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ARMmbed / ble-nrf51822

Nordic stack and drivers for the mbed BLE_API
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Terrible handling of initLen / minLen and variable length characteristics. #56

Closed Timmmm closed 8 years ago

Timmmm commented 8 years ago

(This is a duplicate of https://github.com/ARMmbed/ble/issues/93 as it affects both projects.)

See: https://devzone.nordicsemi.com/question/34390/no-ble_gatt_hvx_notification-under-20-bytes/?answer=55637#post-id-55637

Basically there are two problems:

  1. The GattCharacteristic initLen parameter is randomly named minLen too. If you follow the code all the way through it actually does two things - it is the initial length (not minimum), and it determines whether the characteristic is variable length or not.
  2. The characteristic for nRF51822 code is only variable length if initLen != maxLen. This is really stupid because you might want the initial length to equal the maximum length but still have variable length. It also isn't documented anywhere.

I suggest the following solution:

  1. Add extra constructors with an extra parameter: bool variableLength.
  2. Name initLen to be initLen everywhere consistently (and not minLen).
  3. Deprecate the old constructors.
rainierwolfcastle commented 8 years ago

ARM Internal Ref: IOTSFW-1156

andresag01 commented 8 years ago

I believe this has been solved in https://github.com/ARMmbed/ble-nrf51822/commit/3fb32e167fa9c39f31d3786acd0c59485c621e87