Is USB OTG required for flashing microcontroller memory?

Hey guys,


Quick question. I want to be able to reprogram my microcontroller through my smartphone. My microcontroller will be sending data to the phone through USB with a built-in USB module. However, I will run into the problem of wanting to update my firmware without changing the unit completely.

If I were to send a .hex file through USB, would I need to have USB OTG capabilities to re-program my microcontroller?

Can I get away with just a USB slave device to send data, and be reprogrammed through it?

I am hoping to use just the PIC18F45J50 to get this done. However, it only has full-speed USB device capabilities.

The other one I'm looking at is the PIC24FJ32GB004.

Can I update the firmware of PIC18F45J50 with just that chip by sending it a .hex file with a smartphone?

If not, could the PIC24FJ32GB004 be what I'm looking for?


An example would be the Arduino Uno. It uses an ATMega8u2 as a FTDI chip to communicate with the computer, and I'm assuming this is the device that flashes the ATMega328's memory. The smartphone is able to read data accurately from the Uno through Physicaloid.

The Arduino Micro uses an ATMega32u4, which has a built in USB module. It is able to be reprogrammed and is supported in the Arduino IDE as well. However, when using the Micro to communicate with the smartphone, it only sends the phone garbage data. Is there a workaround for this?

If you want to update your firmware only with smart phone, than you can do it without the need of having USB OTG, by using USB-HID Bootloaders.

I had seen USB HID Boot-Loaders fro Microchip PIC 8-bit series of controller's, but you have to write the smartphone application by your own.
USB OTG is not required in this case, but if you want to update your code from a Pen Drive, then you need a HOST or OTG device.