Messages in this thread | | | Date | Thu, 11 May 2006 15:15:53 +0200 | From | "Carlos Ojea Castro" <> | Subject | Re: LPC bus in a geode sc1200 |
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On 5/10/06, Lennart Sorensen <lsorense@csclub.uwaterloo.ca> wrote: > On Wed, May 10, 2006 at 09:55:47AM +0200, Carlos Ojea Castro wrote: > > Thank you very much for your reply, Len. > > I will also have an FPGA (I think it will be on port 0x1400 or so). I > > am writing to LPC using 'outb' like this: outb (data, port); > > So I see an I/O write on the LPC bus, that is: 2 bytes for address and > > 1 byte for data (it tooks one microsecond per transfer). > > > > To speed up things, I wish to transmit more than 1 byte for data in > > each transfer (if possible). > > Accordingly with page 194 of the sc1200 processor data book, it is > > also possible to do a "Bus Master Memory Write" to transmit 1,2 or 4 > > bytes. > > Do you know how can I make a "Bus Master Memory Write" to the LPC? > > Well I know we don't do that. We have very little data, just board > status information from various places on the board. LPC does support > doing DMA, which I believe is done in the same way it was done on ISA at > least as far as the software is concerned. How to implement DMA for LPC > in the FPGA I have no idea. The LPC specifications would probably tell > you. I imagine it involves setting up a DMA buffer in RAM (in the first > 16MB probably) and then sending a command to the FPGA telling it to do a > DMA transfer from that memory location using the LPC DMA commands. > > Len Sorensen
Well at this moment, using the low address byte to transmit data, I can transmit 100.000 bytes in about 63 milliseconds, maybe it is enough. Will try DMA anyway... Thank you very much!
Regards, Carlos - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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