Is the nCONFIG pin on the MAX 10 (10M02SCE144) input only?

[GAlm0]

We are having a dispute here whether we must drive the nCONFIG pin with a open drain gate (together with a pull-up to VCCIO) or if we can use a push-pull driver (without any pull). Some of us thinks the documentation in some places can be interpreted as if the nCONFIG pin also can be an output while I personally beleive it will always be an input, during both configuration and in user mode.

[AnandRaj_S_Intel]

Hi Gunnar,

 Yes, nCONFIG pin is input only during user mode.

Upon power-up, the nCONFIG pin must be pulled high. Connect this pin directly or through a 10-kΩ resistor to VCCIO.

check section 2.3.2 from below link also refer pin connection guidelines.

https://www.intel.com/content/dam/www/programmable/us/en/pdfs/literature/hb/max-10/ug_m10_config.pdf

https://www.intel.com/content/dam/www/programmable/us/en/pdfs/literature/dp/max-10/pcg-01018.pdf

Regards

Anand

[GAlm0]

Hi Anand, Thanks for your reply and pardon me for reacting so slow! I need to ask more about this as we still don’t know if the nCONFIG pin are input only or bidirectional. You answered that it is input only in user mode (I agree on that) but we can still find information in the documents you refer to that can be interpreted as if the nCONFIG pin is bidirectional. Please find two enclosed screenshots from the documents you pointed out to us. In the “Capture_Intel_pcg-01018.jpg” screenshot of page 7: * The table says the nCONFIG pin is an “Input, I/O”. As we know that it is input only when in user mode one can therefore think it is I/O (input and/or output) in configuration mode. * The Connection guideline says “connect directly or through a pull-up resistor to VCC”. Connecting directly to VCC hints the nCONFIG pin is never an output going low. In the “Capture_Intel_ug_m10_config.jpg” screenshot of Figure 10 (chapter 2.3.1) on page 28: * After the “Read ICB Settings” box it says “nSTATUS and nCONFIG released high”. This can be interpreted as nSTATUS and nCFONFIG pins are both bidirectional because we know that nSTATUS is bidirectional. So, can you please answer these two questions: * Is the nCONFIG pin always an input or can it ever be an output? * Is the nCONFIG pin ok to drive with a regular totem-pole output gate? Sorry for being so stupid. Regards, /Gunnar Alm

[AnandRaj_S_Intel]

​Is the nCONFIG pin always an input or can it ever be an output?

>> During user mode, the nCONFIG pin is Input only. Can not be output under user mode.

Is the nCONFIG pin ok to drive with a regular totem-pole output gate?

>> What exactly you trying to do??

[GAlm0]

I want to drive the nCONFIG pin with a regular totem-pole gate such as 74LVC00. /Gunnar

[AnandRaj_S_Intel]

​Yes, we can use.