FPGA Configuration Problem

[Altera_Forum]

A strange one here. I'm trying to power up a Cyclone III EP3C10 in active serial mode, and even before the device tries to access the PROM it drives all I/O pins low and does not make any attempt at external access. 

 The 1.2, 2.5, and 3.3 V supplies all rise monotonically within 5 mS of each other, all the right pins are connected to all the right voltages, but the only activity I see is that the nConfig and Init_Done lines rise to about 2V while the device is powering up, and then they go to ground. nStatus, Conf_Done, and all other lines never go high.  I want to blame the chip, but we've installed 2 chips on 2 boards, and we're seeing the same problem. Unfortunately, we don't have any known good designs we can use to test out the chip.  Any ideas? Thanks.

[Altera_Forum]

If it's an EQFP144 device, did you connect the enhanced pad to GND?

[Altera_Forum]

What are your MSEL pins set to? 

 Jake

[Altera_Forum]

And how are the MSEL pins wired?

[Altera_Forum]

--- Quote Start ---  If it's an EQFP144 device, did you connect the enhanced pad to GND?  --- Quote End ---   I just saw that pad. No, it is not grounded, but I can set that up pretty easily. Altera really doesn't draw enough attention to that pad if not connecting it can kill the entire part.    --- Quote Start ---  What are your MSEL pins set to?  Jake  --- Quote End ---      --- Quote Start ---  And how are the MSEL pins wired?  --- Quote End ---   MSEL[2:0] is 010, and the lines are tied direct to GND or +2.5

[Altera_Forum]

--- Quote Start ---  Altera really doesn't draw enough attention to that pad  --- Quote End ---   The fact, that this issue is a series topic in the forum seems to confirm your statement. I found the "exposed pad" thing mentioned in two places in the device manual and also in the Device Pin-Out document. The amount of informations hasn't changed from Device Manual V1.0 to recent V2.1.  You may want to read a ceterum censeo "Furthermore, don't forget to connect the exposed pad" in each Handbook chapter.

[Altera_Forum]

Yes, the hidden ground pad just needed to be grounded. The board is now powering up normally. 

That pad should really be listed as a pin in the pinout document, not as a footnote. It seems to be rather important.