AN-1267
APPLICATION NOTE
One Technology Way • P. O. Box 9106 • Norwood, MA 02062-9106, U.S.A. • Te l: 781.329.4700 • Fax: 781.461.3113 • www.analog.com
Motor Control Feedback Sample Timing Using the
ADSP-CM408F ADC Controller
By Dara O’Sullivan, Jens Sorensen, and Aengus Murray
Rev. A | Page 1 of 18
INTRODUCTION
This application note introduces the main features of the
ADSP-CM408F analog-to-digital converter controller (ADCC)
blocks with a focus on relevance and usefulness in current
feedback systems of high performance motor control
applications.
The purpose of this application note is to highlight the key
capabilities of the analog-to-digital converter (ADC) module
and to provide guidance on its configuration for motor control
applications. Code samples illustrating the use of the ADCC
drivers from Analog Devices, Inc., are provided.
Further details on the full range of features, configuration registers,
and application program interfaces (APIs) for this ADCC can be
found in the ADSP-CM40x Mixed-Signal Control Processor with
ARM Cortex-M4 Hardware Reference Manual available on the
ADSP-CM402F/ADSP-CM403F/ADSP-CM407F/ADSP-CM408F
product pages, and on the ADSP-CM40x Mixed-Signal Control
Processor with ARM Cortex-M4 and 16-bit ADCs Development
Products product page.
While this application note is focused on current feedback, similar
principles of configuration and application are applicable to the
feedback and measurement of other signals.
Likewise, the focus of the application note is specifically on the
ADSP-CM408F; however, the principles are generally applicable
to the other parts within the ADSP-CM402F/ADSP-CM403F/
ADSP-CM407F/ADSP-CM408F family.
AN-1267 Application Note
TABLE OF CONTENTS
Introduction ...................................................................................... 1
Revision History ............................................................................... 2
Current Feedback System Overview .............................................. 3
ADC Module Overview ................................................................... 4
Current Feedback Scaling ................................................................ 5
ADC Timing Considerations .......................................................... 6
ADCC Event Timing.................................................................... 6
ADC Operational Timing ........................................................... 7
ADC Pipelining ............................................................................ 9
ADC Data Access ........................................................................... 10
ADCC Data Fault Detection ..................................................... 10
ADCC Module, Trigger Routing, and Memory Setup .............. 11
Configuration of ADCC Events ............................................... 11
Interrupts and Trigger Routing ................................................ 12
Data Access and Memory Allocation ...................................... 12
ADCC Software Support ............................................................... 13
Example Code ............................................................................. 13
Example Experimental Results ................................................. 18
REVISION HISTORY
9/14—Rev. 0 to Rev. A
Changes to Introduction Section .................................................... 1
Changes to Figure 2 .......................................................................... 3
Changes to Figure 3 .......................................................................... 4
Changes to Current Feedback Scaling Section ............................. 5
Changes to ADC Operational Timing Section ............................. 7
Added Adjustment of Sampling Instant Section and Figure 11;
Renumbered Sequentially ................................................................ 8
Added Trigger Routing for Enhanced Precision Sample
Timing Section ................................................................................ 12
Changes to Example Code Section .............................................. 13
9/13—Revision 0: Initial Version
Rev. A | Page 2 of 18