Working with SDK 15 on an nRF52832:
I have a peripheral applicatin where I'm computing the value of a BLE read on the fly.
Currently I do that by:
- Setting up a BLE observer
- When it sees a BLE_GATTS_EVT_RW_AUTHORIZE_REQUEST event
- If the operation is read and the attribute is the one in question
- It computes the new value and
- Calls sd_ble_gatts_rw_authorize_reply() to update the value and authorize the read.
But now I want to use data on an external flash to compute the value. Because I'm on a nRF52832 rather than a nRF52840 I don't have the SPIM to memory-map the external flash for read. So I need to kick off some SPI operations to read the data. Those will take a while. So doing them before returning from the event observer is not practical.
Question:
- Does the sd_ble_gatts_rw_authorize_reply() have to be called before the observers have all handled the authorize request BLE event?
- Or can I have:
- my event handler kick off a background process (string of SPI driver calls and callbacks) and return, then
- the background process do the SPI reads, compute the value, and call sd_ble_gatts_rw_authorize_reply() once this is complete?
If the latter doesn't work, how SHOULD I do such an operation?
