The standard mechanism for booting is from an attached QSPI Flash device. This provides standalone operation, and persistent storage for configuration data. VocalFusion XVF3610 supports device firmware upgrade (DFU) over USB (-UA product variant) and I2C (-INT product variant). Pre-compiled host utilities, and source code for reference, are supplied for performing DFU operations.
The following sections discuss the structure of data within the flash memory, and operation of DFU.
While the functionality of the DFU is similar to the USB DFU specification, it has diverged to accommodate both USB and I2C operation and therefore is not compatible with compliant USB DFU tools.