Intel® Agilex™ F-Series and I-Series General-Purpose I/O User Guide

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ID 683780
Date 6/14/2022
Public
Document Table of Contents

2.4.1.1.1. RS OCT

Intel® Agilex™ devices support RS OCT with and without calibration for single-ended and voltage-referenced I/O standards.
OCT Scheme Description
RS without calibration
  • Available on output buffer only.
  • Driver-impedance matching provides the I/O driver with a controlled output impedance that closely matches the impedance of the transmission line.
RS with calibration
  • The RS OCT calibration circuit uses the impedance of the external resistor connected to the RZQ pin as a reference.
  • During calibration, the circuit continuously alters the impedance of the I/O buffer until the value reaches the target impedance, which is a predetermined ratio to the reference resistance.
  • The calibration occurs at the end of the device configuration. When the calibration circuit finds the correct impedance, the circuit powers down and stops changing the characteristics of the drivers.
  • You may trigger recalibration during user-mode.
Figure 7. RS OCT without CalibrationThis figure shows the RS as the intrinsic impedance of the output transistors.
Figure 8. RS OCT with CalibrationThis figure shows the RS as the intrinsic impedance of the output transistors.
Table 10.  Selectable I/O Standards for RS OCT for GPIO BanksThe default values are in bold font.
I/O Standard RS OCT without Calibration (Ω) RS OCT with Calibration (Ω)
1.2 V LVCMOS 34, 40 34, 40
SSTL-12 34, 40 34, 40
POD12 34, 40 34, 40
HSTL-12 34, 40 34, 40
HSUL-12 34, 40 34, 40
Differential SSTL-12 34, 40 34, 40
Differential POD12 34, 40 34, 40
Differential HSTL-12 34, 40 34, 40
Differential HSUL-12 34, 40 34, 40

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