6.2.1 Firmware Download Detection

The host determines if the ATWILC Microprocessor Control Unit (MCU) is running firmware that is downloaded or running from the Boot ROM. The host determines if a new version of firmware is to be used. The detection is finished by reading the local version through the standard Read Local Version HCI command Op Code 0x1001 and checking for byte number '7' in the HCI event packet sent back from the Bluetooth controller as follows:

• If byte 7 is 255, then the Boot ROM code is running on the CPU
• If byte 7 is 6, then the firmware code is running on the CPU