Programming HID Bootloader on PIC32

The bootloader is used to install programs on the PIC32 without using an external programmer like ICD2 and does not require any drivers on the computer. The PC software for the bootloader for the PC has already been installed with the Microchip Applications Library.

Software

PIC software

Download the PIC32 bootloader source files here. These files were tested with the Applications Library updated on November 17, 2009. If this library has been updated since then, these files may not work.

I recommend placing these files in a new folder. This will become your project folder.

PC software

If you downloaded the Microchip Applications Library, the PC HID Bootloader program is located under the start menu Programs -> Microchip -> MCHPFSUSB v2.6 -> Tools -> HIDBootLoader Running this requires a sufficiently recent version of the .NET Framework, which you may not have if you are running XP or earlier versions of Windows. You can download a sufficiently recent version here (the install takes a while): .NET Framework download.

Required circuitry

For the UBW32 and NU32 board, this circuitry is already on the board and this section can be ignored. This information is for people who are interested in making their own board.

A button must be wired to a pin that has been initialized as a digital input (similar to the RESET button). This PROGRAM button is used to put the PIC in Bootloading Mode. The UBW32 and NU32 board has the button wired to PIN E7 and PIN E5, respectively. The button can be put on any pin that supports digital input, but the bootloading program will have to be modified accordingly.

The PIC goes into Bootloading Mode when the PROGRAM button is held down when a RESET is called (ie hold down both PROGRAM and RESET and then release RESET). LEDS on the boards will flash to indicate that the PIC is in Bootloading Mode.

Installing a Bootloader on the PIC32 with ICD2

These directions detail how to start a new MPLAB project and program the HID Bootloader on the PIC32 with the Microchip MPLAB ICD 2 (In-Circuit Debugger). Before starting, Microchip MPLAB, Microchip C32 Compiler and the Microchip Applications Library must be installed.

Starting a New MPLAB Project

• Open MPLAB IDE.

• Choose Configure>Select Device to select the PIC you are working with. In the Device dialog, select the PIC you are using from the list if it’s not already selected. The lights show which software is supported for that PIC.

• Choose Project>Project Wizard to start a new project. Click Next

• Select the PIC from the drop down menu. Click Next

• Select the Microchip PIC32 C-Compiler Toolsuite from the drop down menu. Click Next

• Create a new project (I called it HIDBoot) in the folder where you want the project to be stored. I recommend creating a folder that contains the source code for each project. Click Next

• Add the following the c files to the project.
  • HardwareProfile.h (generic header file for many different boards)
  • HardwareProfile_NU32.h (hardware profile for the NU32, if you have your own hardware profile you will need to add it to the generic HardwareProfile.h)
  • main.c (the main source file)
  • main.h
  • procdefs.ld (a linker file read here for more discussion of why this linker file is important)
  • usb_config.h (header file to configure usb communication)
  • usb_descriptors.c (source file for usb communication)

Click Next

• Click Finish

Creating Bootloader Hex File

After clicking finish, MPLAB should appear as below. On the right is the project window which contains all of the files you have added to the project. The procdefs.ld file is located under the linker file folder. This file is not the only linker file, so it needs to be moved (dragged) to the 'Other Files' folder. The procdefs.ld file tells the programmer or bootloader where to put the files. The bootloader will have a different procdefs file than the files you will load with the bootloader because you want the new programs to be put in a different spot than the bootloader on the PIC. If you use the same procdefs file as the bootloader procdefs, the bootloader will try to put the new program where the bootloader code is stored, essentially erasing the bootloader and not installing the new program. If you accidently use the bootloader procdefs file, you will have to reinstall the bootloader on the PIC.

MPLAB needs to be pointed to the location of the header files of the Microchip Framework.

• Choose Project>Build Options>Project.
• In the directories tab, choose the Include Search Path from the drop down menu.
• Add a New path - Browse to find the include folder (<Installation Folder> \Microchip Solutions\Microchip\Include)
• Add a New path - Browse to find the folder where you have the project
• Click OK

Since the bootloader uses the USB source files of the Microchip Framework, we need to add the source files and some USB header files to the project. I put these files in sub-folders in the project window as noted below.

• In the project window, right click on 'Source Files' and click 'Create Subfolder'. I called the folder 'USB Framework'
• Right click on the new folder and select 'Add Files'
• Add the following files
  • usb_device.c from ... -> Microchip Solutions -> Microchip -> USB
  • usb_function_hid.c from ... -> Microchip Solutions -> Microchip -> USB -> HID Device Driver
• In the project window, right click on 'Header Files' and click 'Create Subfolder'. I called the folder 'USB Framework'
• Right click on the new folder and select 'Add Files'
• Add the following files from ... -> Microchip Solutions -> Microchip -> Include -> USB
  • usb.h
  • usb_ch9.h
  • usb_common.h
  • usb_device.h
  • usb_function_hid.h
  • usb_hal.h
  • usb_hal_pic32.h

Since we have a generic HardwareProfile we need to tell MPLAB which board we are using. We are essentially going to give MPLAB a constant that indicates which board to use.

• Choose Project -> Build Options and click on the MPLAB PIC32 C Compiler Tab
• The window for preprocessor macros is currently empty. We want to create a variable that is defined for our board. Click Add and type PIC32_NU32 if using the Northwestern PIC32 board.
• Click OK

We want the Bootloader Hex file to be as small as possible to occupy the least space on the PIC. Therefore, we want to optimize the compiler to have the smallest code size. If you do not minimize the code size, the bootloader will not work.

• Click Project -> Build Options and click on the MPLAB PIC32 C Compiler Tab as before
• Click on the Category "Optimization"
• Select the dot 's' for smallest size as shown below

If you are using the PIC32_NU32, you are ready to compile the project. If you are using a board other than the PIC32_NU32, make sure you follow all the directions in Notes for Loading Bootloader with Own Board.

• Choose Project -> Build All

This compiles and creates a Hex File in the project folder to be loaded on to the PIC.

Loading Bootloader on PIC with ICD2

These directions detail how to load a file (in this case a bootloader) on the PIC with ICD2 (In Circuit-Debugger)

These directions assume the following things:

• Circuit capable of programming the PIC already exists(discussed below)
• You have an ICD2
• You already have a hex file to load (the bootloader hex file was created with the above instructions)

Hardware Setup

The ICD2 comes with a 6 pin modular cable (we only need 5 of the pins). This is essentially a telephone wire with 2 extra wires. This tutorial assumes that your board only has 5 pins and not the jack for this cable. The pins on the cable are arranged as shown in the picture

Take note of the colors for each pin (i.e. pin 1 is blue, pin 2 is yellow, etc.). Cut one jack off, so that the wires are free. Solder these wires into a 5-pin header (do not solder the 6th pin) in the correct order. This will make it easier to connect the pins from the board to the cable.

The NU32 has the pins necessary for programming with ICD next to each other. Connect the pins to the correct pin of the header as detailed below

• MCLR - Pin 1
• 3.3V - Pin 2
• GND - Pin 3
• PGD - Pin 4
• PGC - Pin 5

PC Setting Up ICD2

This instructions assume you have already installed MPLAB, but have not installed the ICD2 on your computer yet.

• Connect the ICD2 to your PC with the USB cable.

• Do not allow Windows to pick a USB driver. When the found new hardware wizard pops up, select "Install from a List or Specific Location (Advanced)". Make sure the "Search for Best Driver" is Selected and unselect "Search Removable Media". Also select "Include this location in the search". Browse to the following directory "C:\Program Files\Microchip\MPLAB IDE\ICD2\Drivers" and click Next.

• Click finish on the "Completing the Found New Hardware Wizard"

• Another "Found New Hardware Wizard" screen will appear for the Firmware Client. Follow the same steps as above.

• Connect the ICD2 with the modified jack to your board. The pins are shown again below
  • MCLR - Pin 1
  • 3.3V - Pin 2
  • GND - Pin 3
  • PGD - Pin 4
  • PGC - Pin 5

If you have a program running on the PIC it will be interrupted when you connect the ICD2 to the board.

You program with the ICD2 in MPLAB. If MPLAB is not open, open MPLAB. You need to configure MPLAB to use the ICD2 programmer.

• Select Programmer -> Select Programmer -> MPLAB ICD 2.
• If a window doesn't appear, click Programmer -> MPLAB ICD2 Setup Wizard. I used the following set up features.
  • USB com port
  • ICD2 does NOT automatically connect
  • ICD2 automatically downloads OS

You are now ready to program.

Programming with ICD2

These instructions assume you already have installed and connected the ICD2 to the board and have a hex file created.

• With the board connected to the ICD2, click Programmer -> Connect.

The output window should say something similar to this:

  Connecting to MPLAB ICD 2
  ...Connected
  Setting Vdd source to target
  Target Device PIC32MX440F512H found, revision = Rev 0x50900053
  ...Reading ICD Product ID
  Running ICD Self Test
  ...Passed

If it says:

  Connecting to MPLAB ICD 2
  ...Connected
  Setting Vdd source to target
  ICD0042: API:  Error response (Device not ready (0x12))
  ICD0042: API:  Error response (Device not ready (0x12))
  MPLAB ICD 2 ready for next operation

I find that if you turn off the board and turn it back on, it works.

• Click File ->Import and find the hex file you created above.

This imports the hex file that you want to load on to the PIC.

• Click Programmer -> Program

The output window will say something similar to this:

  Programming Target...
  ...Validating configuration fields
  ...Erasing Part
  ...Loading Program Executive
  ...Programming Boot Config (0x1FC00000 - 0x1FC003FC)
  ...Verifying Boot Config memory (0x1FC00000 - 0x1FC003FC)
  ...Programming Program Memory (0x1D000000 - 0x1D0001FC)
  ...Verifying Program memory (0x1D000000 - 0x1D0001FC)
  ...Programming Program Memory (0x1D001400 - 0x1D0017FC)
  ...Verifying Program memory (0x1D001400 - 0x1D0017FC)
  ...Programming Program Memory (0x1D002000 - 0x1D005FFC)
  ...Verifying Program memory (0x1D002000 - 0x1D005FFC)
  ...Programming Configuration Bits
  ...Verifying Config memory
  ...Programming succeeded

The programmer is still attached to the PIC, so the PIC will not be running the program you just loaded.

• Click Programmer ->Release from Reset

Unfortunately, the ICD2 sometimes crashes MPLAB with PIC32. If we had ICD3 in the lab, I would use that one instead.

The bootloader is now installed on the PIC.

If getting started click here to return to the instructions.

See Directions to Load Files to PIC32 with HID Bootloader

Notes for Loading Bootloader with Own Board

If you are loading a bootloader with a board that is not included in the HardwareProfile header file. You will need to do the following tasks.

• Define a board constant in MPLAB PIC32 C Compiler Tab in Project -> Build options (ex. PIC32_NU32)
• Put the following line in the HardwareProfile under the correct compiler (ex __C32__) and PIC (ex __32MX460F512L__)

  #elif defined(YOUR_BOARD_CONSTANT)
     #include "YOUR_HARDWAREPROFILE.h"

where YOUR_BOARD_CONSTANT is the constant you put in the compiler tab and YOUR_HARDWAREPROFILE.h is the profile header file for your board.

• In main.c, you will need to add a section for the configuration bits for your board as shown below:

  #elif defined(YOUR_BOARD_CONSTANT)
     the configuration...