General-Purpose I/O User Guide: Agilex™ 3 FPGAs and SoCs
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Ixiasoft
Visible to Intel only — GUID: xvl1658233525624
Ixiasoft
2.4.1.2. OCT Calibration Block
The OCT calibration block can calibrate the I/O buffers located in the same HSIO banks only. For example, you can use the OCT calibration block in bank 2A to calibrate the I/O buffers in bank 2A only.
The OCT calibration process uses the RZQ pin that is available in every HSIO sub-bank for series-calibrated and parallel-calibrated terminations.
- You can use the RZQ pin in one sub-bank to calibrate I/Os in the other sub-bank within the same HSIO bank. For example, you can use the RZQ pin in the bottom index sub-bank of bank 2B to calibrate the I/Os in the top index sub-bank of bank 2B. Both sub-bank must use the same VCCIO_PIO voltage value.
- The RZQ pin is a dual-purpose I/O pin and functions as a general-purpose I/O pin if you do not use the calibration circuit.
- The RZQ pin shares the same VCCIO_PIO supply voltage with the I/O sub-bank where the pin is located.
The OCT calibration block has an external 240 Ω reference resistor associated with it through the RZQ pin available in every sub-bank.
- Connect the RZQ pin to GND through an external 240 Ω resistor.
- For differential I/O standards, you must use the same RZQ resistor to calibrate both the positive and negative legs of the differential I/O pin.
- You can use each RZQ resistor to calibrate two RS OCT settings and one RT OCT setting for all I/O standards.