How to use Max32 with bootloader

[32bits]

I am using Max32 with an external programmer connected to the porgramming port J11 and this all works correctly. Now I want to program the Max32 and use the bootloader, the bootloader file to program the Max32 with I find on the Max32 webpage as chipkit-max32-v01000303.zip. My question is where to find the PC application which then talks with the Max32 which is running the bootloader via the USB port?   I don't want to run an Microchip software and hope you have a simple PC application to transfer a hex file to the Max32 via the bootloader.

 

[Larry Standage]

You have to use an external tool, such as PICkit 3, PICkit 4, Snap, ICD 3, ICD 4, or Digilent PGM. These can be used with the MPLAB X IDE to load the bootloader and program it.

[32bits]

I now find Mikroelectronica has a small PC application https://www.mikroe.com/mikrobootloader 

and this can talk to the MAX32 by adding a few components and USB socket and connecting to the builtin USB of the PIC32MX 795 using pins 54 for VBUS, 56 for D- and 57 for D+

a BAT43 and three resistors are needed. The bootloader to program the PIC32 can be found at https://download.mikroe.com/setups/programming-software/mikroprog/pic-dspic-pic32/mikroprog-suite-pic-dspic-pic32-programming-software-setup-v270.zip 

once loaded via a PIC32 programmer the bootloader works very simply with the above PC application to load the hex file from your chosen compliler.

[Larry Standage]

Sorry, I misread your original question.

There is pic32prog, which can communicate with the chipKIT bootloader on the MAX32 to load applications.

https://github.com/sergev/pic32prog

 

[32bits]

Thanks Larry, I will check out the Pic32prog application, if this works with the Max32 via the built in USB port it will save making hardware changes to the Max32 board. Are there any instructions or notes for using Pic32prog with a Max32?

[Larry Standage]

I don't know if there is a bootloader specifically for the MAX32 that goes through the physical USB, rather than the USB-to-UART chip. However, there are some USB based bootloaders for other boards available.

https://github.com/chipKIT32/chipKIT-digiboot

On that one, look for 32MX7 USB hex files. The LEDs probably won't work, but you should be able to communicate through USB.

https://github.com/chipKIT32/PIC32-avrdude-bootloader

This one has a bootloader project, so you could build one specifically for the MAX32 via USB. But there are hex files for the Fubarino SD, and the UBW_MX795_USB.hex that might work.

[32bits]

Thanks for the bootloader download locations I will try these. I checked out Pic32prog and this looks to be a command line application, is there a stand-alone PC application which has a graphical front end which can communicate with the Max32 bootloader via the Max32 FTDI chip and associated USB? Or is there a guide to using Pic32prog?

[Larry Standage]

I'm not aware of a GUI offhand, but I did find this download that is supposed to be a front end for pic32prog. Haven't tried it myself.

https://www.rictech.nz/pages/8/Downloads

 

[32bits]

I tried the front end GUI for Pic32prog, it seems to recognise the Max32 but fails to make any file transfer, I suspect I have the wrong bootloader or the bootloader needs a script change.

The main reason for looking for a bootloader is to place my Max32 project remotely so a friend can update the code without using a PIC32 programmer, for this reason operation has to be very simple.

As a quick fix I have added a USB socket and connected this direct to the PIC32 HID pins, (VBUS 54, D- 26, D+ 27 and 0v) , both the D+ and D- have 27 Ohm resistors in series with the leads to the PIC32, the VBUS has a 270 ohm resistor and BAT32 low forward volt drop diode in line. After programming the PIC32 with Mikro's HID bootloader code and then using their PC bootloader application it worked first time. The PC bootloader app is very intuitive as it recognises the PIC32 bootloader and give clear indication for connection, hex file selection and upload. The speed of upload to the Max32 is very fast, in fact faster than my main programmer. The only other thing I had to do was to cut the PCB trace under JP5 to isolate the Max32 FDTI chip.

[Larry Standage]

Sounds like you've got a pretty good solution. The only thing you'll have to be aware of is that you might need a different linker script to correctly load with Mikro's bootloader.

[32bits]

Hi Larry,

The bootloader is for the same PIC32MX 795 processor as fitted to the Max32 so I think this is why no scrpt change is needed. My code is now 700Kb is size and this loads in a few seconds, its actually faster than my programmer. Thank you for your help and suggestions.