Help with programming UC3B microcontroller / JTAG

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I've made a board with a UC3B0128 microcontroller, but I'm having problems programming it. According to this document, there was supposed to be a USB bootloader preprogrammed on the microcontroller, but mine does not seem to boot into it. There is no activity on the USB pins on the uC or on the 12MHz crystal connected to it, and I've checked this on an oscilloscope. It does seem to be receiving power though, since the reset pin is set high through an internal pullup, TCK, TDI, and TMS are high, and all power pins have the proper voltage on them.

 

I'm thinking there just isn't a bootloader, or it doesn't initialize properly for some reason. If that's the case, I'm going to have to program it with JTAG. So my question is, if there's nothing I'm missing with the bootloader, what's the easiest way to make my own JTAG programmer? I really want to avoid buying one just to use it once. I want to use an arduino to do this, so is there code that already exists and works with programming this chip? I've seen this, but I'm not sure if it would work with my situation, and if I should look into it more.

 

Thanks for any help!

Last Edited: Sun. Apr 2, 2017 - 06:19 AM
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Preface : I haven't actually used the pre-programmed bootloader.
In that Atmel doc7745.pdf there is a section which describes the bootloader configuration.
For the UC3Bxxx the 0x929E0D6B configuration decodes to ;
bit 16 : 0 = active-low level on the condition pin.
bits 15-8 : condition pin is 0x0D = GPIO 13 (PA13)
Via a resistor (eg. around 1k ohms), try pulling PA13 low during the reset/power-up.


Have a look at the Programming and Debugging section of the datasheet, and see if you want to make your own, or buy, a JTAG programmer :)

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I've tried that, it doesn't seem to work unfortunately.

 

And the datasheet says very little about how programming works, so I'm hoping there's some JTAG device clone for arduino already made.

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On the UC3C-EK dev board, which is a different chip, you have to have a button pressed while booting it to enter the bootloader. I spent a few hours with it and only got it working with CLI tools -- programming from a GUI just didn't work.

 

But I think you need a JTAG debugger anyway, because of debugging.

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It looks like that board has an actual microcontroller to program the uc3c (with JTAG), which is pretty different than this.

Anyways, another question, will I need one of the JTAG devices listed by Atmel studio to program it, or will any JTAG avr device work?