8.1 Introduction
The ADC module described in this chapter is a 12-bit recyclic ADC; part SAR, part pipelined. The analog
circuits of this converter, referred to as the "core" in this document, include the front-end analog multiplexers
(MUXs), sample-and-hold (S+H) circuits, the conversion core, voltage regulators, and other analog supporting
circuits. Digital circuits, referred to as the "wrapper" in this document, include programmable conversions, result
registers, interface to analog circuits, interface to device peripheral bus, and interface to other on-chip modules.
8.1.1 Features
The core of the ADC contains a single 12-bit converter fed by two sample and hold circuits. The sample and hold
circuits can be sampled simultaneously or sequentially. These, in turn, are fed by a total of up to 16 analog input
channels. See your device-specific data sheet for the specific number of channels available. The converter can
be configured to run with an internal bandgap reference to create true-voltage based conversions or with a pair
of external voltage references (VREFHI/LO) to create ratiometric based conversions.
Contrary to previous ADC types, this ADC is not sequencer based. It is easy for the user to create a series of
conversions from a single trigger. However, the basic principle of operation is centered around the configurations
of individual conversions, called SOCs, or Start-Of-Conversions.
Functions of the ADC module include:
• 12-bit ADC core with built-in dual sample-and-hold (S+H)
• Simultaneous sampling or sequential sampling modes
• Full range analog input: 0 V to 3.3 V fixed, or VREFHI/VREFLO ratiometric
• Up to 16-channel, multiplexed inputs
• 16 SOCs, configurable for trigger, sample window, and channel
• 16 result registers (individually addressable) to store conversion values
• Multiple trigger sources
– S/W - software immediate start
– ePWM 1-8
– GPIO XINT2
– CPU Timers 0/1/2
– ADCINT1/2
• 9 flexible PIE interrupts, can configure interrupt request after any conversion
8.1.2 ADC Related Collateral
Foundational Materials
•
ADC Input Circuit Evaluation for C2000 MCUs (TINA-TI) Application Report
•
PSpice for TI design and simulation tool
•
Real-Time Control Reference Guide
– Refer to the ADC section
•
(Video)
– Start with the "Introduction to analog-to-digital converters (ADCs)" section.
•
•
TI Precision Labs: Driving the reference input on a SAR ADC
(Video)
•
TI Precision Labs: Introduction to analog-to-digital converters (ADCs)
(Video)
•
TI Precision Labs: SAR ADC input driver design
(Video)
•
TI e2e: Connecting VDDA to VREFHI
•
TI e2e: Topologies for ADC Input Protection
•
TI e2e: Why does the ADC Input Voltage drop with sampling?
– Sampling a high impedance voltage divider with ADC
•
Understanding Data Converters Application Report
Analog-to-Digital Converter (ADC)
510
TMS320x2806x Microcontrollers
SPRUH18I – JANUARY 2011 – REVISED JUNE 2022
Copyright © 2022 Texas Instruments Incorporated
Содержание TMS320 2806 Series
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