On Thu, 13 Jan 2005, Eric Smith wrote: > > Kolja wrote: > > There is a HAL that allows to efficiently send large blocks of data via > > JTAG > > http://www-ee.eng.hawaii.edu/~linbai/Java_API/java_native_interface.htm > > I wrote: > > That's a much better interface, since you can supply an arbitrary amount > > of data in one call. > > Kolja wrote: > > Unfortunately there are no API documents on that page. But the HAL is > > designed for the API, so there must be > > API suport for transferring large blocks of data, even if Xilinx doesn't > > use it in the example. > > Huh? Most of that page *is* API documentation. I was specifically > referring to the interface: > > public native byte OperateTAP( int bitCount, byte[] TCKbits, > byte[] TMSbits, byte[] TDIbits, byte[] TDObits ); > > which is described in considerable detail. > > The rest of the API is not too different than the other bit-at-a-time > one, but that one OperateTAP call makes it possible to do reasonably > efficient remote JTAG for some things. > > It may still be insufficient, though, because for some devices it may > not be possible to blindly send large blocks of data without examining > the feedback until the entire block completes. > > For instance, if you want to program a parallel flash memory device > attached to pins that can be controlled by a JTAG scan chain, you > want much more of the smarts to be near the device, because you have > to shift the entire scan chain every time you change any signal. If the hardware designer is nice and brings out the CS, OE, and WE pins, you can save quite a few scan chain shifts. The SVF file format supports messing with IO bits to do this. > > Eric > > To post a message, send it to: > To unsubscribe, send a blank message to: > Yahoo! Groups Links > > Peter Wallace Mesa Electronics |