ANCS with MTU > 23

[gotthcha]

I tried to set up the ANCS example. It works fine. But how is it possible to set a higher MTU. I set the NRF_BLE_GATT_MAX_MTU_SIZE to 247. But the Log says after a connect:

nrf_ble_gatt:DEBUG:Requesting to update ATT MTU to 247 bytes on connection 0x0.
 0> nrf_ble_gatt:ERROR:sd_ble_gattc_exchange_mtu_request() returned unexpected value 0x7.
 0> nrf_ble_gatt:DEBUG:Requesting to update data length to 251 on connection 0x0.
 0> nrf_ble_gatt:ERROR:sd_ble_gap_data_length_update() (request) on connection 0x0 returned unexpected value 0x13.
 0> nrf_ble_gatt:DEBUG:Peer on connection 0x0 requested a data length of 251 bytes.
 0> nrf_ble_gatt:DEBUG:Updating data length to 251 bytes on connection 0x0.
 0> nrf_ble_gatt:ERROR:sd_ble_gap_data_length_update() (reply) returned unexpected value 0x13.

How can i set up a higher MTU? nrf52832 with SD 4.0.1 sdk 13

[Coldson]

@gotthcha

I have try to modify MTU size before, but on CSR and BRCM platform.

And I have a question for u, which version u r current using? iOS 10?

As I remember, when in iOS 7 MTU size on the iPhone can only up to 128 byte

iOS 8 MTU size 135, iOS 9 MTU size 158, iOS 10 MTU size is 185 byte,

This image below is the nRF52832 connect with iOS 9,

Can U just using 185 byte or less, and give it a try?

BTW: "Invalid Parameter" is the error code 0x07 u got.

#define 	NRF_ERROR_INVALID_PARAM   (NRF_ERROR_BASE_NUM + 7)