Program CPLD from Cyclone IV on BeMicro board

Hi Don,

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I want to program a MAX V CPLD _through_ the Cyclone IV on the BeMicro SDK board. On a ground-up design you would insert the CPLD in the JTAG chain with the FPGA, but I don't want to hack the BeMicro hardware, and don't see a way to do this without some creative soldering. (?)

So what I want to try is hooking the CPLD JTAG lines to the FPGA's GPIO lines.

PC <--JTAG--> FPGA <--GPIO--/--JTAG--> CPLD

But it's unclear what to instantiate within the FPGA to make the connection... if I had access to the JTAG lines, it would be pretty simple... Can this be accomplished with the Virtual JTAG or other JTAG-related megafunction? Is the whole idea misguided?

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The Virtual JTAG interface can be used for the communication from the host component of this design, but unfortunately Quartus will not recognize this sequence of hardware as a JTAG chain, so you won't see your device in the programmer.

I have used the Jam STAPL programmer to implement this type of interface. Basically you provide toggle callbacks for TCK/TMS/TDI/TDO. In this scheme you would have a Virtual JTAG or JTAG-to-Avalon-MM bridge component in your BeMicro and treat it like a GPIO board.

You could buy a Terasic USB-Blaster for $50.

Or if you are up for a challenge, you can buy the BEMICRO-PROTO board, an FTDI FT245R module (UM245R), solder that to a header on the BEMICRO-PROTO board, and then build your own USB-Blaster logic in the BeMicro (and the FT245 EEPROM) ... for probably around $50 plus your time.

Cheers,

Dave