Hard Processor System Technical Reference Manual: Agilex™ 5 SoCs

ID 814346
Date 7/19/2024
Public

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5.8.6.5.7.1. Transfer Command Data Structure

In the master mode of operation, the transfer command is used to initiate CCC and private transfers. For transfers with data payload, additional data structure (either transfer argument or short data argument) is used to provide payload details.

Table 247.  Transfer Command Data Structure
BIT-FIELD FIELD NAME WIDTH DESCRIPTION
31 PEC 1

Parity Error Check Enable

This bit enables generation and validation of PEC byte for SDR CCC and private transfers.

  • 0: PEC check is disabled.
  • 1: PEC check is enabled.
Note: This bit is valid only for SDR Transfers and not for HDR Transfers.
30 TOC 1

Termination On Completion

This bit controls whether a STOP needs to be issued after the completion of the transfer or not.

  • 1 - STOP issued after this transfer.
  • 0 - The next transfer starts with RESTART condition.
29 RESV 1 Reserved
28 RnW 1

Read and Write

This bit controls whether a read or write transfer is performed.

  • 0 - Write transfer
  • 1 - Read transfer
Note: In HDR transfers, this bit is used to set the Read/Write flag of the HDR-TS/HDR-DDR command code.
27 SDAP 1

Short Data Argument Present

This field indicates whether the command written prior to the base command should be treated as short data argument or the transfer argument.

  • 0 - Prior written command is transfer argument.
  • 1 - Prior written command is short data argument.
26 ROC 1

Response On Completion

This field indicates whether the response status is required or not, after the execution of this command for the successful transfer.

  • 1 - Response status is required.
  • 0 - Response status is not required.
Note:
  1. The exception to the control is that the response status gets generated when the transfer has encountered an error condition.
  2. It is recommended that the ROC bit is always set to 1 for the read commands (RnW=1), so that the number of data received is indicated (through the DATA_LENGTH field in response port) if the slave terminates earlier than the master.
25 DBP 1

Defining Byte Present

DBP indicates whether the current CCC command is with defining byte or not. This bit field is valid only when command present (CP) bit is enabled, otherwise this bit is ignored.

  • 0: Defining byte is not present.
  • 1: Defining byte is present.

This bit is applicable only for broadcast and directed SDR CCC transfers.

24 RESV 1 Reserved
23:21 SPEED 3

Speed

This field is used to indicate the speed in which the transfer should be driven.

Values (I3C Mode):

  • 0: SDR0
  • 1: SDR1
  • 2: SDR2
  • 3: SDR3
  • 4: SDR4
  • 5: Reserved
  • 6: Reserved
  • 7: I2C FM

Values (I2C mode):

  • 0: I2C FM
  • 1: I2C FM+
  • 2 -7: Reserved
20:16 DEV_INDX 5

Device Index

This field is used to refer the device address table for getting the target address.

DEV_INDX field points to the offset address of device address table.

15 CP 1

Command Present

This bit is used to control whether the transfer should be initiated with the transfer command represented in the CMD field or not.

0 - CMD field is not valid

1 - CMD field is valid

This bit is applicable for CCC and HDR transfers.

14:7 CMD 8

Transfer Command

This field is used to define the transfer command type. The field can be programmed to:
  • 8-bit common command code for CCC transfers.
6:3 TID 4

Transaction ID

This field is used as the identification tag for the commands. The I3C controller returns this ID along with the response upon completion or upon error.

  • 4'b0000 - 4'b0111 - user-defined TID
  • 4'b1000 - 4'b1111 - reserved for I3C controller.
2:0 CMD_ATTR 3

Command Attribute

Defines the command type and its bit-field format.

  • 0: Transfer command
  • 1: Transfer argument
  • 2: Short data argument
  • 3: Address assignment command
  • 4-7: Reserved