gatt_evt_handler config to set data length to send data by uart

RE: gatt_evt_handler config to set data length to send data by uart

hmolesworth — Thu, 22 Feb 2018 18:25:14 GMT

As Martin says, the key is gatt_init() - see line 488 where 61+3=64 and change from

<p>err_code = nrf_ble_gatt_att_mtu_periph_set(&m_gatt, 64);</p>

to
<p>err_code = nrf_ble_gatt_att_mtu_periph_set(&m_gatt, NRF_SDH_BLE_GATT_MAX_MTU_SIZE);</p>

RE: gatt_evt_handler config to set data length to send data by uart

Martin Lesund — Thu, 22 Feb 2018 12:05:22 GMT

Hi Renato,

You can use the function nrf_ble_gatt_att_mtu_periph_set() (for peripheral side) as described at last post.

You can also take a look at the "ATT_MTU Throughput Example" for reference on how this is handled. Also here is a blog post describing the different parameters.

RE: gatt_evt_handler config to set data length to send data by uart

Renato Silva — Tue, 20 Feb 2018 16:45:49 GMT

Hello Martin,

[quote userid="66115" url="~/f/nordic-q-a/30651/gatt_evt_handler-config-to-set-data-length-to-send-data-by-uart/121431#121431"][/quote]

The question is how many characters you are trying to send?

I want to send a json, and in my solution this structure does not size defined. The size can be between 10 and 255, for example.[quote userid="66115" url="~/f/nordic-q-a/30651/gatt_evt_handler-config-to-set-data-length-to-send-data-by-uart/121431#121431"][/quote]

A proposal is to increase the MTU size on both the peripheral and central side.

Where I can to do it?

[quote userid="66115" url="~/f/nordic-q-a/30651/gatt_evt_handler-config-to-set-data-length-to-send-data-by-uart/121431#121431"]If you look at the "ble_app_uart" example[/quote]

I am working in this example..

RE: gatt_evt_handler config to set data length to send data by uart

Martin Lesund — Tue, 20 Feb 2018 16:21:49 GMT

Hello Renato,

The question is how many characters you are trying to send?

A little more information of what you are trying to achieve would be highly appreciated.

A proposal is to increase the MTU size on both the peripheral and central side.

If you look at the "ble_app_uart" example and take a look in the gatt_init() you can see how this is handled on the peripheral side (nrf_ble_gatt_att_mtu_periph_set()).

(similar Thread about MTU size)