sd_ble_gatts_exchange_mtu_reply()

uint32_t sd_ble_gatts_exchange_mtu_reply	(	uint16_t	conn_handle,
		uint16_t	server_rx_mtu )

#include <ble_gatts.h>

Reply to an ATT_MTU exchange request by sending an Exchange MTU Response to the client.

This function is only used to reply to a BLE_GATTS_EVT_EXCHANGE_MTU_REQUEST event.

The SoftDevice sets ATT_MTU to the minimum of:

• The Client RX MTU value from BLE_GATTS_EVT_EXCHANGE_MTU_REQUEST, and
• The Server RX MTU value.

However, the SoftDevice never sets ATT_MTU lower than BLE_GATT_ATT_MTU_DEFAULT.

Relevant Message Sequence Charts

GATTS ATT_MTU Exchange

Parameters

[in]	conn_handle	The connection handle identifying the connection to perform this procedure on.
[in]	server_rx_mtu	Server RX MTU size. The minimum value is BLE_GATT_ATT_MTU_DEFAULT. The maximum value is ble_gatt_conn_cfg_t::att_mtu in the connection configuration used for this connection. The value must be equal to Client RX MTU size given in sd_ble_gattc_exchange_mtu_request if an ATT_MTU exchange has already been performed in the other direction.

Return values

NRF_SUCCESS	Successfully sent response to the client.
BLE_ERROR_INVALID_CONN_HANDLE	Invalid Connection Handle.
NRF_ERROR_INVALID_STATE	Invalid Connection State or no ATT_MTU exchange request pending.
NRF_ERROR_INVALID_PARAM	Invalid Server RX MTU size supplied.
NRF_ERROR_TIMEOUT	There has been a GATT procedure timeout. No new GATT procedure can be performed without reestablishing the connection.