Cirrus Logic CS4970x4 - Manual (Page 131)

8-21 Copyright 2013 Cirrus Logic, Inc. DS810UM6
Creating a Flash Image
CS4953x4/CS4970x4 System Designer’s Guide
Figure 8-15. Blank SPI Flash Format
8.7.1.1 Master Boot Image (egg.img)
The Master Boot Image, which is created by the DSP condenser tool, is customer system-specific. The
Master Boot image is located in a locked area of SPI Flash, and must start at start at location 0x0000. The
area designated for the Master Boot image is not updated during Field Flash updates. See
Section
8.7.1.2. for more information. The Master Boot image contains code to:
• Lock the PLL to a nominal 150 MHz
• Read/write the attached Flash
• Validate the updatable Flash image. If image is not valid, automatically goes into Flash update mode
• Run Flash update from audio source
• If Flash image is valid, boot either the power-down saved state or a factory-set default state
The Master Boot image has a pointer in it to the flash_address where the remainder of the updatable
Flash image is stored. This value is patched into the Master Boot image via uld_merge by the DSP
Condenser tool during the design stage, when the Flash images are being created. It also has a pointer to
the DSP State Space (described in
Section 8.7.1.3. ) in Flash. This pointer is also patched into the Master
Boot image when the Flash images are being created.
8.7.1.2 Updatable Flash Image
The Field Upgrade SPI Flash image is created using the flash_to_wav utility, and contains multiple data
structures, ULDs, and configuration message sets. The Flash update image is formatted as a .WAV file,
so the first part of the file is the .WAV header. The data payload of the .WAV file is organized as an IEC-
61937 (SPDIF) digital stream.
8.7.1.3 DSP State Space
An area of Flash reserved for DSP usage. It is used to store:
• The power-off state
• Configuration values calculated by room calibration modules