On 5/23/2011 6:19 AM, Wolfgang Denk wrote: > Dear Graeme Russ, <snip> > This is what PPC is doing. And I understand that Reinhard did the same > in software for AT91. Hi All, My apologies for being a little (perhaps more than a little) dense. As they say, "after further review", I think the key aspect of the PPC timer system is that it uses the decrementer register to generate an interrupt at a 1 KHz rate. What I have been attempting here is to produce a timer system that does not use interrupts at all. This is a fundamental design question. Naturally, systems that can generate an interrupt at a 1 KHz rate (or at any (reasonable) higher rate for that matter) using the decrementer register can produce a 1 ms resolution software counter that updates "by magic". If my understanding of this PPC code is incorrect, somebody please stop me before I make a further fool of myself! Is it then a design requirement that the timer system use interrupts? Is that what is meant by using the PPC system as a model? If so, is it possible/reasonable on all the u-boots that are out there to generate and process timer interrupts at some (hopefully but not necessarily) programmable rate?
Best Regards, Bill Campbell > Best regards, > > Wolfgang Denk > _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot