I have designed a board with a AT91SAM7S256 on it and intend to program it using the SAM-BA boot program. As I understand it, you need power, a crystal and you should be able to load a program over the serial line. Add a litlle pull-up circuit and choose the right crystal and it can be done through USB.
I have used the SAM7S-EK and that works fine, serial and USB. But my own boards sometimes works and sometimes not. If using USB, in some cases the PC sees the board immediately after powerup, sometimes it may take a very long time (minutes). The same behaviour is observed when using the serial connection. The oscilator is running fine.
When I (finally) have my own software loaded, this will always start immediately.
I've measured and scoped the power lines, osc, reset, tst, erase, but have seen nothing out of the ordinary. Schematic is the same as the EK with respect to the boot loader part.
Any suggestions or simular experiences here?
I've already mailed our FAE, but he has forwarded my question to Rouset, hope they get back to me soon.