SWRA478D February 2015 – January 2019 CC1310 , CC1312PSIP , CC1312R , CC1314R10 , CC1352P , CC1352P7 , CC1352R , CC2640 , CC2640R2F , CC2640R2F-Q1 , CC2642R , CC2642R-Q1 , CC2650 , CC2650MODA , CC2652P , CC2652R , CC2652R7 , CC2652RB , CC2652RSIP
6.3.1 Advertising Event
An advertising event is where the (Bluetooth Low Energy) peripheral device broadcasts information in order to either share information or become connected to a (Bluetooth Low Energy Ready) Central device, such as a smart phone. The device wakes up and broadcasts packets on three separate channels and listens on each of these channels for Scan Requests or Connection Requests. Scan Requests is a way for a Central device to obtain more information about the device before connecting, because the advertising data is typically chosen to be very short to minimize power consumption. Based on advertising data or the scan response data, connection requests can be sent, which initiates a connection between the Peripheral and the Central.
With connectable advertising packet format, the base time of data transmitting is 144 µs, which contains a pilot tone plus 1 byte preamble, 4 bytes Access Address, 2 bytes PDU, 3 bytes CRC and 6 bytes AdvA in the payload. For every additional transmitted bit, 1 µs should be added to the TX time.
The Agilent 14585A Control and Analysis Software “Markers & Measurements” functions are used to quantify a single advertising event, which is visualized in Figure 6-13 and summarized in Table 6-1.
Figure 6-13 Connectable Advertising Event, Capture| Number | State | Comments |
|---|---|---|
| 1 | Pre-processing | RTOS wake-up, radio setup, XTAL guard time |
| 2 | Radio preparation | Radio is turned on and in transition to TX |
| 3 | TX | The radio transmits an advertisement packets with 3 bytes data on Channel 37. Time is dependent on amount of transmitted data |
| 4 | TX to RX transition | TX to RX transition |
| 5 | RX | Time depends on advertising interval and Sleep Crystal Accuracy (SCA) |
| 6 | RX to TX transition | RX to TX transition |
| 7 | TX | The radio transmits an advertisement packets with 3 bytes data on Channel 38. Time is dependent on amount of transmitted data |
| 8 | TX to RX transition | TX to RX transition |
| 9 | RX | Time depends on advertising interval and SCA |
| 10 | RX to TX transition | RX to TX transition |
| 11 | TX | The radio transmits an advertisement packets with 3 bytes data on Channel 39. Time is dependent on amount of transmitted data |
| 12 | TX to RX transition | TX to RX transition |
| 13 | RX | Time depends on advertising interval and SCA |
| 14 | Post-processing and going to Standby | Bluetooth Low Energy protocol stack processes the received packets and sets up the sleep timer in preparation for the next event, and then goes to Standby |
This is also the event occurring when a device is in beacon mode. For a non-connectable beacon, there are no RX states during the advertising event, reducing the average current consumption.
Figure 6-14 Beacon Event, Capture| Number | State | Comments |
|---|---|---|
| 1 | Pre-processing | RTOS wake-up, radio setup, XTAL guard time |
| 2 | Radio preparation | Radio is turned on and in transition to TX |
| 3 | TX | The radio transmits an advertisement packets with 3 bytes data on Channel 37. Time is dependent on amount of transmitted data |
| 4 | TX-to-TX transition | TX to TX transition |
| 5 | TX | The radio transmits an advertisement packets with 3 bytes data on Channel 38. Time is dependent on amount of transmitted data |
| 6 | TX-to-TX transition | TX to TX transition |
| 7 | TX | The radio transmits an advertisement packets with 3 bytes data on Channel 39. Time is dependent on amount of transmitted data |
| 8 | Post-processing and going to Standby | Bluetooth Low Energy protocol stack sets up the sleep timer in preparation for the next event, and then goes to Standby |