On 03/21/2013 05:19 PM, Laurent Gauch wrote: > Le 21.03.2013 17:03, Salvador Arroyo a écrit : >> On 03/21/2013 04:52 PM, Laurent Gauch wrote: >>> Le 21.03.2013 16:41, Salvador Arroyo a écrit : >>>>> But the num_cycles will be depending on the frequency of the JTAG >>>>> interface. >>>> Of course. >>>>> Are there any bit to check when scanning the target jtag register, >>>>> to know if the data is valid or not? >>>>> Laurent >>>> Each fastdata scan is 33 bits wide. The first bit scanned out, >>>> spracc bit, indicates if the transfer was successfull or not. >>>> The problem is that most of us use ftdi based adapters. If we check >>>> every scan the resulting transfer speed is really 16/4K at most. >>>> Current code queue all the transfer and execute it, without any wait >>>> between scans. This works up to some scan rate, but is enough to get >>>> a transfer rate of 100K.(at least for pic32mx at 8Mhz). >>>> Adding a little delay between scans with jtag_add_clocks(), transfer >>>> rates of 500K are easy to reach, at least for pic32mx at 8Mhz and a >>>> scan rate of 15000Khz. >>>> >>>> Thanks >>>> Salvador. >>> how much clocks for a scan rate of 15Mhz ? >>> >>> Regards, >>> Laurent >> 20 >> >> But if the wait 0 option for ram access is set, with 17 probably works. >> >> Thanks >> Salvador >> >> > Thank Salvador, > > if we up the jtag frequency to 30MHz or 60MHz (for a mips supporting so > high JTAG frequency), does the number cycle will be 40 or 80 ? Not necessarily
The same pic clocked at 4Mhz needs 40, and of course the transfer speed is lower. Clocked at 80Mhz does not need any delay and can transfer over 800kbytes/s at the same scan rate (15000khz). Thanks Salvador ------------------------------------------------------------------------------ Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_d2d_mar _______________________________________________ OpenOCD-devel mailing list OpenOCD-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/openocd-devel
