I have an Altera CPLD, 5M570ZT100I5N (100 pins, Quad-Flat-Package) mounted in a socket adapter to get access to the pins. I try to beep two GND pins on the same edge of the package, but get no response. Is this an indicator that something is wrong with my socket adapter ? BTW, the CPLD is not programmed, nor has any power connected to it. I would still expect any two GND pins on the same IO-bank to be connected. Am I wrong ?

  • \$\begingroup\$ what is beep? \$\endgroup\$ – jsotola Mar 13 at 23:04
  • \$\begingroup\$ @jsotola Continuity test. \$\endgroup\$ – ScienceGeyser Mar 13 at 23:07
  • \$\begingroup\$ continuity test using what kind of a device? \$\endgroup\$ – jsotola Mar 13 at 23:27
  • \$\begingroup\$ multimeter buzzer \$\endgroup\$ – Ronny Landsverk Mar 14 at 0:15

Many chips do not have internally connected GND pins. This is frequently done in order to allow a separate analog and digital ground and to allow decoupling isolation. The same is true on VDDs as well.

  • \$\begingroup\$ Why does Altera not document this? \$\endgroup\$ – Tony Stewart EE75 Mar 14 at 7:51

Is this an indicator that something is wrong with my socket adapter

probably, YES. are any other pins open?

Interesting but hopefully not relevant...

Programmable Ground Pins

Each unused I/O pin on MAX V devices can be used as an additional ground pin. This programmable ground feature does not require the use of the associated LEs in the device. In the Quartus II software, unused pins can be set as programmable GND on a global default basis or they can be individually assigned. Unused pins also have the option of being set as tri-stated input pins.

From the Altera (now Intel) MAX V Device Handbook


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