Steven Hirsch wrote:
Do I connect to the Digilent cable to the SOFT or the HARD pins or both?Definitely not both. I believe it would be the HARD set, but don't take my word for it! I'd much like Alex or Steve to explain the distinction and uses of hard vs. soft JTAG.
Correct. The "hard" JTAG is the real JTAG. The "soft" JTAG is used by Altium Designer tools to talk to soft instruments inside the FPGA. As we are not currently using AD, the "soft JTAG" pins are free for other use. The default configuration uses two as 3.3V level serial port. NOT to be connected to RS232 which is +/-12V.
Also the CB schematic shows the CONNECT pin as VREF (whatever that is). It also says "IF YOU ARE CONNECTING THIS INTERFACE TO USER BOARD A OR USER BOARD B DO NOT CONNECT THE REF PIN. REFER TO THE APPLELOGIC WEBSITE FOR DETAILS". Unfortunately, the Applelogic website seems to be down. So before I fry my CB card can anyone give me a heads-up on what to do?That's definitely a Steve-or-Alex question...
The JTAG connector on the CB was designed to be AD compatible. The CONNECT pin is used to let the rest of the system know that something is plugged in. This is not needed using non-Altium tools but other cables require a voltage reference. Note that Digilent cable says something like "1.8 to 5V". It needs to know which voltage to use. The VREF is used for that. So CB design was modified to rewire the unneeded CONNECT as a voltage reference for the non-Altium JTAG cables.
-Alex.