On Thu, 2011-03-31 at 14:32 +0800, Xiangfu Liu wrote: > cable milkymist > detect > (I maybe can guess those two commands do) > instruction CFG_OUT 000100 BYPASS > instruction CFG_IN 000101 BYPASS > (what are those two doing??
Define addresses for the CFG_IN and CFG_OUT JTAG registers of the FPGA, which are needed to read and write the bitstream from/to. For some reason, Michael left them out from the FPGA definition files - if it is possible to add them there so these commands become unnecessary, feel free to do so and send a patch to the UrJTAG list. > pld load fjmem.bit > (send fjmem.bit to fpga?, what fjmem doing after load?) FJMEM creates a smaller boundary scan chain with only the pins needed for the flash, so you don't have to scan several hundreds of I/O pins every time you need to change or read a single bit related to the flash. It makes flashing much faster. > initbus fjmem opcode=000010 Tells UrJTAG that a FJMEM core is present and how to address it. > frequency 6000000 > (don't understand) This reduces the frequency of the JTAG clock, IIRC so we do not overclock the flash. OTOH, writing the flash from RTEMS is still faster than through JTAG, so I think this frequency could be increased a bit. S. _______________________________________________ http://lists.milkymist.org/listinfo.cgi/devel-milkymist.org IRC: #milkymist@Freenode Twitter: www.twitter.com/milkymistvj Ideas? http://milkymist.uservoice.com
