For discovering your accessory successfully

You must follow the general advertising guidelines in the Bluetooth Accessory Design Guidelines for Apple Products when constructing your advertising packets. A common mistake is to use improper advertising intervals, either due to misconfiguration or in order to save battery usage on the peripheral. Improper intervals are the most common reasons for your app to not be able to discover your accessory in the field, even though you may have observed discovery working properly in your tests.

The advertising interval of your peripheral affects the time to discovery and connect performance. Outside of ideal conditions, for example when your app is no longer active in the foreground, the time to discovery becomes longer. To maximize the probability of being discovered, the accessory must advertise at one of the listed intervals exactly.

The recommended advertising pattern and advertising intervals are:

• First, advertise at 20 ms intervals for at least 30 seconds

• If not discovered after 30 seconds, you may change to one of the following longer intervals: 152.5 ms, 211.25 ms, 318.75 ms, 417.5 ms, 546.25 ms, 760 ms, 852.5 ms, 1022.5 ms, 1285 ms

For establishing and holding a connection successfully

You must follow the general guidelines in the Bluetooth Accessory Design Guidelines for Apple Products when establishing your connection parameters for your accessory. Common mistakes are to leave these values at their default values, or changing one or more of the parameters without considering the relationship between them.

There are certain rules and formulae that the parameters must follow. If the parameters do not comply with all of these rules, the parameter request may be rejected, or the stability and the performance of the connection may be compromised.

• Interval Min ≥ 15 ms (multiples of 15 ms)

• Interval Min + 15 ms ≤ Interval Max (Interval Max == 15 ms is allowed)

• Interval Max * (Slave Latency + 1) ≤ 2 seconds

• Interval Max * (Slave Latency + 1) * 3 < connSupervisionTimeout

• Slave Latency ≤ 30

• 2 seconds ≤ connSupervisionTimeout ≤ 6 seconds

Use the BLE Parameter Validation Spreadsheet to check that your parameters are correct. Download link is at the end of this page.

BLE Parameter Validation Spreadsheet

• Download BLE Parameter Validation ("qa1931_BLE Parameter Validation.numbers.zip", 79.0K)