Forum Discussion
Altera_Forum
Honored Contributor
Honored ContributorIOE and delay chain?
Can i have a silly question here? :confused:
May i know what is IOE (I/O Elements)? why delay chain (D1,D2,D3,D4) is always related to IOE? What is the IOE role in the FPGA? Thanks, fpga897 Replies
Altera_ForumYes, you may.
The IOEs (I/O elements) are the circuitry blocks that actually connect to the FPGA I/O pins. They have the I/O drivers (the circuits which let the FPGA interface with TTL, CMOS, LVDS, SSTL, etc external components) and also tend to have some features to improve I/O timing, like dedicated I/O registers and programmable delay chains.- Altera_Forum--- Quote Start --- They have the I/O drivers (the circuits which let the FPGA interface with TTL, CMOS, LVDS, SSTL, etc external components) and also tend to have some features to improve i/o timing, like dedicated i/o registers and programmable delay chains. --- Quote End --- May i know how the IOE improve the I/O timing? Is it make the delay chain (D1-Dn) either longer or shorter? the delay decide the hong long the data/signal will stay in the I/O pin? what is the purpose of doing this?
- Altera_Forum
Yes, the delay chain can be made longer or shorter as needed.
This may be needed to help with hold violations in I/O timing. - Altera_Forum--- Quote Start --- Yes, the delay chain can be made longer or shorter as needed. This may be needed to help with hold violations in I/O timing. --- Quote End --- May i know if the delay elements will help setup violation as well? Also, how do we determine the delay values? Do we refer to the slack values in timing report to set the delays?
- Altera_Forum
Setup violations are caused by excess delay, so I don't see how the delays can help with setup violations.
The delays are automatically set by the tool as needed, when you have proper I/O constrains. They can also be controlled by user logic, if you have an application where you need to dynamically adjust them. 
zhy1New Contributor
Hello, the device I use is EP4CE10F17C8N. I want to use IOE function to realize programmable delay input and output. How should I call and set it specifically?
- ShengN_altera
Super Contributor
Hi,
This is an older thread. Please open a new thread for new question.
Thanks,
Regards,
Sheng
