About VCCIO, VCCPGM, VCCPD for Configuration , genernal I/O pins at same bank

Altera_Forum · ‎09-07-2015

I am going to use Cyclone V, 5CGXBC5C6F23 for my project.

I am going to use the pins of Bank 3A for 1.8V I/O signals.

I am going to use ASx4 configuration mode for configuration.

In the Bank 3A, there are configuration pins such as DATA0 ~ DATA3, DCLK, nCS.

Also in bank 3A, there are JTAG pins such as TMS, TDI, TDO, TCK.

So I am going to use 1.8V for VCCIO, 3.3V for VCCPGM, 2.5V for VCCPD.

In Assignment ---> Device ---> Device and Pin Options ,

There is option of "Force VCCIO to be compatible with configuration I/O voltage"

When I check on this option, I got error message at FPGA implementation about "mismatching of the voltage level of VCCIO and VCCPGM".

When I check off this option, I got no error message at FPGA implementation.

Can I use 1.8V for VCCIO at the bank 3A ?

Altera_Forum · ‎09-08-2015

Hi,

If I remember it correctly, the VCCPGM need to be same as VCCIO used for the particular bank.

Altera_Forum · ‎09-09-2015

That sounds exactly right to me. If you're trying to 'Force VCCIO to be compatible with configuration I/O voltage' then yes, the voltage on VCCIO will need to match that of VCCPGM. However, without that requirement, it won't.

Refer to page 18 of the cyclone® v device family pin connection guidelines (https://www.altera.com/content/dam/altera-www/global/en_us/pdfs/literature/dp/cyclone-v/pcg-01014.pdf). This specifies the requirements for VCCPGM & VCCPD pretty clearly. In respect of the VCCPGM pins it states:

--- Quote Start ---

When these pins have the same voltage requirements as VCCIO and VCCPD, they may be tied to the same regulator.

--- Quote End ---

However, if they have different requirements, they need not.

So, yes. You should be able to power bank 3A from 1.8V.

Cheers,

Alex

PS. Just to add - and confirm - I can put a project together with VCCPGM @ 3.3V & VCCIO 1.8V. VCCPD3A must be 2.5V. It's perfectly valid.