Hi group,
My design contains 1 MAXII EPM1270, 1 LXT971, 1 LXT971, 1 MAXII EPM1270 in series in a JTAG chain.
Of course, I defined an element called LXT971 with an instruction register length of 4 (as stated by the manufacturer). Strangely however, using the "Auto Detect" feature, Quartus sees both EPM1270 all right and two "unknowns" in the middle with an instruction register length Of 16 (!!!).
The QUARTUS II software keeps on misbehaving since a few days. I think the misbehaviour is related to the installation of version 5.0 SP1 (Web version) and/or a recent version of the LPT1 driver for the ByteBlasterMV/ByteBlasterII.
Before that, I had no problem at all for downloading both EPM1270's (with the MV pod only. I always had problems with the II pod).
Now, whatever the programming adapter, if I try to do any operation on the second EPM1270 of the chain (4th device of the chain), I get a curious message like :
Error: Can't recognize silicon ID for device 4 Error: Operation failed
But, any operation on the first device always completes successfully.
So, the problem is probably due to the presence of the two LXT971 in the center of the chain (although everything worked fine and reliably with the MV pod and previous software/LPT driver)?
I remember I had an equivalent problem with the Xilinx ISE tool (defining the JTAG instruction register length was not sufficient to make the thing work. I had to provide the full BSDL file to ISE, and from there on it worked).
BUT, I see no such thing in the Quartus software, just the instruction register length may be entered.
Any idea please.