ESIEX(tsm)
ESISHTSM
1
1
1
0
ESICH0
ESICOM
Sample-and-Hold
ESILCEN(tsm)
ESITEN
1
0
Damping
Excitation
ESIDVSS
1
0
Excitation
=00
VMID Gen
ESIVMIDEN
1/2
AV
CC
1
0
00
01
10
11
00
01
10
11
to AFE1
Comparator
From
Channel
Select Logic
ESISH
2
ESIDVSS
AV
SS
ESI Operation
970
SLAU367P – October 2012 – Revised April 2020
Copyright © 2012–2020, Texas Instruments Incorporated
Extended Scan Interface (ESI)
Figure 37-4. Excitation and Sample-And-Hold Circuitry
37.2.1.2 Mid-Voltage Generator
The mid-voltage generator is on when ESIVMIDEN = 1 and allows the LC sensors to oscillate freely. The
mid-voltage generator requires a maximum of 6 ms to settle and requires ACLK to be active and operating
at 32768 Hz.
37.2.1.3 Sample-And-Hold
Note that the sample-and-hold circuit is only available in the analog front-end AFE1.
The sample-and-hold is used to sample the sensor voltage to be measured.
shows the
sample-and-hold circuitry. When ESISH = 1 and ESITEN = 0, the sample-and-hold circuitry is enabled and
the excitation circuitry and mid-voltage generator are disabled. The sample-and-hold is used for resistive
dividers or for other analog signals that should be sampled.