Power
Supply
Terminals
ESICI0
ESICI
ESICI1
ESICI2
ESICI3
AV
CC
DV
CC
DV
SS
AV
SS
ESIDVSS
470 nF
ESICOM
ESICH1
ESICH0
ESICH2
ESICH3
/ESIDVCC
0..1k
ESI Operation
988
SLAU367P – October 2012 – Revised April 2020
Copyright © 2012–2020, Texas Instruments Incorporated
Extended Scan Interface (ESI)
37.2.8.1.2 LC-Sensor Envelope Test
The envelop test measures the decay time of the oscillations after sensor excitation. The oscillation
envelope is created by the diodes and RC filters. The DAC is used to set the reference level for the
comparator, and the comparator detects if the oscillation envelop is above or below the reference level.
The comparator and AFE outputs are connected to Timer_A and the capture/compare registers for
Timer_A are used to time the decay of the oscillation envelope. The PSM is not used for the envelope
test.
When the sensors are connected to the individual ESICIx inputs as shown in
, the comparator
reference level can be adjusted for each sensor individually. When all sensors are connected to the ESICI
input as shown in
, only one comparator reference level is set for all sensors.
Figure 37-17. LC Sensor Connections For The Envelope Test