Honored Contributor
Honored ContributorHi,
well the VCCA is why the slogan "you need just two voltages for the FPGA" some time ago is not valid when you have to interface with 3.3V logic... I struggled once on this "you need to connect VCCA to 2.5V" also on my first Cyclone II board... While I have currently no clue for the nStatus (assuming there is only the FPGA and the Pull-Up on the line) the "wrong" identification on JTAG is ok... Strange enough the ID reported by the Cyclone IV and III are identical thus the "Auto detect" reports a Cyclone IV as a Cyclone III - you have to correct this to proceed with JTAG configuration... Referring to ohmic measurements on FPGA pins - be careful when you are using a standard DMM - ohmic measurements are taken (normally) by application of voltage and measurement of currents.. If the DMM applies a measurement voltage above 3.3V, this will either result in internal clamping diodes on the FPGA (which are normally not active w/o being configured) or other I/O structure to get conductive... Sometimes with predamaging the I/O structure - just as a hint... Nevertheless there is something tying TDI to GND (most likely the Blaster - are there not even some pulses? E.g. on "Auto-Detect"?) Carlhermann
