Flash storage structure¶
The structure of data within the VocalFusion XVF3610 is arranged to contain a factory image, a single upgrade image, device serial numbers and data partitions for both the factory and upgrade image. This is shown below.
The factory boot image is the executable code for VocalFusion and is supplied in the Release Package in the bin directory. The file format is xe, which refers to XMOS Executable. This is written to the device via the XTAG debugger or through a bulk flash programming operation.
The upgrade boot image, if present, is the executable code written to the flash memory via a DFU operation. Generation of the upgrade boot image is covered below.
The HW build info is specified in the .json Data Partition file for the factory image and is written at the same time as the factory image and Data Partition. It is a unique identifier which is unaffected by subsequent DFU upgrade operations.
The Serial Number is a custom field which can be programmed via USB and I2S control interfaces and remains untouched by the subsequent DFU operations.
The Factory and Upgrade Data Partitions are the associated Data Partitions for the Factory and Upgrade images (where upgrade is present). They are written to flash in the same operation as the boot images. For more information on the generation and usage of Data Partitions see Configuration and the Data Partition section.
NOTE: Storage of only a single upgrade boot image and Data Partition pair are supported. Therefore, any Upgrade image applied will overwrite any existing upgrade image present.
A summary of the factory programming and field update process for flash-based systems is shown in the reference section.