This information applies to the following SoftDevices: S110, S120, S130

Packet Encoding Format

Figure 1: Frame format.

For an architectural overview of Serialized Bluetooth Application, see the Architecture module.

Commands and responses

Figure 2: Command and Response packet course.

Packet Type	Description
0x00 Command	The packet is sent from the application chip to the BLE Connectivity Chip, where it will be decoded and the corresponding function in the SoftDevice is executed.
0x01 Command Response	After a function in the SoftDevice is received, the response is encoded in the BLE Connectivity Chip and a response packet is sent to the application chip.
0x03 DTM Command	The packet is sent from the application chip to the BLE Connectivity Chip, where it will be decoded and the chip will enter in the DTM mode.
0x04 DTM Command Response	Before BLE Connectivity Chip enter in the DTM mode it sends response packet to the application chip.

See BLE S110 Functions, BLE S120 Functions, or BLE S130 Functions for detailed information about functions and responses.

Note: If the length field is invalid for the specific command, the call will return error code NRF_ERROR_INVALID_LENGTH from the codec in the Application Chip.

Events

Figure 3: Event packet course.

Packet Type	Description
0x02 Event	If an event is triggered in the SoftDevice, an event packet is is sent from the BLE Connectivity Chip to the application chip.

See BLE S110 Events, BLE S120 Events, or BLE S130 Events for detailed information about events.