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3.2.22. c0, Silicon ID Register

The purpose of the Silicon ID Register is to enable software to identify the silicon manufacturer and revision. The reset value of this register is the SILICONID[31:0] input.

The Silicon ID Register is:

  • a read-only register common for Secure and Nonsecure states

  • accessible in privileged modes only.

Figure 3.17 shows the bit arrangement of the Silicon ID Register.

Figure 3.17. Silicon ID Register format

Figure 3.17. Silicon ID Register format

Table 3.39 shows how the bit values correspond with the Silicon ID Register functions.

Table 3.39. Silicon ID Register bit functions
BitsFieldFunction
[31:24]ImplementorThis field contains a code that identifies the silicon manufacturer. ARM assigns this code.
[23:16]FeatureThis field is implementation-defined.
[15:8]-Reserved, RAZ.
[7:4]Major revisionThis field is implementation-defined.
[3:0]Minor revisionThis field is implementation-defined.

Table 3.40 shows the results of attempted access for each mode.

Table 3.40. Results of access to the Silicon ID Register[20]
Secure privilegedNonsecure privilegedSecure UserNonsecure User
ReadWriteReadWriteReadWriteReadWrite
DataUndefinedDataUndefinedUndefinedUndefinedUndefinedUndefined

[20] An entry of Undefined in the table means that the access gives an Undefined Instruction exception when the coprocessor instruction is executed.


To access the Silicon ID Register, read CP15 with:

MRC p15, 1, <Rd>, c0, c0, 7 ; Read Silicon ID Register