BLE read/write synchronization

RE: BLE read/write synchronization

Simonr — Wed, 23 Aug 2023 11:05:04 GMT

Is the mobile app a custom one you are developing as well? If so are you able to see what the mobile is doing with this data exactly? And do you get a confirmation that the data the nRF52 device writes to the mobile app is indeed forgotten/erased afterwards, so new data isn't overwritten and makes this the "garbage" data? I think you need to confirm that it is in fact erased between writes.

Best regards,

Simon

RE: BLE read/write synchronization

Polek — Mon, 21 Aug 2023 14:07:52 GMT

I do periodically write data (116 bytes) to characteristic on a device side, mobile app receives this data and write back to its characteristic some data (4 bytes). Writing data from device is performed periodically without waiting any seq/packet from mobile, just write and forget, but mobile use the same characteristic for writing themself data independently from device. Maybe in the last sentence error is located...?

RE: BLE read/write synchronization

Simonr — Mon, 21 Aug 2023 10:35:34 GMT

Okay, thank you for the update. From what you've provided, the code looks simple enough and correct from what I can tell, and we don't think the ble_evt_handler is doing something wrong here, but rather that some garbage or corrupted data is being written into the characteristic and then reading this value back. Can you provide some information on what you're writing into the characteristic on your end?

Best regards,

Simon

RE: BLE read/write synchronization

Polek — Fri, 18 Aug 2023 07:18:03 GMT

nRF5_SDK_16.0.0

RE: BLE read/write synchronization

Simonr — Fri, 18 Aug 2023 06:38:25 GMT

What SDK and version are you using for development here? I think setting the ram_start here to 0 might be what's causing issues.

Best regards,

Simon

RE: BLE read/write synchronization

Polek — Thu, 17 Aug 2023 13:14:58 GMT

I receive this garbage from:

static void ble_evt_handler(ble_evt_t const * p_ble_evt, void * p_context);

in p_ble_evt already garbage on write event...

And here is example how I setup ble stack:

static void init_ble()

{

ret_code_t ec = nrf_sdh_enable_request();

APP_ERROR_CHECK(ec);

uint32_t ram_start = 0U;

ec = nrf_sdh_ble_default_cfg_set(APP_BLE_CONN_CFG_TAG, &ram_start);

APP_ERROR_CHECK(ec);

ec = nrf_sdh_ble_enable(&ram_start);

APP_ERROR_CHECK(ec);

NRF_SDH_BLE_OBSERVER(s_ble_observer, APP_BLE_OBSERVER_PRIO, ble_evt_handler, nullptr);

}

RE: BLE read/write synchronization

Simonr — Thu, 17 Aug 2023 11:56:39 GMT

How do you store this data exactly? Could it be that your buffers or flash addresses are being filled or overwritten causing the received characteristics data to seem like garbage. Can you provide some details of the service and characteristics you're trying to use, and what the issue is exactly, as I'm not sure I understand you.

Best regards,

Simon