Intel Agilex® 7 General-Purpose I/O User Guide: M-Series

ID 772138
Date 12/04/2023
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2.4.1.1.1. RS OCT

M-Series devices support RS OCT with and without calibration.
Table 11.  RS OCT Schemes
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 stops changing the characteristics of the drivers.
  • In EMIF mode, you may trigger recalibration during user-mode.
Figure 7. RS OCT without Calibration This figure shows the RS as the total impedance of the output buffer.
Figure 8. RS OCT with Calibration This figure shows the RS as the total impedance of the output buffer.
Table 12.  Selectable I/O Standards for RS OCT for GPIO-B BanksThe default values are in bold font.
I/O Standard RS OCT without Calibration5 (Ω) RS OCT with Calibration (Ω)
1.3 V LVCMOS 34, 40
1.2 V LVCMOS 34, 40
1.1 V LVCMOS 34, 40
1.05 V LVCMOS 34, 40
SSTL-12 34, 40 34, 40
HSTL-12 34, 40 34, 40
HSUL-12 34, 40 34, 40
POD12 34, 40 34, 40
POD11 34, 40 34, 40
LVSTL11 34, 40 34, 40
LVSTL105 34, 40 34, 40
LVSTL700 40
Differential SSTL-12 34, 40 34, 40
Differential HSTL-12 34, 40 34, 40
Differential HSUL-12 34, 40 34, 40
Differential POD12 34, 40 34, 40
Differential POD11 34, 40 34, 40
Differential LVSTL11 34, 40 34, 40
Differential LVSTL105 34, 40 34, 40
Differential LVSTL700 40
SLVS-400 45
5 Supported only in GPIO mode.