AN1388 â PIC32 Bootloader - Microchip

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AN1388APPENDIX A:SOURCE CODESoftware License AgreementThe software supplied herewith by Microchip Technology Incorporated (the “Company”) is intended and supplied to you, theCompany’s customer, for use solely and exclusively with products manufactured by the Company.The software is owned by the Company and/or its supplier, and is protected under applicable copyright laws. All rights are reserved.Any use in violation of the foregoing restrictions may subject the user to criminal sanctions under applicable laws, as well as to civilliability for the breach of the terms and conditions of this license.THIS SOFTWARE IS PROVIDED IN AN “AS IS” CONDITION. NO WARRANTIES, WHETHER EXPRESS, IMPLIED ORSTATUTORY, INCLUDING, BUT NOT LIMITED TO, IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR APARTICULAR PURPOSE APPLY TO THIS SOFTWARE. THE COMPANY SHALL NOT, IN ANY CIRCUMSTANCES, BE LIABLEFOR SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES, FOR ANY REASON WHATSOEVER.All of the software covered in this application note isavailable as a single WinZip archive file. This archivecan be downloaded from the Microchip corporate Website at:www.microchip.comDS01388B-page 8© 2011-2012 Microchip Technology Inc.
AN1388APPENDIX B:BOOTLOADERCOMMUNICATIONPROTOCOL (UART,USB HID, ANDETHERNET)The PC host application uses a communicationprotocol to interact with the bootloader firmware. ThePC host application acts as a master and issuescommands to the bootloader firmware to performspecific operations.Frame FormatThe communication protocol follows the frame format,as shown in Example 1. The frame format remains thesame in both directions, that is, from the hostapplication to the bootloader, and from the bootloaderto the host application.EXAMPLE 1: FRAME FORMAT[…][…]Where: Represents a byte[...] Represents an optional or variable number of bytesThe frame starts with a control character, Start ofHeader (SOH), and ends with another control character,End of Transmission (EOT). The integrity of the frame isprotected by two bytes of Cyclic Redundancy Check(CRC)-16, represented by CRCL (low-byte) and CRCH(high-byte).Control CharactersSome bytes in the Data field may imitate the controlcharacters, SOH and EOT. The Data LinkEscape (DLE) character is used to escape such bytesthat could be interpreted as control characters. Thebootloader always accepts the byte following a as data, and always sends a before any of thecontrol characters.TABLE 3:CONTROL CHARACTERDESCRIPTIONSControl Hex Value Description 0x01 Marks the beginning of aframe 0x04 Marks the end of a frame 0x10 Data link escapeCommandsThe PC host application can issue the commands listedin Table 4 to the bootloader. The first byte in the datafield carries the command.TABLE 4:Command Valuein Hexadecimal0x010x020x030x040x05COMMAND DESCRIPTIONREAD BOOTLOADER VERSIONINFORMATIONThe PC host application request for version informationto the bootloader is shown in Example 2.EXAMPLE 2: REQUEST[…][]The bootloader responds to the PC request for versioninformation in two bytes, as shown in Example 3.EXAMPLE 3: RESPONSE[…]Where:MAJOR_VER – Major version of the bootloaderMINOR_VER – Minor version of the bootloaderERASE FLASHOn receiving the erase Flash command from the PChost application, the bootloader erases that part of theprogram Flash, which is allocated for the userapplication. The request frame from the PC hostapplication to the bootloader is shown in Example 4.EXAMPLE 4:REQUESTThe response frame from the bootloader to the PC hostapplication is shown in Example 5.EXAMPLE 5:RESPONSEDescriptionRead the bootloader versioninformationErase FlashProgram FlashRead CRCJump to application[…][…]© 2011-2012 Microchip Technology Inc. DS01388B-page 9
Page 1 and 2: AN1388PIC32 BootloaderAuthor:INTROD
Page 3 and 4: AN1388IMPLEMENTATION OVERVIEW(UART,
Page 5 and 6: AN1388HANDLING DEVICE CONFIGURATION
Page 7: AN1388RUNNING THE SD CARDBOOTLOADER
Page 11 and 12: AN1388APPENDIX C:CONSIDERATIONSWHIL
Page 13 and 14: AN1388EXAMPLE 12:LINES TO MODIFY IN
Page 15 and 16: AN1388APPENDIX E:BOOTLOADERWORKSPAC
Page 17 and 18: AN1388APPENDIX F:REVISION HISTORYRe
Page 19 and 20: Note the following details of the c

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AN1388 â PIC32 Bootloader - Microchip