Intel® Arria® 10 Core Fabric and General Purpose I/Os Handbook

ID 683461
Date 10/25/2023
Document Table of Contents

7.3.2. CLKUSR

You can use CLKUSR pin as the clock source for Arria® 10 device configuration and initialization. CLKUSR pin can also be used for configuration and transceiver calibration simultaneously.

For transceiver calibration, CLKUSR must be a free-running clock running between 100 MHz to 125 MHz at power-up depending on the device’s configuration scheme as shown in the following table. Transceiver calibration starts utilizing the CLKUSR during device configuration and may continue to use it even when the device enters user mode.
Note: CLKUSR cannot be used as the reference clock for PLL.
Table 97.  Available Configuration Clock Source and Transceiver Calibration CLKUSR Frequency for Arria® 10 Devices
Configuration Scheme Supported Clock Source for Device Configuration Supported Clock Source for Device Initialization Supported CLKUSR Frequency for Transceiver Calibration
AS Internal Oscillator Internal Oscillator 100 to 125 MHz
PS DCLK only Internal Oscillator, CLKUSR, DCLK 100 to 125 MHz
FPP (x8, x16, x32)