2005-07-30

Note:   I found a reference to some code here:
http://www.egnite.de/pipermail/en-nut-discussion/2005-April/004209.html

It is a bootloader that uses the xmodem protocol.  It was apparently
a modification of the ethernut project bootloader.

Anyway, I modified it to mimic the intel hex bootloaders that I have
been used to using on the microchip pic parts.  Note that it reads
memory pages before it writes.  This way you don't have to erase
the flash before programming.  You just send your intel hex files...

Here is a quick overview of how it works

On boot, it will wait for around 3 seconds for the characters 'boot'
to be typed in order.  If they don't arrive in the order or fast enough,
the application code is executed.
If 'boot' is received, a '>' character will appear signaling that it 
is ready for an intel hex file to be uploaded via the UART0.  When
the end-of-file is reached, it will execute the application code.  

NOTE:  It needs about 40ms line delay @ 115,200 with 0x10 byte hex lines...

Have fun,
telliott
