Intel® Agilex™ Hard Processor System Technical Reference Manual

ID 683567
Date 2/14/2023
Public

A newer version of this document is available. Customers should click here to go to the newest version.

Document Table of Contents

16.5.9.5.1. The IDENTIFY DEVICE Command

The IDENTIFY DEVICE command returns a 512‑byte data structure to the host that describes device‑specific information and capabilities. The host issues the IDENTIFY DEVICE command only if the MMC block size is set to 512 bytes. Any other MMC block size has indeterminate results.

The host issues a RW_REG command for the ATA command, and the data is retrieved with the RW_BLK command.

The host controller uses the following settings while sending a RW_REG command for the IDENTIFY DEVICE ATA command. The following list shows the primary bit settings:

  • cmd register setting: data_expected bit set to 0
  • cmdarg register settings:
    • Bit [31] set to 0
    • Bits [7:2] set to 128
    • All other bits set to 0
  • Task file settings:
    • Command field of the ATA task file set to 0xEC
    • Reserved fields of the task file set to 0
  • bytcnt register and block_size field of the blksiz register: set to 16

The host controller uses the following settings for data retrieval (RW_BLK command):

  • cmd register settings:
    • ccs_expected set to 1
    • data_expected set to 1
  • cmdarg register settings:
    • Bit [31] set to 0 (read operation)
    • Bits [15:0] set to 1 (data unit count = 1)
    • All other bits set to 0
  • bytcnt register and block_size field of the blksiz register: set to 512