tiny bootloader problems!!!

electrogen · Joined: 24 Feb 2009 Posts: 15 Location: Addis

I'm using the tiny bootloader. I burnt the bootloader on the PIC(18F458)
and then when I tried to load my code using the tiny bootloader PC
application it reports "pic sending unknown data: K not found ERROR!"

But according to the tiny bootloader algorithm the PIC sends 'K' after the
PIC ID, isn't it?

Anybody who had the same problem, please help?
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chips are forever

meereck · Joined: 09 Nov 2006 Posts: 173

The tiny bootloader has always worked like a charm for me.
Did you compile the tiny bootloader by yourself? Did you set correct crystal setting, frequency and UART baud rate?
How did you connect the PC and the PIC? Do you have MAX232 chip in your circuit?

electrogen · Joined: 24 Feb 2009 Posts: 15 Location: Addis

yeah, I connected everything as stated on the tinybootloader website, ofcourse the hardware connection is all provided with the zip file I downloaded. Surely no problem with the connections

I also used max232 as stated there. but I cann't figure out why the PIC sends more than one byte of ID and K afterwards.
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chips are forever

meereck · Joined: 09 Nov 2006 Posts: 173

As I wrote, check crystal and its configuration when compiling the bootloader source code.
As for serial line test (MAX232), if you didn't do so, disconnect the PIC and short RX and TX TTL pins going from the MAX chip. What you send from the computer should also be received by the computer.

electrogen · Joined: 24 Feb 2009 Posts: 15 Location: Addis

Alright, the problem is the MAX232 works only @ 5V, but I operated it @3V3.
Unfortunately I can't go up more than 3V6 bcoz I have components on board that can't tolerate a voltage more than that, otherwise I should cut the VCC line to the PIC on the PCB and supply it alone with 5V.

Thanks!
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chips are forever

Guest · Posted: Tue Mar 17, 2009 10:59 am

You can get versions of the max232 that work on 3.3 volts.

meereck · Joined: 09 Nov 2006 Posts: 173

such as MAX3232
you can also use a simple voltage divider as an input to the PIC from the MAX232 chip

vijay s · Joined: 20 Oct 2007 Posts: 17 Location: coimbatore,india

I tinyBoot loaded PIC16f877A. Actually I altered the PIC16f873A source code for 877A. Problem here is bootloader is working i.e. I am able to fuse my application, but my application code is not working. When I fuse my application code directly it's working. What might be the problem ?

I wrote my application using MPLAB 8.20, CCS 4.76.
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with regards
vijay s