WM8326 Datasheet, PDF (52/255 Pages) Wolfson Microelectronics plc – Processor Power Management Subsystem

WM8326
Production Data
Figure 19 ICE Memory Connection
Note that the WM8326 does not support programming the external ICE memory.
External programming of ICE whilst physically connected to the WM8326 is possible by putting the
WM8326 in the OFF state. This is supported on the evaluation board, provided the voltage levels on
SCLK2 and SDA2 are less than or equal to the LDO12 VPMIC voltage. Note that the Write-Protect
(WP) pin on the ICE must be connected to GND (Vss) in this case.
14.4 OTP / ICE MEMORY CONTROL
The OTP and ICE Memory commands are initiated by writing to the OTP Control Register, as defined
in Section 14.4.6. The supported commands are described below.
READ ICE MEMORY - This command instructs the WM8326 to load data from the external ICE into
the WM8326 DCRW memory area. Note that this command is performed automatically when the
WM8326 starts up in development mode.
READ OTP MEMORY - This command instructs the WM8326 to load data from the integrated OTP
memory area into the WM8326 DCRW memory area. Note that this command is performed
automatically when the WM8326 starts up in normal (ie. non-development) mode.
WRITE OTP MEMORY - This command instructs the WM8326 to program the integrated OTP, by
writing a copy of the DCRW memory area (Pages 0, 1, 2 and 3) to the OTP memory. This command
should be performed after the required settings have been configured in the DCRW memory. The
required settings can be configured in the DCRW either as a result of a ICE Read command, or else
through register writes in the PROGRAM power state. Note that the Write OTP command should only
be performed once on each OTP page; after the Write OTP command has been performed, the
contents of the affected page(s) cannot be erased or re-programmed.
VERIFY OTP MEMORY - This command instructs the WM8326 to compare the contents of the OTP
memory with the contents of the DCRW memory. The Verify OTP command performs a check that
the OTP data is identical to the DCRW contents, in order to confirm the success of the Write OTP
operation. For increased reliability, the WM8326 can apply a ‘Margin Read’ function when verifying
the OTP memory; it is recommended that the Margin Read option is used, as described in
Section 14.4.4.
FINALISE OTP PAGES - This command instructs the WM8326 to set the OTP_CUST_FINAL bit in
the OTP memory. The Finalise OTP command ensures that any subsequent OTP_WRITE commands
to Page 2 or Page 3 of the OTP will have no effect and that the OTP contents are maintained
securely.
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PD, June 2012, Rev 4.0
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