WM8321
Production Data
It is recommended to re-lock the protected registers immediately after writing to them. This helps
protect the system against accidental overwriting of register values. To lock the protected registers, a
value of 0000h should be written to the Security register.
ADDRESS
R16392 (4008h)
Security Key
BIT
LABEL
DEFAULT
DESCRIPTION
Security Key
SECURITY
[15:0]
15:0
0000h
A value of 9716h must be written
to this register to access the user-
keyed registers.
Table 13 Security Key Registers
12.5 SOFTWARE RESET AND CHIP ID
A Software Reset can be commanded by writing to Register 0000h. This is a read-only register field
and the contents of this register will not be affected by a write operation. For more details of the
different reset types, see Section 24.
Note that a maximum of 6 Software Resets is permitted. If more than 6 Software Resets are
scheduled, the WM8321 will remain in the OFF state until the next valid ON state transition event
occurs.
The Chip ID can be read back from Register 0000h. Other ID fields can be read from the registers
defined in Table 14.
ADDRESS
R0 (0000h)
BIT
LABEL
CHIP_ID
[15:0]
DEFAULT
DESCRIPTION
Writing to this register causes a
Software Reset. The register map
contents may be reset, depending
on SW_RESET_CFG.
15:0
0000h
Reset/ID
Reading from this register will
indicate Chip ID.
R1 (0001h)
Revision
PARENT_RE
V [7:0]
The revision number of the parent
die
15:8
7:0
00h
00h
CHILD_REV
[7:0]
The revision number of the child
die (when present)
R16384 (4000h)
Parent ID
PARENT_ID
[15:0]
The ID of the parent die
15:0
6246h
Table 14 Reading Device Information
12.6 SOFTWARE SCRATCH REGISTER
The WM8321 provides one 16-bit register as a “Software Scratch” register. This is available for use
by the host processor to store data for any purpose required by the application.
The contents of the Software Scratch register are retained in the BACKUP power state.
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R16393 (4009h)
Software Scratch
SW_SCRATC
H [15:0]
Software Scratch Register for use
by the host processor.
15:0
0000h
Note that this register’s contents
are retained in the BACKUP power
state.
Table 15 Software Scratch Register
PD, February 2012, Rev 4.0
44
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
