Command READCFM

This command reads an address in the NVMCTRL::CFM space and returns the data. If the address is read-protected or out of range, the device returns an invalid argument status and waits for another command. If the address is within range, the command succeeds with data valid status, followed by the data.

This procedure allows one 32-bit value to be read at a time, but continues accepting target addresses until an address outside the allowable range is requested. By convention, write a target address of 32’h0000_0000 when you intentionally want to exit this procedure.

The Table 6-11 defines the command structure, and Figure 6-6 shows the communication sequence.

Table 6-11. CMD_READCFM Definition
Type	Input	Size	Range	Output	Comment
Command	`CMD_READCFM`			STATUS_ERR_EXEC STATUS_ARG_INVALID STATUS_CMD_VALID	Refer to Table 6-9 and Table 6-10
Argument1	Address	32 bits	Refer to Table 6-12	STATUS_ARG_INVALID	The command is aborted on an address error. This is how the command is intentionally ended. Refer to Table 6-9
Result				STATUS_ERR_ECC STATUS_DATA_VALID	Refer to Table 6-9 and Table 6-10
Returns		32 bits		Data	The command awaits a new Address after a valid read

Table 6-12. READ_CFM Valid Addresses
Region	Description
`CFM::SIGNATURE`	Firmware metadata
`CFM::BOOTCFG`	User configuration

Figure 6-6. CMD_READCFM Message Sequence