Oad Image Block Characteristic (0Xffc2); Oad Image Count Characteristic (0Xffc3); Figure 7. Reject Notification In Sniffer Capture; Figure 8. Successful Oad Initiation Sniffer Capture - Texas Instruments SimpleLink CC2640 User Manual

Figure 7. Reject Notification in Sniffer Capture

Alternatively, a successful OAD initiation is shown in Figure 8.

Figure 8. Successful OAD Initiation Sniffer Capture

7.4.2 OAD Image Block Characteristic (0xFFC2)

The OAD Image Block characteristic is used to request and transfer a block of the OAD image. "01:00"
shall be written to the CCCD of this characteristic so that notification for block request is enabled. The
target requests the next block of the image by sending a GATT notification to the downloader with the
requested block number. The downloader will respond (GATT write no response) with the block number
and a 16 byte OAD image block. The image block contains the actual binary data from OAD image offset
by the block number. Figure 9 shows a block request/response sniffer capture.

Figure 9. Block Request/Response Sniffer Capture

In Figure 9 above, the block number field is 2 bytes (little endian) and highlighted in red. The OAD image
block is 16 bytes and highlighted in purple.

7.4.3 OAD Image Count Characteristic (0xFFC3)

The OAD Image Count characteristic is used to set the number of OAD images to be downloaded. This is
used for only Off-chip OAD and the default value of the characteristic is 1. Note On-chip OAD only
supports one image download per session. See On-chip OAD 9.1 for details.