NRF52840 high throughput with custom service error changing mtu

RE: NRF52840 high throughput with custom service error changing mtu

superdan1 — Tue, 20 Mar 2018 12:46:42 GMT

After spotted a thread about NRF_SDH_BLE_GATTS_ATTR_TAB_SIZE in DevZone (https://devzone.nordicsemi.com/f/nordic-q-a/30852/data-length-extension-causes-nrf_error_no_mem-on-services-init)
I found a solution for my problem.

Like I suspect it's a memory problem.

I increased the NRF_SDH_BLE_GATTS_ATTR_TAB_SIZE (randomly, no calculation) of 1408 to 8KB (8192) and then the application runs with MTU size of 247 without any errors.

Of course I increased the ram_start value and adjusted the ram_size value of the application too. My values are now:

Physical ram size minus ram_start size = ram_size.

The ram_start size is shown while debbuging in ble_stack_init() method in line err_code = nrf_sdh_ble_enable(&ram_start);
Just read the &ram_start variable.

RAM_START=0x20004800
RAM_SIZE=0x3b800

Apparently there's no fix way to calculate the NRF_SDH_BLE_GATTS_ATTR_TAB_SIZE, so just try out.

Daniel

RE: NRF52840 high throughput with custom service error changing mtu

karthikeyan — Thu, 15 Mar 2018 08:31:08 GMT

hi,

where is the go private button

RE: NRF52840 high throughput with custom service error changing mtu

superdan1 — Tue, 13 Mar 2018 10:48:44 GMT

Hi Ketil,

I don't know how to set this case to private and upload my files?

RE: NRF52840 high throughput with custom service error changing mtu

ketil — Tue, 13 Mar 2018 09:16:22 GMT

Hi,

This is strange behavior. Could you please zip your project files and attach them to this case so we can debug? If your code is sensitive we recommend you click on the GO PRIVATE button before uploading.

Ketil