Analog Front-End 2 (AFE2)
ESICI
ESICI3
ESICI2
ESICI1
ESICI0
ESICH2
ESICH3
ESICH1
ESICH0
ESICOM
ESIDVSS
Timing State Machine (TSM)
with oscillator
AVcc
DAC 12-Bit
with RAM
Se
n
so
r S
u
p
p
o
rt
½
+
-
Analog Input Multiplexer
To Timer_A
Interrupt
Request
Rotation
Data
ACLK
SMCLK
Pre-
Process-
ing Unit
Analog Front-End 1 (AFE1)
ESIDVCC
ESI RAM
MAB/
MDB/
MCB
from 32kHz
crystal osc.
Processing
State
Machine
(PSM)
PPUS1
PPUS2
PPUS3
ESIC2
OUT
ESIC1
OUT
PPUS1
PPUS2
TimerA
Output
Stage
Comp1
Out
ESI Introduction
966
SLAU367P – October 2012 – Revised April 2020
Copyright © 2012–2020, Texas Instruments Incorporated
Extended Scan Interface (ESI)
37.1 ESI Introduction
The ESI module is used to automatically measure linear or rotational motion with the lowest possible
power consumption. The ESI consists of following blocks: the analog front end (AFE1 and AFE2), the
preprocessing unit (PPU), the processing state machine (PSM) with its associated RAM, the timing state
machine (TSM), and the Timer_A Output Stage. The analog front end stimulates the sensors, senses the
signal levels, and converts them into their digital representation. The digital representations of a
measurement sequence are stored in the preprocessing unit. The stored digital signals are passed into
the processing state machine. The processing state machine is used to analyze and count rotation or
motion. The timing state machine controls the analog front end, the preprocessing unit, and the
processing state machine. The Timer_A Output Stage generates signals that are fed into Timer_A capture
inputs; this allows for time measurements (for example, LC-sensor envelope test).
The ESI features include:
•
Support for different types of sensors
–
LC sensors
–
Resistive sensors such as Hall-effect or giant magnetoresistive (GMR) sensors
–
Optical sensors
–
And more
•
Measurement of sensor signal envelope
•
Measurement of sensor signal oscillation amplitude
•
Direct analog input for analog-to-digital conversion
•
Direct digital input for digital sensors such as optical decoders
•
Support for quadrature decoding
shows the ESI module block diagram.
Figure 37-1. ESI Block Diagram