USB Bootloader.

[ardhuru]

Thanks Dave,
I got the 'other' USB bootloader from Microchip working (I believe it is the HID bootloader), well kind of.... I have a simple blink-a-led program that when flashed directly to the PIC works fine but when downloaded thru the bootloader it either doesn't "get there" or it never executes or there's something else going wrong.

Thanks!
/Henrik.

Absolutely the same problem here, Henrik. Did you make any progress?

Moreover, I find that all the USB bootloaders at Microchip, by default use a setting of HS Oscillator, PLL enabled, HS used by USB; with this I always get a USB Device Not Recognized; I have to change it to HS Oscillator, HS used by USB to get the pic (18F4455 in my case) to be recognised by the PC. But beyond this point, the loader fails to 'burn' the program in the pic; I have used the DEFINE LOADER_USED 1 and DEFINE RESET_ORG 1000h.

Wonder what I am doing wrong?

Incidentally, the test program works despite the 2 defines if I program it directly using a Pickit2. Didnt really expect that to happen?

Regards,

Anand

[HenrikOlsson]

Hi,
Sorry, no progress, I gave up on it for the time being. Still interested if you or anyone else has or finds a USB bootloader that "just works! though.

/Henrik.

[ScaleRobotics]

Did you guys see this thread:
http://www.picbasic.co.uk/forum/show...usb+bootloader

It talks about skipping over the bootloader code using:

DEFINE LOADER_USED 1
DEFINE RESET_ORG 1000h ' For Microchip USB Bootloader

Just wondering if that improves anything? Have yet to try the USB bootloader here though.

[ardhuru]

First, thanks Scaler for the reference; I had included the 2 defines.

Now, to sum up my observations; Henrik, these might be of use to you.

1) A 10uF cap across the Vdd, Vss seems mandatory, regardless of whether you're powering up from the USB, or a separate supply.

2) The Microchip HID bootloader works all right, although it gives a program/verify error. Once you program your code thru' the bootloader, you need to *re-start* the pic; a reset doesnt help. At this point, when the pic comes up again, your code will start executing happily.

3) To get back into the booltoad mode, momentarily ground RA6. You're now ready to load another file thru' the bootloader.

Not perfect, of course, I'd still like to not have the bootloader report the error, but seems to work otherwise.

At times I feel like just giving in favour of a serial bootloader but the concept of a USB bootloader is too tempting to go away

If anybody does any further work on this, or wishes to add more, I'd really appreciate it.

Regards,

Anand

[ScaleRobotics]

Sorry Anand, missed that you already tried that. I got a chance to try out Microchip HID Bootloader v2.3 this morning on a 18f4550 using the Olimex PIC-USB-STK http://www.olimex.com/dev/pdf/PIC/PIC-USB-STK.pdf

and I got an LED blinky to work. For this chip, you have to hold down PORTB.4 to get it into bootloader mode. Then I can program and verify correctly. The hex I was using assumes a 12 mhz oscillator, and uses PLL to bring it up to 48.

Once my blinky program is loaded, I can hit the reset button, and my LED starts to blink.

[ardhuru]

For this chip, you have to hold down PORTB.4 to get it into bootloader mode. Then I can program and verify correctly. The hex I was using assumes a 12 mhz oscillator, and uses PLL to bring it up to 48.

Once my blinky program is loaded, I can hit the reset button, and my LED starts to blink.

Thanks a ton! Wasnt aware of the PORTB.4 switch, works perfect.

Now, if I can just figure out why I get the error message, despite the code getting programmed alright!

BTW, what hex file are you using for the bootloader? And, the Olimex schematic shows a 20 MHz crystal (the same as mine); how did you change the hex file to accomodate the 12 MHz?

Thanks for the help!

Anand

[ScaleRobotics]

Glad to hear it almost works for you. What error message are you getting? Is it on verification? Are you changing any of the configs for the program you are trying to bootload?

As far as my crystall, Hmmm....

My eyes are getting bad.... Will have to check the board again when I get home. I have not changed the crystall, so it is just a matter of whether it matches the schematic. I will attach the hex file I am using tonight as well. But I think it came with Microchips MCHPFSUSB Framework install (79 meg download). I did not modify it, just programmed it directly.

Walter

Added:
Here is some more information about their bootloader. This is included in the large downlaod, but you sort of have to search for it.

http://www.scalerobotics.com/MCBootloader.html