Hi, thanks for your answer.
On Tue, May 28, 2013 at 4:41 PM, Jagan Teki <[email protected]>wrote: > HI, > > Few little comments. > CCed driver contributed delegate, may be they will help if I am > missing any thing. > > On Tue, May 28, 2013 at 6:48 PM, laurent vaudoit > <[email protected]> wrote: > > Hello all, > > > > i have integrated soft_spi driver in u-boot, in order to communicate > with a > > FRAM device, using some GPIO. > > > > I use mode 0 of spi (CPHA=0, CPOL=0). > > > > When i try to communicate with the device, i have a problem, none of my > > commands are answered. > > Giving to an understnding how does it works, ignore if you know it already. > > usually we have give an mode bit as 0, so the mode bit will check at > driver level to get any change on > clock phase and polarity level(CPHA and CPOL) > > u-boot> sf probe 0 0 0 > last argument assigns the global mode variable. > > You checked with mode 0 or 1? > > What exactly the issue log, means where it goes wrong? > Does it on spi_xfer?, or spi_claim_bus? > > My problem is on sspi_xfer function for testing i use command sspi 0 (chip select) size data i have ss->mode to 0 (so CPHA and CPOL is 0) When i look at the code, i have: if (!cpha) SPI_SCL(!cpol); My problem is this line SPI_SDA(tmpdout & 0x80); SPI_DELAY; if (cpha) SPI_SCL(!cpol); else SPI_SCL(cpol); tmpdin <<= 1; tmpdin |= SPI_READ; tmpdout <<= 1; SPI_DELAY; if (cpha) SPI_SCL(cpol); > > > > After looking signals with scope, i see that if CPHA and CPOL are 0, > > there is a rising edge on the clock signal, before data is set on mosi > > signal. > > > > So the device get a first byte in an "unknown state". > > > > looking at the code, we can see that if CPHA is 0, we put a rising edge > on > > clock before any data management. > > > > I made work the communication by forcing CPHA to 1 but i think it is not > > good way. > > What you made by default the CPHA is 0x1, did you make change on the > spi_xfer? > yes for testing, i force local variable cpha to 1 in spi_xfer. I hope i'm clear, thanks Laurent > > > Thanks, > Jagan. > > > > > Is there something i don't understand? > > > > thank you in advance for your answer. > > > > Regards > > > > Laurent Vaudoit > > > > _______________________________________________ > > U-Boot mailing list > > [email protected] > > http://lists.denx.de/mailman/listinfo/u-boot >
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