5.3.2.1 Start Advertising (A[,<hex16>,<hex16>,…])

Format: A[,<hex16>,<hex16>,<hex8>,<hex8>]

Use this command, A, to start an undirected connectable advertisement. The optional parameters follow command A, which means the user can issue the command A with or without parameters. By default, or when command A is issued without any parameter, the advertisement is set as a fast advertisement at first (advertising interval for fast advertising is 20 ms), followed by a low-power slow advertisement after 30 seconds (advertising interval for slow advertising is 961 ms).

Two optional 16-bit hex parameters follow command A, which indicate the advertisement interval with unit of 0.625 ms and total advertisement time with unit of 10 ms, respectively. The range of advertisement interval is from 0x20 (20 ms) to 0xFFFF, and the range of total advertisement time is from 0x00-0xFFFF.

The advertisement stops after completion of the set total advertisement time with a status string %ADV_TIMEOUT%. The optional second parameter must be larger than the first parameter in actual time. When the command A is issued only with the first optional parameter (advertisement interval), the advertisement timeout is no longer effective and the advertisement with interval parameter settings lasts forever.

The A command in the RNBD451 module provide the option to start two different sets of advertisements. By default, the first set of advertisements is a legacy advertisement, and the second set of advertisements is for beacon or extended advertisement.

As per the requirement, the user can select the desired advertisement among both or can start two advertisements at the same time.

The third parameter in the A command indicates the advertising set number. The number of sets can indicate the starting advertisement number, and the value of the parameter is 01 or 02. The value 01 indicates the initiation of one advertisement, and value 02 indicates the initiation of two advertisements.

The fourth parameter in the A command indicates the advertisement index. When the number of advertisements is 2, the advertisement index must be 00. This will start two advertisements. The index number must be 00 or 01 when the set number is 1.

When the advertisement index is 00, it will start the first set of advertisements, and the advertisement index of 01 will start the second set of advertisements. When the total advertising time is not 0, after the total advertising time has elapsed, the advertisement is stopped and it shows a status report, %ADV_TIMEOUT%, to indicate advertising timeout.