Chaves, Kevin wrote: > Hi, > > So I've been working with an FT2232H chip for about a week now, and libftdi= > for 2 days. We had an issue with the libMPSSE_spi with linux so I decided = > to switch to libftdi. I grabbed some source code for using the chip in spi = > master mode.
What code? From where? Why are you asking libftdi authors instead of the authors of that code? > We have two really small issues and I'm wondering if there is a way to conf= > igure the library to clean up.=20 > > 1. Clock signal=20 > I think I'm screwed with this one, since its a clock divisor. We need 8Mhz = > but it seems to jump between 7.5 and 10, going from 7000000 and 8000000 as = > inputs. I'm guessing I might be able to get it closer but hitting 8 might n= > ot be possible. That matches what FTDI AN-108 says. > 2. Small pauses in the clock.. > Each byte written there is a small pause before the next burst of 8, its ve= > ry very small but we aren't sure why this is happening. The libMPSSE didn't= > do this but it also didn't work beyond 50khz... so maybe it wasn't as noti= > ceable there. How small is "very very small"? Since's it's synchronous, it shouldn't matter. If you need a regular clock, maybe you could use an asynchronous mode. > 3. Large pause before read > I think i know why this is happening and there isn't much I can do about it= > . There is a long pause between writing the command and reading the data. T= > his likely is because the library I'm using is calling write then read, so = > its probably more likely having to do with the cpu cycle and driver stack t= > han it is the chip. But I could be wrong. Our spi device expects to shoot t= > he data back out immediately.=20 How long is "long pause"? -jim -- libftdi - see http://www.intra2net.com/en/developer/libftdi for details. To unsubscribe send a mail to [email protected]
