Help,help!!Stratix III JTAG configuration problem

Dear all:

I have a problem when configuring the device EP3SL340H1152 with jtag. the programmer always says “Unable to scan device chain. Can’t scan JTAG chain.” while autodetecting, I test the TDI, TDO,TMS and TCK. There is data wave on TCK ,TMS and TDI, but the TDO never changed and always hold about 0 V.

Vccpgm = Vccpd = Vccio1A = 2.5V and the program connector powered by 2.5V.

nSTATUS 、nCONFIG and CONFIG_DONE are all pulled-up to Vccpgm which is 2.5V.

VVCCIO of bank 1A that TDI, TDO TCK and TMS reside is 2.5V.

However, it works well in the PS mode configuration. In addition, it is nornal for the output of all user I/Os reside in Bank 1A !

Many thanks!Best wishes to you!