Hello, I am not yet pretty familiar with 8xx system programming, so maybe you could give me some debugging hint. My C code which programs the the CPM (USB) has to execute the following commands:
eieio(); usbregs->usb_uscom = 0x80 | 0; mb(); If i put those instructions in an new function, the CPM behaves as wished, elsewise it depends on the remaining code. E.g. the number of NOP machine code instructions before make a difference: 1.) ...< remaining C function code> __asm__("nop\n\t"); eieio(); usbregs->usb_uscom = 0x80 | 0; mb(); ... <other code> 2.) ...< remaining C function code> __asm__("nop\n\t"); __asm__("nop\n\t"); eieio(); usbregs->usb_uscom = 0x80 | 0; mb(); ... <other code> Every hint howto find my mistake is appreciated! Thanks Josef