bit 18
bit 17
bit 16
Unused
0
0
0
0
0
0
0
0
bit 15
bit 14
bit 13
bit 12
bit 11
bit 10
bit 9
bit 8
SG13
SG12
SG11
SG10
SG9
SG8
Unused
0
0
0
0
0
0
0
0
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
SG7
SG6
SG5
SG4
SG3
SG2
SG1
SG0
0
0
0
0
0
0
0
0
MISO Return Word
bit [23]
bit [22]
bits [21 - 0]
0010_101[R/W]
FAULT
STATUS
INTflg
Register Data
Default on POR
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
44
7.10.19 Polling Current SP Configuration
The normal polling current for LPM is 2.2 mA for SB channels and 1.0 mA for SG channels, A logic [0] will select the normal polling current
for each individual channel. The user may choose to select the IWET current value as defined in the wetting current level registers by writing
a Logic [1] on this bit; this will result in higher LPM currents but may be used in cases when a higher polling current is needed.
Table 34. Polling Current Configuration SP Register
Register Address
R/W
[31-25]
[24]
0010_110
0/1
SPI Data Bits [23 - 0]
bit 23
bit 22
bit 21
bit 20
bit 19
bit 18
bit 17
bit 16
Unused
0
0
0
0
0
0
0
0
bit 15
bit 14
bit 13
bit 12
bit 11
bit 10
bit 9
bit 8
Unused
0
0
0
0
0
0
0
0
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
SP7
SP6
SP5
SP4
SP3
SP2
SP1
SP0
0
0
0
0
0
0
0
0
MISO Return Word
bit [23]
bit [22]
bits [21 - 0]
0010_110[R/W]
FAULT
STATUS
INTflg
Register Data
Default on POR
7.10.20 Polling Current SG Configuration
A Logic [0] will select the normal polling current for LPM =1.0 mA. The user may choose to select the IWET current value as defined in the
wetting current registers for LPM by writing a Logic [1] in this bit; this will result in higher LPM currents but may be used in cases when a
higher polling current is needed.
Table 35. Polling Current Configuration SG Register
Register Address
R/W
[31-25]
[24]
0010_111
0/1
SPI Data Bits [23 - 0]
bit 23
bit 22
bit 21
bit 20
bit 19
bit 18
bit 17
bit 16
Unused
0
0
0
0
0
0
0
0
bit 15
bit 14
bit 13
bit 12
bit 11
bit 10
bit 9
bit 8
SG13
SG12
SG11
SG10
SG9
SG8
Unused
0
0
0
0
0
0
0
0
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
SG7
SG6
SG5
SG4
SG3
SG2
SG1
SG0
0
0
0
0
0
0
0
0
MISO Return Word
bit [23]
bit [22]
bits [21 - 0]
0010_111[R/W]
FAULT
STATUS
INTflg
Register Data
Default on POR
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
45
7.10.21 Slow Polling SP
The normal polling rate is defined in the Low-power mode configuration register. If the user is able to poll at a slower rate (4x) the LPM
current level decreases significantly. Setting the bit to [0] results in the input polling at the normal rate as selected. Setting the bit to [1]
results in the input being polled at a slower frequency at 4x the normal rate.
Table 36. Slow Polling SP Register
Register Address
R/W
[31-25]
[24]
0011_000
0/1
SPI Data Bits [23 - 0]
bit 23
bit 22
bit 21
bit 20
bit 19
bit 18
bit 17
bit 16
Unused
0
0
0
0
0
0
0
0
bit 15
bit 14
bit 13
bit 12
bit 11
bit 10
bit 9
bit 8
Unused
0
0
0
0
0
0
0
0
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
SP7
SP6
SP5
SP4
SP3
SP2
SP1
SP0
0
0
0
0
0
0
0
0
MISO Return Word
bit [23]
bit [22]
bits [21 - 0]
0011_000[R/W]
FAULT
STATUS
INTflg
Register Data
Default on POR
7.10.22 Slow Polling SG
The normal polling rate is defined in the Low-power mode configuration register. If the user is able to poll at a slower rate (4x) the LPM
current level decreases significantly. Setting the bit to [0] results in the input polling at the normal rate as selected. Setting the bit to [1]
results in the input being polled at a slower frequency at 4x the normal rate.
Table 37. Slow Polling SG Register
Register Address
R/W
[31-25]
[24]
0011_001
0/1
SPI Data Bits [23 - 0]
bit 23
bit 22
bit 21
bit 20
bit 19
bit 18
bit 17
bit 16
Unused
0
0
0
0
0
0
0
0
bit 15
bit 14
bit 13
bit 12
bit 11
bit 10
bit 9
bit 8
SG13
SG12
SG11
SG10
SG9
SG8
Unused
0
0
0
0
0
0
0
0
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
SG7
SG6
SG5
SG4
SG3
SG2
SG1
SG0
0
0
0
0
0
0
0
0
MISO Return Word
bit [23]
bit [22]
bits [21 - 0]
0011_001[R/W]
FAULT
STATUS
INTflg
Register Data
Default on POR
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
46
7.10.23 Wake-up Debounce SP
The IC is able to extend the time that the active polling takes place to ensure that a true change of state has occurred in LPM and reduce
the chance that noise has impacted the measurement. If this bit is [0], the IC uses a voltage difference technique to determine if a switch
has changed sate. If this bit is set [1], the IC debounces the measurement by continuing to source the LPM polling current for an additional
1.2 ms and take the measurement based on the final voltage level. This helps to ensure that the switch is detected correctly in noisily
systems.
Table 38. Wake-up Debounce SP Register
Register Address
R/W
[31-25]
[24]
0011_010
0/1
SPI Data Bits [23 - 0]
bit 23
bit 22
bit 21
bit 20
bit 19
bit 18
bit 17
bit 16
Unused
0
0
0
0
0
0
0
0
bit 15
bit 14
bit 13
bit 12
bit 11
bit 10
bit 9
bit 8
Unused
0
0
0
0
0
0
0
0
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
SP7
SP6
SP5
SP4
SP3
SP2
SP1
SP0
0
0
0
0
0
0
0
0
MISO Return Word
bit [23]
bit [22]
bits [21 - 0]
0011_010[R/W]
FAULT
STATUS
INTflg
Register Data
Default on POR
7.10.24 Wake-up Debounce SG
The IC is able to extend the time that the active polling takes place to ensure that a true change of state has occurred in LPM and reduce
the chance that noise has impacted the measurement. If this bit is [0], the IC uses a voltage difference technique to determine if a switch
has changed sate. If this bit is set [1], the IC debounces the measurement by continuing to source the LPM polling current for an additional
1.2 ms and take the measurement based on the final voltage level. This helps to ensure that the switch is detected correctly in noisily
systems.
Table 39. Slow Polling SG Register
Register Address
R/W
[31-25]
[24]
0011_011
0/1
SPI Data Bits [23 - 0]
bit 23
bit 22
bit 21
bit 20
bit 19
bit 18
bit 17
bit 16
Unused
0
0
0
0
0
0
0
0
bit 15
bit 14
bit 13
bit 12
bit 11
bit 10
bit 9
bit 8
SG13
SG12
SG11
SG10
SG9
SG8
Unused
0
0
0
0
0
0
0
0
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
SG7
SG6
SG5
SG4
SG3
SG2
SG1
SG0
0
0
0
0
0
0
0
0
MISO Return Word
bit [23]
bit [22]
bits [21 - 0]
0011_011[R/W]
FAULT
STATUS
INTflg
Register Data
Default on POR
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
47
7.10.25 Enter Low-power Mode
Low-power mode (LPM) is used to reduce system quiescent currents. Low-power mode may be entered only by sending the Low-power
command. When returning to Normal mode, all register settings is maintained.
The Enter Low-power mode register is write only and has the effect of going to LPM and beginning operation as selected (polling, interrupt
timer). When returning form Low-power mode, the first SPI transaction will return the Fault Status and the intflg bit set to high, as well as
the actual status of the Input pins.
Table 40. Enter Low Power Mode Command
Register Address
W
SPI Data Bits [23 - 0]
[31-25]
[24]
bits [23 - 16]
0011_100
1
0000_0000
bits [15 - 8]
0000_0000
bits [7 - 0]
0000_0000
MISO Return Word
-
7.10.26 AMUX Control Register
The analog voltage on switch inputs may be read by the MCU using the analog command (Table 41). Internal to the33978 is a 24-to-1
analog multiplexer. The voltage present on the selected input pin is buffered and made available on the AMUX output pin. The AMUX
output pin is clamped to a maximum of VDDQ volts regardless of the higher voltages present on the input pin. After an input has been
selected as the analog, the corresponding bit in the next MISO data stream is logic [0].
Setting the current to wetting current (configurable) may be useful for reading sensor inputs. The MCU may change or update the analog
select register via software at any time in Normal mode. The analog select defaults to no input.
Table 41. Slow Polling SG Register
Register Address
R/W
[31-25]
[24]
0011_101
0/1
SPI Data Bits [23 - 0]
bit 23
bit 22
bit 21
bit 20
bit 19
bit 18
bit 17
bit 16
Unused
0
0
0
0
0
0
0
0
bit 15
bit 14
bit 13
bit 12
bit 11
bit 10
bit 9
bit 8
Unused
0
0
0
0
0
0
0
0
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
Unused
asett0
0
0
0
0
0
MISO Return Word
bit [23]
bit [22]
bits [21 - 0]
0011_101[R/W]
FAULT
STATUS
INTflg
Register Data
Default on POR
asel[5-0]
0
0
0
Table 42. AMUX Current Select
asett[0]
Zsource
0
hi Z (default)
1
IWET
33978
Analog Integrated Circuit Device Data
Freescale Semiconductor
48
Table 43. AMUX channel select
asel 5
asel 4
asel3
asel 2
asel 1
asel 0
Analog Channel Select
0
0
0
0
0
0
No Input Selected
0
0
0
0
0
1
SG0
0
0
0
0
1
0
SG1
0
0
0
0
1
1
SG2
0
0
0
1
0
0
SG3
0
0
0
1
0
1
SG4
0
0
0
1
1
0
SG5
0
0
0
1
1
1
SG6
0
0
1
0
0
0
SG7
0
0
1
0
0
1
SG8
0
0
1
0
1
0
SG9
0
0
1
0
1
1
SG10
0
0
1
1
0
0
SG11
0
0
1
1
0
1
SG12
0
0
1
1
1
0
SG13
0
0
1
1
1
1
SP0
0
1
0
0
0
0
SP1
0
1
0
0
0
1
SP2
0
1
0
0
1
0
SP3
0
1
0
0
1
1
SP4
0
1
0
1
0
0
SP5
0
1
0
1
0
1
SP6
0
1
0
1
1
0
SP7
0
1
0
1
1
1
Temp Diode
0
1
1
0
0
0
Battery Sense
7.10.27 Read Switch Status
The Read switch status register is used to determine the state of each of the inputs and is read only. All of the inputs (SGn and SPn) are
returned after the next command is sent. A Logic [1] means the switch is closed while a Logic [0] is an open switch.
Included in the status register are two more bits, the Fault Status bit and intflg bit. The Fault Status bit is a combination of the extended
status bits and the wetting current fault bits. If any of these bits are set, the Fault Status bit is set. The intflg bit is set when an interrupt
occurs on this device.
After POR, both the Fault Status bit and the intflg bit are set high to indicate an interrupt due to a POR occurred. The intflg bit will be
cleared upon reading the Read Switch Status register, and the Fault Status bit will remain high until the Fault status register is read and
thus the POR fault bit and all other fault flags are cleared.
The Fault Status and Intflg bits are semi-global flags, if a fault or an interrupt occurs, these bit will be returned after writing or reading any
command, except for the SPICheck and the Wetting Current configuration registers, which use those bits to set/display the device
configuration.
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Table 44. Read Switch Status Command
Register Address
R
SPI Data Bits [23 - 0]
[31-25]
[24]
bit 23
bit 22
bit 21
bit 20
bit 19
bit 18
bit 17
bit 16
0011_111
0
FAULT
STATUS
INTflg
SP7
SP6
SP5
SP4
SP3
SP2
1
1
X
X
X
X
X
X
bit 15
bit 14
bit 13
bit 12
bit 11
bit 10
bit 9
bit 8
SP1
SP0
SG13
SG12
SG11
SG10
SG9
SG8
X
X
X
X
X
X
X
X
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
SG7
SG6
SG5
SG4
SG3
SG2
SG1
SG0
X
X
X
X
X
X
X
X
MISO Return Word
bit [23]
bit [22]
bits [21-14]
bits [13-0]
0011_1110
FAULT
STATUS
INTflg
SP7 -SP0 Switch Status
SG13 - SG0 Switch Status
Default After POR
The fault/status diagnostic capability consists of one internal 24 bit register. The content of the fault/status register is shown in Table 45.
Bits 0 – 21 shows the status of each input where logic [1] is a closed switch and logic [0] is an open switch. In addition to input status
information, Fault status such as die over-temp, Hash fault, SPI errors, as well as interrupts are reported.
A SPI read cycle is initiated by a CS_B logic ‘1’ to ‘0’ transition, followed by 32 SCLK cycles to shift the fault / status registers out the MISO
pin. The INT_B pin is cleared 1.0 ms after the falling edge of CS_B. The fault is immediately set again if the fault condition is still present.
The Fault Status bit sets any time a Fault occurs, and the Fault register (Table 46) must be read in order to clear the Fault status flag.
The intflg bit sets any time an interrupt event occurs (change of state on switch, any fault status bit gets set). Any SPI message that will
return intflg bit will clear this flag (even if the event is still occurring, for example an overtemp, will cause an interrupt. The interrupt can be
cleared but the chip will not interrupt again based on the overtemp until that fault has gone away).
SG0
SG1
SG2
SG3
SG4
SG5
SG6
SG7
SG8
SG9
SG10
SG11
SG12
SG13
SP0
SP1
SP2
SP3
SP4
SP5
SP6
SP7
INTflg
MISO
Response
Sends
Fault Status
Table 45. MISO Output Register Definition
Bit 23 : Fault Status:
• 0 = No Fault
• 1 = Indicates a fault has occurred and should be viewed in the fault status register.
Bit 22 : Intflg:
• 0 = No Change of state
• 1 = Change of state detected.
Bit 21 – 0 : SPx /SGx input status:
• 0 = Open switch;
• 1 =Closed switch
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7.10.28 Fault Status Register
To read the fault status bits the user should first sent a message to the IC with the fault status register address followed by any given
second command. The MISO response from the second command will contain the fault flags information.
Table 46. Fault Status Register
Register Address
R
SPI Data Bits [23 - 0]
[31-25]
[24]
bit 23
bit 22
0100_001
0
Unused
INTflg
0
1
0
0
bit 15
bit 14
bit 13
bit 12
bit 21
bit 20
bit 19
bit 18
bit 17
bit 16
0
0
0
0
bit 11
bit 10
bit 9
bit 8
SPI error
Hash Fault
Unused
Unused
Unused
0
0
0
0
0
X
X
0
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
UV
OV
TempFlag
OT
INT_B Wake
WAKE_B
Wake
SPI Wake
POR
X
X
X
X
X
X
X
X
MISO Return Word
bit [23]
bit [22]
bits [21-0]
0100_0010
FAULT
STATUS
INTflg
FAULT/FLAG BITS
Default After POR
Table 47. MISO Response for Fault Status Command
Bit
Functions
Default Value
Description
23
Unused
0
Unused
22
INTflg
X
Reports that an Interrupt has occurred, user should read the status register to determine cause.
• Set: Various (SGx change of state, SPx change of state, Extended status bits).
• Reset: Clear of fault or read of Status register
21-11
Unused
0
Unused
10
SPI error
X
Any SPI error generates a bit (Wrong address, incorrect modulo).
• Set: SPI message error.
• Reset: Read fault status register and no SPI errors.
9
Hash Fault
X
SPI register and hash mismatch.
• Set: Mismatch between SPI registers and hash.
• Reset: No mismatch and SPI flag read.
8
Unused
0
Unused
7
UV
X
Reports that low VBATP voltage was in undervoltage range
• Set: Voltage drops below UV level.
• Reset: VBATP rises above UV level and flag read (SPI)
6
OV
X
Report that the voltage on VBATP was higher than OV threshold
• Set: Voltage at VBATP rises above overvoltage threshold.
• Reset: Overvoltage condition is over and flag read (SPI)
5
Temp Flag
X
Temperature warning to note elevated IC temperature
• Set: tLIM warning threshold is passed.
• Reset: Temperature drops below thermal warning threshold + hysteresis and flag read (SPI)
4
OT
X
Tlim event occurred on the IC
• Set: Tlim warning threshold is passed.
• Reset: Temperature drops below thermal warning threshold + hysteresis and flag read (SPI)
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Table 47. MISO Response for Fault Status Command (continued)
3
INT_B Wake
X
Part awakens via an external INT_B falling edge
• Set: INT_B Wakes the part from LPM (external falling edge)
• Reset: flag read (SPI).
2
WAKE_B Wake
X
Part awakens via an external WAKE_B falling edge
• Set: External WAKE_B falling edge seen
• Reset: flag read (SPI).
1
SPI Wake
X
Part awaken via a SPI message
• Set: SPI message wakes the IC from LPM
• Reset: flag read (SPI).
0
POR
X
Reports a POR event occurred.
• Set: Voltage at VBATP pin dropped below VBATP(POR) voltage
• Reset: flag read (SPI)
7.10.29 Interrupt Request
The MCU may request an Interrupt pulse of duration 100 s by sending the Interrupt request command. After an Interrupt request
commands, the 33978 will return the Interrupt request command word, as well as the Fault status and INTflg bits set if a fault/interrupt
event occurred. Sending an interrupt request command does not set the INTflg bit itself.
Table 48. Interrupt Request Command
Register Address
W
SPI Data Bits [23 - 0]
[31-25]
[24]
bits [23 - 16]
0100_011
1
0000_0000
bits [15 - 8]
0000_0000
bits [7 - 0]
0000_0000
MISO Return Word
bit [23]
bit [22]
bits [21-0]
0100_0111
FAULT
STATUS
INTflg
0
7.10.30 Reset Register
Writing to this register causes all of the SPI registers to reset.
Table 49. Reset Command
Register Address
W
SPI Data Bits [23 - 0]
[31-25]
[24]
bits [23 - 16]
0100_100
1
0000_0000
bits [15 - 8]
0000_0000
bits [7 - 0]
0000_0000
MISO Return Word
bit [23]
bit [22]
bits [21-0]
0011_1110
FAULT
STATUS
INTflg
Switch Status
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8
Typical Applications
8.1
Application Diagram
Figure 23. Typical Application Diagram
8.2
Bill of Materials
Table 50. Bill of Materials
Item
Quantity
Reference
Value
Description
1
24
C1, C2, C3, C4, C5, C6, C7, C8, C9, C10,
C11, C12, C13, C14, C15, C16, C17, C18,
C19, C20, C21, C22, C25, C27
0.1F
CAP CER 0.1 uF 100 V X7R 10% 0603
2
2
C23,C24
1.0 nF
CAP CER 1000 PF 100 V 10% X7R 0603
3
1
C26
100 F
CAP ALEL 100 F 50 V 20% -- SMD
4
1
D1
-
5
22
R1, R2, R3, R4, R5, R6, R7, R8, R9, R10,
R11, R12, R13, R14, R15, R16, R17, R18,
R19, R20, R21, R22
100 
RES MF 100  0.5 W 1% 0805
6
1
R23
10 k
RES MF 10 k 0.5 W 5% 0805 (Optional)
7
1
R25
10 k
RES MF 10 k 0.5 W 5% 0805
8
1
R24
1.0 k
RES MF 1 k 0.5 W 5% 0805
9
1
U1
MC33978
DIODE RECT 3.0 A 50 V AEC-Q101 SMB
IC MULTIPLE DETECTION SWITCH INTERFACE SOIC32
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8.3
Abnormal Operation
The 33978 could be subject to various conditions considered abnormal as defined within this section.
8.3.1
Reverse Battery
This device with applicable external components will not be damaged by exposure to reverse battery conditions of -14 V. This test is
performed for a period of one minute at 25 °C. In addition, this negative voltage condition does not force any of the logic level I/O pins to
a negative voltage less than -0.6 V at 10 mA or to a positive voltage greater the 5.0 V. This insures protection of the digital device
interfacing with this device.
8.3.2
Ground Offset
The applicable driver outputs and/or current sense inputs are capable of operation with a ground offset of 1.0 V. The device will not be
damaged by exposure to this condition and will maintain specified functionality.
8.3.3
Shorts To Ground
All I/Os of the device that are available at the module connector are protected against shorts to ground with maximum ground offset
considered (i.e. -1.0 V referenced to device ground or other application specific value). The device will not be damaged by this condition.
8.3.4
Shorts To Battery
All I/Os of the device that are available at the module connector are protected against a short to battery (voltage value is application
dependent, there may be cases where short to jump start or load dump voltage values are required). The device will not be damaged by
this condition.
8.3.5
Unpowered Shorts To Battery
All I/Os of the device that are available at the module connector are protected against unpowered (battery to the module is open) shorts
to battery per application specifics. The device will not be damaged by this condition, will not enable any outputs nor backfeed onto the
power rails (i.e, VBATP, VDDQ) or the digital I/O pins.
8.3.6
Loss of Module Ground
The definition of a loss of ground condition at the device level is that all pins of the IC detects very low-impedance to battery. The
nomenclature is suited to a test environment. In the application, a loss of ground condition results in all I/O pins floating to battery voltage,
while all externally referenced I/O pins are at worst case pulled to ground. All applicable driver outputs and current sense inputs are
protected against excessive leakage current due to loads that are referenced to an external ground (i.e, high-side drivers).
8.3.7
Loss of Module Battery
The loss of battery condition at the parts level is that the power input pins of the IC see infinite impedance to the battery supply voltage
(depending upon the application) but there is some undefined impedance looking from these pins to ground. All applicable driver outputs
and current sense inputs are protected against excessive leakage current due to loads that are referenced to an external battery
connection (i.e., low-side drivers).
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9
Packaging
9.1
Package Mechanical Dimensions
Package dimensions are provided in package drawings. To find the most current package outline drawing, go to www.freescale.com and
perform a keyword search for the drawing’s document number.
Table 51. Packaging Information
Package
Suffix
Package Outline Drawing Number
32-Pin SOICW-EP
EK
98ASA10556D
32-Pin QFN (WF-type)
ES
98ASA00656D
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10
Reference Section
Table 52. 33978 Reference Documents
Reference
Description
CDF-AEC-Q100
Stress Test Qualification For Automotive Grade Integrated Circuits
Q-1000
Qualification Specification for Integrated Circuits
SQ-1001
Specification Conformance
ISO 7637
Electrical Disturbances from Conduction and Coupling
ISO 61000
Electromagnetic Compatibility
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11
Revision History
REVISION
DATE
DESCRIPTION OF CHANGES
1.0
3/2014
• Initial release
2.0
3/2014
• Removed Z from part numbers PCZ33978EK and PCZ33978ES in the Orderable Part Variations table
• Major formatting and information arrangement
• Updated Figure 1, 33978 Simplified Application Diagram, removed CS_B pull-up resistor, not needed.
• Added Industrial Part numbers MC34978EK and MC34978ES to Table 1
• Table 3 Clarified Switch Input Range specification (not a differential voltage between inputs and VBATP)
• Table 3 Reduced Human Body Model (HBM) (VBATP versus GND) to 2500 V
• Table 3 VESD6-2 Series resistor corrected to 50  Added missing CZAP and RZAP conditions
• Table 4 Updated Thermal Resistance specification
• Added Figure 10, Functional Block Diagram
• Added Figure 11, Battery Voltage Range
• Added Figure 5, Glitch Filter and Interrupt Delay timers and Figure 6, Interrupt Pulse Timer
• Updated POR minimum specification to 2.7 V (previous 2.9 V)
• Updated VBATP Normal mode maximum supply current to 12 mA (previous 8.0 mA)
• Updated VDDQ undervoltage threshold maximum to 2.8 V (previous 2.7 V)
• Updated sustain current at low battery to 2.4 mA (previous 2.0 mA)
• Added a specification to cover the Normal mode switch detection threshold hysteresis.
• Updated minimum limit on Switch detection threshold in LPM to 80 mV
• Updated minimum ratio for switch threshold at low battery to 0.55x (previous 0.8x)
• Fixed typo on Input threshold specifications to VDD*0.25 and VDD*0.7
• Updated the INT_B VOL maximum level to 0.5 V (previous 0.4 V)
• Updated limits on the POR to Active time to 250 s (min) to 450 s (max) (previous min was 40 s)
• Clarified Operating voltage range (4.5 V to 28 V)
3.0
12/2014
• Corrected WAKE_B Max rating to 40 V.
• Added Figure 19, SPI Write Operation and Figure 20, SPI Read Operation
• Added Table 7.10.1, SPI Check
• Corrected Rb/W bits on Table 11 From 1/0 to 0/1
• Clarified SPI Read/write operation and SPI registers information.
• Updated VBATP(POR) maximum voltage to 3.8 V.
• Updated VBATP under voltage hysteresis minimum voltage to 250 mV
• Updated VBATP low power mode supply current to 40 uA
• Input logic voltage threshold WAKE_B typical value added at 1.25 V, max value updated to 1.7 V
• Added new Specification for WAKE_B input logic hysteresis.
• Clarified AMUX accuracy and Coefficient accuracy specifications, added Figure 4, Divide by 6 Coefficient Accuracy.
• Update internal pull-up resistance to 270 K (INT_B, WAKE_B, CS_B)
• Low Power Mode oscillator frequency centered at 192 KHz with +/- 15% tolerance.
• Updated all timing specs derived from the 192 kHz oscillator (Low-power mode)
• Added SBPOLLTIME (bit 13) selection functionality on 7.10.2, “Device Configuration Register"
• Added SB Tactive Polling time specification (58 s or 1.2 ms Typical)
• Table 6 Clarified wetting current specification for SB and SG channels.
• SB sustain Current and Low power mode polling current SB Typical value centered at 2.2mA, Min = 1.75 mA and
Max = 2.65 mA, (+/- 20% tolerance).
• Wetting current matching, Max value updated to 6%
• Updated Switch detection Threshold in Low Voltage maximum value to 4.3 V.
• Added Figure 22, Pulsed/Continuos Wetting Current Configuration
• Removed section (Electrical Test requirement, Stress testing, and EMC consideration)
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REVISION
DATE
DESCRIPTION OF CHANGES
• Changed VESD1-2 to ±2000
4.0
12/2014
• Changed ISUSSB max. value to 2.85 mA
• Changed IACTIVEPOLLSB max. value to 2.85 mA
• Changed PC33978EK and PC34978EK parts to MC in the Orderable Part Variations table
• Deleted PC33978ES and PC34978ES part numbers
• Updated case outline
8/2015
• Added new part numbers MC33978AEK, MC33978AES, MC34978AEK, and MC34978AES to the Orderable Part
Variations table
• Updated AMUX specification for QFN package
5.0
• Added thermal characteristics for QFN package
8/2015
• Updated VBATP HBM specification to 4.0 KV
• Added additional line to VESD1-2 spec in Table 3 to show the max. value for MC33978/MC34978 and MC33978A/
MC34978A
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© 2015 Freescale Semiconductor, Inc.
Document Number: MC33978
Rev. 5.0
8/2015
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