12-04-2018 11:06 PM
iam new to this so kindly please guide me if iam wrong.
Iam using an artix 7 xc7a50t fpga where it has 170 i/o pins, so i wanted to know that whether we can extend the i/o pins using some booster packs or something. Cause i need more i/o pins for my project so please specify if any solution to add more i/o pins by any means.
Thanks in advance
12-04-2018 11:11 PM
12-05-2018 05:19 AM
Depends on what sort of behaviour you want from your pins. For low-speed I/O you can use either I2C I/O expanders or shift registers, which can easily turn two pins into hundreds of pins. However, if you turn 2 pins into 200 pins, the obvious result is that the performance of those pins is going to be 1/100th (or less) than the FPGA pins. For driving LEDs, that's fine. For communicating over USB, it's not going to be quick enough.
If you need "full performance" from the extra pins, then the (only) solution is to buy a chip with more pins, and a board that makes the extra pins accessible.
12-05-2018 11:56 PM
i need extra i/o for reading the status of the relays whether its on or not.
I believe you need GPIO's to just read the status right? If so, what @u4223374 suggested of using I2C IO Expander will work.
However, you mention booster packs in your post. Are you referring to any add on cards to expand your IO pins? If so, you need to provide the details of which board you are using for us to give a better answer for your usecase. Based on your device, I suspect there maybe PMOD headers but can only comment once you confirm on the board details.
12-06-2018 12:04 AM
According to my understand, if the relay status update/change slowly related to the system clock of FPGA(such as 100MHz). You can connect these relay to the shift register chips(parallel to serial), so you can read their status back with few FPGA IO.
If you also want to control relay, you can use the other group of shift register chips(Serial to Parallel).
The fewer IO used, the more time needed to read all relay status. So just make a simple calculation according to your requirement.
12-06-2018 08:18 PM
Thank you for your reply.
Im using an artix-7 xc7a50t-1ft256c. Am actually asking does it support any add on cards for extra GPIO's. And yes i just need to read the status of a relay whether its closed or open so kindly suggest me what i have to do.
12-06-2018 08:56 PM
And here is link for the board i use