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4.2. CONFIGURATION AND THE DATA PARTITION
As described in a previous section, when using flash to boot the XVF3510 processor, the Data partition
can be used to store commands which are executed immediately after boot-up to configure and define
the functionality of the device. The following sections describe the definition of the Data Partition, how
to generate, and the customisation for specific applications.
4.2.1. DATA PARTITION DEFINITION
PARTITION FILE STRUCTURE
The contents of a Data Partition are defined in a .json file which is passed to a generation script which
forms the binary files used when flashing the device. The generation process is described below, after
the definition .json file is described.
For the purpose of explanation consider the following example for a custom XVF3510-UA Data
Partition:
{
"comment": "",
"spispec_path": "16mbit_12.5mhz_sector_4kb.spispec",
"regular_sector_size": "4096",
"hardware_build": "0xFFFFFFFF",
"item_files": [
{
"path": "input/usb_to_device_rate_48k.txt", "comment": "" },
{
"path": "input/device_to_usb_rate_48k.txt", "comment": "" },
{
"path": "input/usb_mclk_divider.txt", "comment": "" },
{
"path": "input/xmos_usb_params.txt", "comment": "" },
{
"path": "input/i2s_rate_16k.txt", "comment": "" },
{
"path": "input/led_after_boot.txt", "comment":"" }
]
}
Comment pairs are provided for the .json configuration, but also the individual item files:
{ "comment": "" }
A running VocalFusion device needs to know size and geometry of its external QSPI flash in order to
write firmware upgrades to it. This is added to a Data Partition in the form of a flash specification or
SPI specification (See section
{ "spispec_path": "16mbit_12.5mhz_sector_4kb.spispec" }
The Data Partition generation process aligns various sections onto flash sectors, and needs to know
the sector size (this can be found in the flash device datasheet):
{ "regular_sector_size": "4096" }
Hardware build is a custom-defined, 32bit identifier written to flash along with the application firmware.
It can be used to define a unique identifier for the hardware revision or other information which cannot
be overwritten by subsequent updates:
{ "hardware_build": "0xFFFFFFFF" }
Item files which contain the commands to execute (format of item files described below). An optional
comment field is provided:
{ "path": "input/usb_to_device_rate_48k.txt", "comment": "" }
NOTE: Because the generator is a Python script, the paths uses forward slashes irrespective of
platform.
XM-014232-PC
REF
for custom flash support)
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