Thingy 52 receive Microphone Data on nrf52840

[Peter Z]

Hallo guys, 

i tried some hours to receive the microphone and some other data from the Thingy 52 on an nrf52840 evaluation board and write it to an SD-Card. 

Everything works fine, i get the data on the BLE_GATTC_EVT_HVX event, but the package is just 20 bytes long and can't decode as ADPCM on my computer. However, in the iOS-App for the ADPCM package a 131 byte long frame is expected. Why i just receive the 20 bytes?

One of my ideas is, that in the Thingy Source-Code some other Decodes is activated, so I didn't receive the ADPCM data. (Softwareversion 2.1.0) 

Thank you very much for you input. 

Peter Zechel 

[Hung Bui]

Hi Peter, 

 

You would need to support long MTU on your nRF52840 code to receive more than 20 bytes per notification. Make sure the NRF_SDH_BLE_GATT_MAX_MTU_SIZE is configured to match with at least bigger than the size of the characteristic (by default max MTU is 247 bytes) and the connection parameter negotiation (NRF_BLE_GATT_EVT_ATT_MTU_UPDATED event) actually set the MTU to what expected.