On Tue, Jun 19, 2001 at 05:46:43PM +0200, Ronnie Arosa wrote:
> I'm working with an Oxsemi's chipset. I've got a development board and I
> would like to test the chip it incorporates.
Well, ppdev isn't really for this sort of thing: it's for writing
device drivers for peripherals really.
I would suggest that for this debugging need you should just do an
inb() on the right I/O address in user space (write a small ioperm
program, or use /dev/port).
> The development board was
> not correctly integrated and designers have forgot some pull-up
> resistences need to work in some modes (mode compatible for example). So
> instead of just siiting down waiting for receiving the new board, I
> would like to start testing with the modes that the chip is supposed to
> work. I've changed parport_pc.c to input the ECP mode to the ECR
> register at initialization time. But after initialization ECR returns to
> PS2 mode, incomprensiblemente.
I think that the ECR gets reset to a 'normal' value more often than
necessary in parport_pc. I have an item on my todo list reminding me
to look at it, but I haven't yet. This sounds like it might be
causing your problem.
I'm pretty sure that there is a debugging function now in parport_pc
for dumping the state of the registers: dump_parport_state (in
parport_pc.h). Can you use that to help track down what's going on?
Tim.
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