1. MAX® 10 I/O Overview
2. MAX® 10 I/O Architecture and Features
3. MAX® 10 I/O Design Considerations
4. MAX® 10 I/O Implementation Guides
5. GPIO Lite Intel® FPGA IP References
6. MAX® 10 General Purpose I/O User Guide Archives
7. Document Revision History for the MAX® 10 General Purpose I/O User Guide
2.3.2.1. Programmable Open Drain
2.3.2.2. Programmable Bus Hold
2.3.2.3. Programmable Pull-Up Resistor
2.3.2.4. Programmable Current Strength
2.3.2.5. Programmable Output Slew Rate Control
2.3.2.6. Programmable IOE Delay
2.3.2.7. PCI Clamp Diode
2.3.2.8. Programmable Pre-Emphasis
2.3.2.9. Programmable Differential Output Voltage
2.3.2.10. Programmable Emulated Differential Output
2.3.2.11. Programmable Dynamic Power Down
3.1. Guidelines: VCCIO Range Considerations
3.2. Guidelines: Voltage-Referenced I/O Standards Restriction
3.3. Guidelines: Enable Clamp Diode for LVTTL/LVCMOS Input Buffers
3.4. Guidelines: Adhere to the LVDS I/O Restrictions Rules
3.5. Guidelines: I/O Restriction Rules
3.6. Guidelines: Placement Restrictions for 1.0 V I/O Pin
3.7. Guidelines: Analog-to-Digital Converter I/O Restriction
3.8. Guidelines: External Memory Interface I/O Restrictions
3.9. Guidelines: Dual-Purpose Configuration Pin
3.10. Guidelines: Clock and Data Input Signal for MAX® 10 E144 Package
3.11. Guidelines: MultiVolt Input for I/O Banks with 3.3 V, 3.0 V, 1.8 V, or 1.5 V VCCIO
3.12. Guidelines: LVTTL/LVCMOS I/O Utilization for MAX® 10 FPGA Package B610
2.4.3.1. OCT Calibration
The OCT calibration circuit compares the total impedance of the output buffer to the external resistors connected to the RUP and RDN pins. The circuit dynamically adjusts the output buffer impedance until it matches the external resisters.
Each calibration block comes with a pair of RUP and RDN pins.
During calibration, the RUP and RDN pins are each connected through an external 25 Ω, 34 Ω, 40 Ω, 48 Ω, or 50 Ω resistor for respective on-chip series termination value of 25 Ω, 34 Ω, 40 Ω, 48 Ω, and 50 Ω:
- RUP—connected to VCCIO.
- RDN—connected to GND.
The OCT calibration circuit compares the external resistors to the internal resistance using comparators. The OCT calibration block uses the comparators' output to dynamically adjust buffer impedance.
During calibration, the resistance of the RUP and RDN pins varies. To estimate of the maximum possible current through the external calibration resistors, assume a minimum resistance of 0 Ω on the RUP and RDN pins.