Data Sheet
AD5940
Using the Waveform Generator with the Low Power DAC ..92
Waveform Generator Registers .................................................93
SPI Interface.....................................................................................96
Overview ......................................................................................96
SPI Pins.........................................................................................96
SPI Operation ..............................................................................96
Command Byte............................................................................96
Writing to and Reading from Registers ...................................96
Reading Data from the Data FIFO ...........................................97
Sleep and Wake-Up Timer .............................................................98
Sleep and Wake-Up Timer Features .........................................98
Sleep and Wake-Up Timer Overview.......................................98
Configuring a Defined Sequence Order ..................................98
Recommended Sleep and Wake-Up Timer Operation..........98
Sleep and Wake-Up Timer Registers........................................99
Interrupts....................................................................................... 103
Interrupt Controller Interupts................................................ 103
Configuring the Interrupts ..................................................... 103
Custom Interrupts.................................................................... 103
External Interrupt Configuration .......................................... 103
Interrupt Registers ................................................................... 104
External Interrupt Configuration Registers ......................... 109
Digital Inputs/Outputs ................................................................ 113
Digital Inputs/Outputs Features............................................. 113
Digital Inputs/Outputs Operation..........................................113
GPIO Registers..........................................................................114
System Resets.................................................................................117
Analog Die Reset Registers......................................................117
Power Modes .................................................................................118
Active High Power Mode (>80 kHz)......................................118
Active Low Power Mode (<80 kHz) .......................................118
Hibernate Mode ........................................................................118
Shutdown Mode........................................................................118
Low Power Mode ......................................................................118
Power Modes Registers ............................................................118
Clocking Architecture ..................................................................121
Clock Features ...........................................................................121
Clock Architecture Registers...................................................121
Applications Information.............................................................125
EDA Bioimpedance Measurement Using a Low Bandwidth
Loop............................................................................................125
Body Impedance Analysis (BIA) Measurement Using a High
Bandwidth Loop........................................................................126
High Precision Potentiosat Configuration ............................127
Using the AD5940, AD8232, and AD8233 for Bioimpedance
and Electrocardiogram (ECG) Measurements .....................128
Smart Water/Liquid Quality AFE...........................................129
Outline Dimensions......................................................................130
Ordering Guide .........................................................................130
REVISION HISTORY
3/2019—Revision 0: Initial Version
Rev. 0 | Page 3 of 130