Jason: there's where I am not fully comprehending this whole jtag thing.
it seems to me that some arm chips (lpc for example) have internal bootloader that once up on reset can receive data on its own. so why do we need such an expensive device?
also, some of the schematics I have seen about jtag seems to suggest that it is taking signals from a db25 connector (rst, tms, tdi, tdo and tck), buffer them through a dual 232 chip and then dump them onto the same pins on the chip, with the rst signal reversed. that doesn't seem to be too difficult to wire up by oneself; and why do they need that buffering (for speed?)? so it seems to me the simplest thing would be to wire everything straight and then invert the rst signal (with a transistor). or if you are really cheap, program a dip8 pic to buffer it.
then there seems to be some compatibility issues as to certain cables are compatible with certain chips but not others so I am not sure where to begin.