Texas Instruments TMS320x281 series User manual

TMS320x281x
Enhanced Controller Area Network (eCAN)
Reference Guide
Literature Number: SPRU074FMay 2002 – Revised January 2009

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Contents
Preface ............................................................................................................................... 7
1 Architecture ............................................................................................................... 91.1 CAN Overview .............................................................................................................. 101.1.1 Features ............................................................................................................ 101.1.2 Block Diagram ..................................................................................................... 111.1.3 eCAN Compatibility With Other TI CAN Modules ............................................................. 111.2 The CAN Network and Module ........................................................................................... 121.2.1 CAN Protocol Overview .......................................................................................... 121.3 eCAN Controller Overview ................................................................................................ 131.3.1 Standard CAN Controller (SCC) Mode ......................................................................... 141.3.2 Memory Map ....................................................................................................... 151.3.3 eCAN Control and Status Registers ............................................................................ 181.4 Message Objects ........................................................................................................... 191.5 Message Mailbox ........................................................................................................... 191.5.1 Transmit Mailbox .................................................................................................. 231.5.2 Receive Mailbox ................................................................................................... 241.5.3 CAN Module Operation in Normal Configuration.............................................................. 24
2 eCAN Registers ........................................................................................................ 252.1 Mailbox Enable Register (CANME) ...................................................................................... 262.2 Mailbox-Direction Register (CANMD) .................................................................................... 272.3 Transmission-Request Set Register (CANTRS) ....................................................................... 282.4 Transmission-Request-Reset Register (CANTRR) .................................................................... 292.5 Transmission-Acknowledge Register (CANTA) ........................................................................ 302.6 Abort-Acknowledge Register (CANAA) .................................................................................. 312.7 Received-Message-Pending Register (CANRMP) ..................................................................... 322.8 Received-Message-Lost Register (CANRML) .......................................................................... 332.9 Remote-Frame-Pending Register (CANRFP) .......................................................................... 342.9.1 Handling of Remote Frames ..................................................................................... 342.10 Global Acceptance Mask Register (CANGAM)......................................................................... 362.11 Master Control Register (CANMC) ....................................................................................... 372.11.1 CAN Module Action in SUSPEND ............................................................................. 392.12 Bit-Timing Configuration Register (CANBTC) .......................................................................... 402.13 Error and Status Register (CANES) ..................................................................................... 422.14 CAN Error Counter Registers (CANTEC/CANREC) ................................................................... 442.15 Interrupt Registers.......................................................................................................... 452.15.1 Global Interrupt Flag Registers (CANGIF0/CANGIF1) ...................................................... 452.15.2 Global Interrupt Mask Register (CANGIM) .................................................................... 482.15.3 Mailbox Interrupt Mask Register (CANMIM) .................................................................. 502.15.4 Mailbox Interrupt Level Register (CANMIL) ................................................................... 512.16 Overwrite Protection Control Register (CANOPC) ..................................................................... 522.17 eCAN I/O Control Registers (CANTIOC, CANRIOC) .................................................................. 53
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2.18 Timer Management Unit ................................................................................................... 552.18.1 Time Stamp Functions ........................................................................................... 552.18.2 Time-Out Functions .............................................................................................. 582.18.3 Behavior/Usage of MTOF0/1 Bit in User Applications....................................................... 602.19 Mailbox Layout .............................................................................................................. 612.19.1 Message Identifier Register (MSGID) ......................................................................... 612.19.2 CPU Mailbox Access ............................................................................................ 622.19.3 Message-Control Register (MSGCTRL)....................................................................... 632.19.4 Message Data Registers (CANMDL, CANMDH) ............................................................. 642.20 Acceptance Filter ........................................................................................................... 652.20.1 Local-Acceptance Masks (CANLAM) .......................................................................... 65
3 eCAN Configuration .................................................................................................. 673.1 CAN Module Initialization.................................................................................................. 683.1.1 CAN Bit-Timing Configuration ................................................................................... 693.1.2 CAN Bit Rate Calculation ........................................................................................ 693.1.3 Bit Configuration Parameters for 150-MHz CAN Clock ...................................................... 703.1.4 Bit Configuration Parameters for 100-MHz CAN Clock ...................................................... 713.1.5 EALLOW Protection ............................................................................................... 723.2 Steps to Configure eCAN ................................................................................................. 723.2.1 Configuring a Mailbox for Transmit ............................................................................. 733.2.2 Transmitting a Message .......................................................................................... 733.2.3 Configuring Mailboxes for Receive.............................................................................. 733.2.4 Receiving a Message ............................................................................................. 743.2.5 Handling of Overload Situations ................................................................................. 743.3 Handling of Remote Frame Mailboxes .................................................................................. 743.3.1 Requesting Data From Another Node .......................................................................... 743.3.2 Answering a Remote Request ................................................................................... 753.3.3 Updating the Data Field .......................................................................................... 753.4 Interrupts .................................................................................................................... 753.4.1 Interrupts Scheme ................................................................................................. 773.4.2 Mailbox Interrupt ................................................................................................... 773.4.3 Interrupt Handling ................................................................................................. 783.5 CAN Power-Down Mode .................................................................................................. 803.5.1 Entering and Exiting Local Power-Down Mode ............................................................... 803.5.2 Precautions for Entering and Exiting Device Low-Power Modes (LPM) ................................... 803.5.3 Enabling/Disabling Clock to the CAN Module ................................................................. 813.5.4 Possible Failure Modes External to the CAN Controller Module ............................................ 81
A Revision History ....................................................................................................... 83
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List of Figures
1-1 eCAN Block Diagram and Interface Circuit ............................................................................. 111-2 CAN Data Frame ........................................................................................................... 121-3 Architecture of the eCAN Module ........................................................................................ 131-4 eCAN-A Memory Map ..................................................................................................... 161-5 eCAN-B Memory Map ..................................................................................................... 172-1 Mailbox-Enable Register (CANME) ...................................................................................... 262-2 Mailbox-Direction Register (CANMD) .................................................................................... 272-3 Transmission-Request Set Register (CANTRS) ....................................................................... 282-4 Transmission-Request-Reset Register (CANTRR) .................................................................... 292-5 Transmission-Acknowledge Register (CANTA) ........................................................................ 302-6 Abort-Acknowledge Register (CANAA) .................................................................................. 312-7 Received-Message-Pending Register (CANRMP) ..................................................................... 322-8 Received-Message-Lost Register (CANRML) .......................................................................... 332-9 Remote-Frame-Pending Register (CANRFP) .......................................................................... 342-10 Global Acceptance Mask Register (CANGAM)......................................................................... 362-11 Master Control Register (CANMC) ....................................................................................... 372-12 Bit-Timing Configuration Register (CANBTC) .......................................................................... 402-13 Error and Status Register (CANES) ..................................................................................... 422-14 Transmit-Error-Counter Register (CANTEC) ........................................................................... 442-15 Receive-Error-Counter Register (CANREC) ............................................................................ 442-16 Global Interrupt Flag 0 Register (CANGIF0) ............................................................................ 462-17 Global Interrupt Flag 1 Register (CANGIF1) ............................................................................ 462-18 Global Interrupt Mask Register (CANGIM) .............................................................................. 482-19 Mailbox Interrupt Mask Register (CANMIM) ............................................................................ 502-20 Mailbox Interrupt Level Register (CANMIL) ............................................................................. 512-21 Overwrite Protection Control Register (CANOPC) ..................................................................... 522-22 TX I/O Control Register (CANTIOC) ..................................................................................... 532-23 RX I/O Control Register (CANRIOC) .................................................................................... 542-24 Time-Stamp Counter Register (CANTSC) .............................................................................. 562-25 Message Object Time Stamp Registers (MOTS) ...................................................................... 572-26 Message-Object Time-Out Registers (MOTO) ......................................................................... 582-27 Time-Out Control Register (CANTOC) .................................................................................. 592-28 Time-Out Status Register (CANTOS) ................................................................................... 602-29 Message Identifier Register (MSGID) Register......................................................................... 612-30 Message-Control Register (MSGCTRL) ................................................................................. 632-31 Message-Data-Low Register With DBO = 0 (CANMDL) .............................................................. 642-32 Message-Data-High Register With DBO = 0 (CANMDH) ............................................................. 642-33 Message-Data-Low Register With DBO = 1 (CANMDL) .............................................................. 642-34 Message-Data-High Register With DBO = 1 (CANMDH) ............................................................. 642-35 Local-Acceptance-Mask Register (LAM n).............................................................................. 663-1 Initialization Sequence ..................................................................................................... 683-2 CAN Bit Timing ............................................................................................................. 693-3 Interrupts Scheme .......................................................................................................... 76
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List of Tables
1-1 Register Map ................................................................................................................ 181-2 eCAN-A Mailbox RAM Layout ............................................................................................ 201-3 Addresses of LAM, MOTS and MOTO registers for mailboxes (eCAN-A) ......................................... 211-4 eCAN-B Mailbox Ram Layout ............................................................................................ 221-5 Addresses of LAM, MOTS, and MOTO Registers for Mailboxes (eCAN-B) ........................................ 231-6 Message Object Behavior Configuration ................................................................................ 232-1 Mailbox-Enable Register (CANME) Field Descriptions ................................................................ 262-2 Mailbox-Direction Register (CANMD) Field Descriptions ............................................................. 272-3 Transmission-Request Set Register (CANTRS) Field Descriptions ................................................. 282-4 Transmission-Request-Reset Register (CANTRR) Field Descriptions .............................................. 292-5 Transmission-Acknowledge Register (CANTA) Field Descriptions .................................................. 302-6 Abort-Acknowledge Register (CANAA) Field Descriptions ........................................................... 312-7 Received-Message-Pending Register (CANRMP) Field Descriptions .............................................. 322-8 Received-Message-Lost Register (CANRML) Field Descriptions.................................................... 332-9 Remote-Frame-Pending Register (CANRFP) Field Descriptions .................................................... 342-10 Global Acceptance Mask Register (CANGAM) Field Descriptions .................................................. 362-11 Master Control Register (CANMC) Field Descriptions ................................................................ 372-12 Bit-Timing Configuration Register (CANBTC) Field Descriptions .................................................... 402-13 Error and Status Register (CANES) Field Descriptions ............................................................... 422-14 Global Interrupt Flag Registers (CANGIF0/CANGIF1) Field Descriptions .......................................... 472-15 Global Interrupt Mask Register (CANGIM) Field Descriptions ....................................................... 482-16 Mailbox Interrupt Mask Register (CANMIM) Field Descriptions ...................................................... 502-17 Mailbox Interrupt Level Register (CANMIL) Field Descriptions ...................................................... 512-18 Overwrite Protection Control Register (CANOPC) Field Descriptions .............................................. 522-19 TX I/O Control Register (CANTIOC) Field Descriptions .............................................................. 532-20 RX I/O Control Register (CANRIOC) Field Descriptions .............................................................. 542-21 Time-Stamp Counter Register (CANTSC) Field Descriptions ........................................................ 562-22 Message Object Time Stamp Registers (MOTS) Field Descriptions ................................................ 572-23 Message-Object Time-Out Registers (MOTO) Field Descriptions ................................................... 582-24 Time-Out Control Register (CANTOC) Field Descriptions ............................................................ 592-25 Time-Out Status Register (CANTOS) Field Descriptions ............................................................. 602-26 Message Identifier Register (MSGID) Field Descriptions ............................................................. 612-27 Message-Control Register (MSGCTRL) Field Descriptions .......................................................... 632-28 Local-Acceptance-Mask Register (LAM n) Field Descriptions ........................................................ 663-1 BRP Field for Bit Rates (BT = 15, TSEG1
reg
= 10, TSEG2
reg
= 2, Sampling Point = 80%) ...................... 703-2 Achieving Different Sampling Points With a BT of 15 ................................................................. 703-3 BRP Field for Bit Rates (BT = 10, TSEG1
reg
= 6, TSEG2
reg
= 1, Sampling Point = 80%) ........................ 703-4 BRP Field for Bit Rates (BT = 10, TSEG1
reg
= 6, TSEG2
reg
= 1, Sampling Point = 80%) ........................ 713-5 Achieving Different Sampling Points With a BT of 20 ................................................................. 713-6 BRP Field for Bit Rates .................................................................................................... 713-7 eCAN Interrupt Assertion/Clearing ....................................................................................... 78A-1 Changes Made in This Revision ......................................................................................... 83
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PrefaceSPRU074F – May 2002 – Revised January 2009
Read This First
About This Manual
This document describes the enhanced controller area network (eCAN) on the x281x device.
Notational Conventions
This document uses the following conventions.•Hexadecimal numbers are shown with the suffix h. For example, the following number is 40hexadecimal (decimal 64): 40h.
Related Documentation From Texas Instruments
The following documents describe the x281x device and related peripherals. Copies of these documentsare available for downloading at www.ti.com .
CPU User's Guides—SPRU430— TMS320C28x DSP CPU and Instruction Set Reference Guide describes the centralprocessing unit (CPU) and the assembly language instructions of the TMS320C28x fixed-pointdigital signal processors (DSPs). It also describes emulation features available on these DSPs.
SPRU078— TMS320x281x System Control and Interrupts Reference Guide describes the variousinterrupts and system control features of the 281x digital signal processors (DSPs).
Peripheral Guides—SPRU566— TMS320x28xx, 28xxx DSP Peripheral Reference Guide describes the peripheral referenceguides of the 28x digital signal processors (DSPs).
SPRU060— TMS320x281x Analog-to-Digital Converter (ADC) Reference Guide describes the ADCmodule, which is a 12-bit pipelined ADC. The analog circuits of this converter, referred to as thecore 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. Digitalcircuits, referred to as the wrapper in this document, include programmable conversion sequencer,result registers, interface to analog circuits, interface to device peripheral bus, and interface to otheron-chip modules.
SPRU065— TMS320x281x Event Manager (EV) Reference Guide describes the EV modules that providea broad range of functions and features that are particularly useful in motion control and motorcontrol applications. The EV modules include general-purpose (GP) timers, full-compare/pulsewidth modulator (PWM) units, capture units, and quadrature-encoder pulse (QEP) circuits.
SPRU074— TMS320x28xx, 28xxx Enhanced Controller Area Network (eCAN) Reference Guide describesthe eCAN that uses established protocol to communicate serially with other controllers in electricallynoisy environments.
SPRU051— TMS320x28xx, 28xxx Serial Communication Interface (SCI) Reference Guide describes theSCI, which is a two-wire asynchronous serial port, commonly known as a UART. The SCI modulessupport digital communications between the CPU and other asynchronous peripherals that use thestandard non-return-to-zero (NRZ) format.
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Related Documentation From Texas Instruments www.ti.com
SPRU059— TMS320x28xx, 28xxx Serial Peripheral Interface (SPI) Reference Guide describes the SPI -a high-speed synchronous serial input/output (I/O) port - that allows a serial bit stream ofprogrammed length (one to sixteen bits) to be shifted into and out of the device at a programmedbit-transfer rate.
SPRU061— TMS320x281x Multi-channel Buffered Serial Ports (McBSPs) Reference Guide describes theMcBSP available on the C28x devices. The McBSPs allow direct interface between a DSP andother devices in a system.
SPRU067— TMS320x281x External Interface (XINTF) Reference Guide describes the external interface(XINTF) of the 281x digital signal processors (DSPs).
SPRU095— TMS320x281x Boot ROM Reference Guide describes the purpose and features of thebootloader (factory-programmed boot-loading software). It also describes other contents of thedevice on-chip boot ROM and identifies where all of the information is located within that memory.
Tools Guides—
SPRU513— TMS320C28x Assembly Language Tools User's Guide describes the assembly languagetools (assembler and other tools used to develop assembly language code), assembler directives,macros, common object file format, and symbolic debugging directives for the TMS320C28x device.
SPRU514— TMS320C28x Optimizing C Compiler User's Guide describes the TMS320C28x™ C/C++compiler. This compiler accepts ANSI standard C/C++ source code and produces TMS320 DSPassembly language source code for the TMS320C28x device.
SPRU608— The TMS320C28x Instruction Set Simulator Technical Overview describes the simulator,available within the Code Composer Studio for TMS320C2000 IDE, that simulates the instructionset of the C28x™ core.
SPRU625— TMS320C28x DSP/BIOS Application Programming Interface (API) Reference Guidedescribes development using DSP/BIOS.
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Chapter 1SPRU074F – May 2002 – Revised January 2009
Architecture
The enhanced Controller Area Network (eCAN) module implemented in the C28x™ DSP is a full-CANcontroller and is compatible with the CAN 2.0B standard (active). It uses established protocol tocommunicate serially with other controllers in electrically noisy environments. With 32 fully configurablemailboxes and time–stamping feature, the eCAN module provides a versatile and robust serialcommunication interface.
The eCAN module described in this reference guide is a Type 0 eCAN. Refer to theTMS320x28xx, 28xxxDSP Peripheral Reference Guide (SPRU566 ) for a list of other devices with a eCAN module of the sametype, to determine the differences between types, and for a list of device-specific differences within a type.Some devices have a second CAN module, eCAN-B. The word eCAN is generically used to refer to theCAN modules. The specific module reference (A or B) is used where appropriate. For a given CANmodule, the same address space is used for the module registers in all 28xx /28xxx devices.
Topic .................................................................................................. Page
1.1 CAN Overview .......................................................................... 101.2 The CAN Network and Module .................................................... 121.3 eCAN Controller Overview ......................................................... 131.4 Message Objects....................................................................... 191.5 Message Mailbox ...................................................................... 19
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1.1 CAN Overview
1.1.1 Features
CAN Overview www.ti.com
Figure 1–1 shows the major blocks of the eCAN and the interface circuits.
The eCAN module has the following features:•Fully compliant with CAN protocol, version 2.0B•Supports data rates up to 1 Mbps•Thirty-two mailboxes, each with the following properties:– Configurable as receive or transmit– Configurable with standard or extended identifier– Has a programmable acceptance filter mask– Supports data and remote frame– Supports 0 to 8 bytes of data– Uses a 32-bit time stamp on received and transmitted message– Protects against reception of new message– Allows dynamically programmable priority of transmit message– Employs a programmable interrupt scheme with two interrupt levels– Employs a programmable interrupt on transmission or reception time-out•Low–power mode•Programmable wake–up on bus activity•Automatic reply to a remote request message•Automatic retransmission of a frame in case of loss of arbitration or error•32-bit time-stamp counter synchronized by a specific message (communication in conjunction withmailbox 16)•Self–test mode– Operates in a loopback mode receiving its own message. A “dummy” acknowledge is provided,thereby eliminating the need for another node to provide the acknowledge bit.
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