3.1. Guideline: VREF Sources and VREF Pins
3.2. Guideline: Observe Device Absolute Maximum Rating for 3.0 V Interfacing
3.3. Guideline: Voltage-Referenced and Non-Voltage Referenced I/O Standards
3.4. Guideline: Do Not Drive I/O Pins During Power Sequencing
3.5. Guideline: Stratix® 10 I/O Buffer During Power Up, Configuration, and Power Down
3.6. Guideline: Maximum DC Current Restrictions
3.7. Guideline: Use Only One Voltage for All 3 V I/O Banks
3.8. Guideline: I/O Standards Limitation for Stratix® 10 TX 400
3.9. Guideline: I/O Standards Limitation for Stratix® 10 GX 400 and SX 400
2.2.2. I/O Buffer and Registers in Stratix® 10 Devices
I/O registers are composed of the input path for handling data from the pin to the core, the output path for handling data from the core to the pin, and the output enable (OE) path for handling the OE signal to the output buffer. These registers allow faster source-synchronous register-to-register transfers and resynchronization. Use the GPIO Intel® FPGA IP to utilize these registers to implement DDR circuitry.
The input and output paths contain the following blocks:
- Input registers—support half or full rate data transfer from peripheral to core, and support double or single data rate data capture from I/O buffer.
- Output registers—support half or full rate data transfer from core to peripheral, and support double or single data rate data transfer to I/O buffer.
- OE registers—support half or full rate data transfer from core to peripheral, and support single data rate data transfer to I/O buffer.
The input and output paths also support the following features:
- Clock enable.
- Asynchronous or synchronous reset.
- Bypass mode for input and output paths.
- Delays chains on input and output paths.
Figure 6. IOE Structure for Stratix® 10 DevicesThis figure shows the Stratix® 10 FPGA IOE structure.
Note: The GPIOs in the 3 V I/O banks do not have I/O registers.