In my application, I need to the mix the outputs of the two ADF4350's. There's a need to control the two devices, which can be done by doing it in SPI interface. The usb controller that was used in the evaluation boards was the EZ-USB FX2LP, which also gives the SPI signals. I also asked a copy of the firmware which is the "adf4xxx_usb_fw_1_0" and tried to load it (into the controller's development kit), and the evaluation board software can communicate with it. I want to introduce an extra pin output for the LE signal, thus I need to modify the firmware. But, whenever I load the modified firmware to the controller, the controller behaves as if it has the original firmware.
I speculate that whenever the ADF4xxx device driver detects the controller, the driver loads a copy of the firmware to the controller overwriting the firmware which was previously downloaded.
Is my speculation correct?
How can I make the controller load my modified firmware?