I am considering selling the extra boards that I have right now. I have
15 boards that I have not soldered on, etc. I am thinking about selling
these boards for $40 (fully assembled and tested). If you wanted the
programmer board with a cable, that would probably be another $10. I
haven't been able to successfully write a programmer program because my
parallel port is messed up. I have one I think works, but I would have
to either get another parallel port (not too expensive) or else let
somebody else try it. If anyone would be interested in purchasing a
board, I plan on burning in a bootloader program previous to shipping
the board, which uses the RS-232 port to upload user programs. Please
leave comments if you'd be interested in a board so I can gauge
response to see if it's worth ordering the extra parts.The on-chip
bootloader is written in assembly (yuck) and lives in the highest page
of flash (starts at address 0x3E00). It uses the UART to communicate to
the program that was written for the PC in C# to get its data. The
program was written with the potential to be expanded, but that
framework hasn't been developed yet in order to get it done quickly.
The only rub with using the bootloader is that, unless you can time
hitting the RESET button really well, you need to add a green-wire fix
to allow the RTS line from the RS-232 port to control the RESET pin on
the nRF24LU1. This is relatively easy, and I will put up a schematic
and pictures if anybody were to need it.On-Chip BootloaderThe
bootloader was written to be compiled with AS31, which can be
downloaded (with a special version of SDCC) here. The link to the .zip
file containing the makefile, asm source file, and compiled hex file
can be found here.PC-Side BootloaderThe bootloader program on the
PC-side was written in C# for Windows (Linux guys are on their own).
This version was written with Visual Studio 2005 Professional, but it
can also be compiled using Visual C# 2008 Express, which is a free
download from here. The link to the .zip file containing the C#
project, source files, and executable file can be found here.

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Posted By brennen to diyembedded.com at 5/14/2008 08:46:00 PM