Intel® Agilex™ Configuration User Guide

ID 683673
Date 1/14/2022
Public

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3.2. AS Configuration

In AS configuration schemes, the SDM block in the Intel® Agilex™ device controls the configuration process and interfaces. The serial flash configuration device stores the configuration data. During AS Configuration, the SDM first powers on with the boot ROM. Then, the SDM loads the initial configuration firmware from AS x4 flash. After the configuration firmware loads, this firmware controls the remainder of the configuration process, including I/O configuration and FPGA core configuration. Designs including an HPS, can use the HPS to access serial flash memory after the initial configuration.

Note: The serial flash configuration device must be fully powered up at the same time or before ramping up VCCIO_SDM of the Intel® Agilex™ device. For more information about the power sequence, refer to the Intel® Agilex™ Power Management User Guide.
Important: You must connect the serial flash or quad SPI flash reset pin to the AS_nRST pin. The SDM must fully control the QSPI reset. Do not connect the quad SPI reset pin to any external host.

The AS configuration scheme supports AS x4 (4-bit data width) mode only.

Table 30.   Intel® Agilex™ Configuration Data Width, Clock Rates, and Data Rates
Mode Data Width (bits) Max Clock Rate Max Data Rate MSEL[2:0]
Active Active Serial (AS)

4

166 MHz 664 Mbps

Fast mode - 001

Normal mode - 011

Table 31.  Required Configuration Signals for the AS Configuration Scheme
Configuration Function Pin Type Direction Powered by
nSTATUS SDM I/O Output VCCIO_SDM
nCONFIG SDM I/O Input VCCIO_SDM
MSEL[2:0] SDM I/O Input VCCIO_SDM
AS_nCSO[3:0] SDM I/O Output VCCIO_SDM
AS_DATA[3:0] SDM I/O Bidirectional VCCIO_SDM
AS_CLK SDM I/O Output VCCIO_SDM
AS_nRST 11 SDM I/O Output VCCIO_SDM
Note: Although the CONF_DONE and INIT_DONE configuration signals are not required, Intel recommends that you use these signals. The SDM drives the CONF_DONE signal high after successfully receiving full bitstream. The SDM drives the INIT_DONE signal high to indicate the device is fully in user mode.These signals are important when debugging configuration.

MSEL Pin Function for the AS x4 Configuration Scheme

The SDM samples the MSEL pins immediately after power-on in the SDM Start state. After the SDM samples the MSEL pins, the MSEL pins become active-low chips selects. For AS x4 designs using one flash device, AS_nCSOO asserts low when the SDM starts to communicate with the QSPI flash. The remaining chip select pins, AS_nCSO1 - AS_nCSO3 deassert high.

11 Even if not currently utilized, connect the pin to ensure future compatibility.