BLE connection lost after Flash write

RE: BLE connection lost after Flash write

Kenneth — Wed, 06 Nov 2019 12:19:51 GMT

The softdevice can buffer about 6-8packets (more or less depending on configuration), if you need larger buffer you need to handle this in the application. For instance use use an app_timer (e.g. every 10ms) that will try to offload the data by calling sd_ble_gatts_hvx() until NRF_ERROR_RESOURCES occurs.

RE: BLE connection lost after Flash write

raghuhn — Tue, 05 Nov 2019 12:43:16 GMT

i am using ses

RE: BLE connection lost after Flash write

Wei — Thu, 19 Sep 2019 17:32:58 GMT

Hi Kenneth:

Now, I try to save the ADC sampling data (250Sa/s) to the BLE chip flash memory first, and then after triggered, data is read from flash and transferred out through bluetooth. The trigger now is "after finishing the flash write".

For flash write and Read, it's in a packet size of 64 samples. The problem is if I write 4 packets, and read/transfer 4 packets ( total data volume is 64*4 =256 samples), the software works fine. If I write and read/transfer more than 4 packets. the BLE software can be restarted/reset frequently. Double check the data pattern using a terminal software find, the restart/reset happens after/in the last packet write. this is because of the APP_ERROR_CHECK(err_code).

This is my application request. How can I check the BLE_GATTS_EVT_HVN_TX_COMPLETE event? So I can transfer as many packets as possible in one time transfer? So I can read the saved data from flash memory and transfer them out in one time, like may be with the data size of 64packets * 128 bytes, or bigger.

Thanks

Wei

RE: BLE connection lost after Flash write

Wei — Thu, 19 Sep 2019 17:11:07 GMT

By the way, can I change the tx buffer length ?

Thx

RE: BLE connection lost after Flash write

Kenneth — Thu, 19 Sep 2019 17:11:05 GMT

I think it is easier to help you if you can describe what you want to do.

Most just send notification by calling sd_ble_gatts_hvx() until NRF_ERROR_RESOURCES, wait for BLE_GATTS_EVT_HVN_TX_COMPLETE event, and then call sd_ble_gatts_hvx() until NRF_ERROR_RESOURCES again. This can be repeated indefinitely.

Just be aware that you will get one BLE_GATTS_EVT_HVN_TX_COMPLETE for many sd_ble_gatts_hvx() calls.

If you want to know how many notifications that was actually sent you need to check p_ble_evt->evt.gatts_evt.params.hvn_tx_complete.count on BLE_GATTS_EVT_HVN_TX_COMPLETE event.

RE: BLE connection lost after Flash write

Wei — Thu, 19 Sep 2019 16:46:36 GMT

No, I did not do that.

What's that, and should I do that? See some example codes, do not see they do this. Or do you more information about this?

Wei

RE: BLE connection lost after Flash write

Kenneth — Thu, 19 Sep 2019 16:42:03 GMT

It's only when you receive err_code = NRF_SUCCESS that the packet is queued to be sent as notification. Do you take into account that when you receive the BLE_GATTS_EVT_HVN_TX_COMPLETE event you also need to check the counter value to know how many packets were sent?

p_ble_evt->evt.gatts_evt.params.hvn_tx_complete.count

RE: BLE connection lost after Flash write

Wei — Thu, 19 Sep 2019 15:39:35 GMT

Hi Kenneth:

thanks for continuously support on this topic.

In my application, I need transfer out bulk data in one time. Like in the tested application, it need transfer out 6 packets of 128 bytes in one time.

I tried your code, it can connect with the master without break, but it only transfer 1 packet, while lost the other 5 packets.

I happen to try this code:

									if(tx_in_progress == false)
									{	}
										tx_in_progress = true;										
										err_code = ble_nus_string_send(&m_nus, value, bytes_to_send);										
										if ((err_code != NRF_ERROR_INVALID_STATE) && (err_code != NRF_ERROR_BUSY) && (err_code != NRF_ERROR_RESOURCES))
										{
											APP_ERROR_CHECK(err_code);
										} 
										if (err_code != NRF_SUCCESS)
										{
												tx_in_progress = false;
										}

This code can transfer 4 packets, while lost the other 2 packets.

In my previous code, 4 packets is the maximum number I can get for the one time transfer.

thanks

Wei

RE: BLE connection lost after Flash write

Kenneth — Thu, 19 Sep 2019 08:08:00 GMT

I was thinking more like this, in main.c:

if(tx_in_progress == false)
{
	tx_in_progress = true;
    err_code = ble_nus_string_send(&m_nus, value, bytes_to_send);
    
    if ((err_code != NRF_ERROR_INVALID_STATE) && (err_code != NRF_ERROR_BUSY) && (err_code != NRF_ERROR_RESOURCES))
    {
    	APP_ERROR_CHECK(err_code);
    }
    if (err_code != NRF_SUCCESS)
    {
        tx_in_progress = false;
    }
}

RE: BLE connection lost after Flash write

Wei — Wed, 18 Sep 2019 19:30:21 GMT

Hi Kenneth:

thanks for the reply.

First, I tried your code. But it still not work.

My problem is I need read from flash memory, and send the large bulk data out though BLE. The packet size 64 samples, 128 bytes. As I continuously read from flash, and send out. I add the BLE_GATTS_EVT_HVN_TX_COMPLETE to check the transfer complete, like using your code. But in my application, the BLE_GATTS_EVT_HVN_TX_COMPLETE event is not triggered. and the tx_in_progress is always TRUE.

What's the possible reason for this? How can I debug it?

Add new code here.

Thanks

					case BLE_GATTS_EVT_HVN_TX_COMPLETE:
					tx_complete = true;
					tx_in_progress = false;
					break;
					
					
in main.c
									printf("%x\r\n", tx_in_progress);
								if(tx_in_progress == false)
								{
									tx_in_progress = true;
									
									err_code = ble_nus_string_send(&m_nus, value, bytes_to_send);
									if ((err_code != NRF_ERROR_INVALID_STATE) && (err_code != NRF_ERROR_BUSY))
									{
										APP_ERROR_CHECK(err_code);
										tx_in_progress = false;
									}	
								}

RE: BLE connection lost after Flash write

Kenneth — Wed, 18 Sep 2019 18:18:07 GMT

I don't understand the flow here and I don't like infinite while loops, so maybe try something like this instead:

static volatile bool tx_in_progress;

in on_ble_evt():

case BLE_GATTS_EVT_HVN_TX_COMPLETE:
	tx_in_progress = false;

in main():

if(tx_in_progress == false)
	tx_in_progress = true
	ble_nus_string_send() 
	if error 
		tx_in_progress = false

RE: BLE connection lost after Flash write

Wei — Wed, 18 Sep 2019 14:04:28 GMT

Hi Kenneth:

Thanks for continuously supporting on this case.

I did do some search and read many cases online for this error. I tried adding the following or similar code to my project:

In on_ble_evt(ble_evt_t * p_ble_evt)

					case BLE_GATTS_EVT_HVN_TX_COMPLETE:
					tx_complete = true;
				//Add by Wei Lu
					break;

In main.c, coding like this:

						
						while(!tx_complete);
						err_code = ble_nus_string_send(&m_nus, value, bytes_to_send);
						if ((err_code != NRF_ERROR_INVALID_STATE)&& (err_code != NRF_ERROR_BUSY))
							{
								
								APP_ERROR_CHECK(err_code);
							}
						tx_complete = false;

Even do this way, the program still not not work. Further check shows the tx_complete not be set back to "True" after the first sending out setting to "False".

What's the possible reason for this? Do I use the BLE_GATTS_EVT_HVN_TX_COMPLETE correctly?

Thanks

RE: BLE connection lost after Flash write

Kenneth — Wed, 18 Sep 2019 08:28:03 GMT

Hi,

The error code 0x13 means that ble_nus_string_send() return NRF_ERROR_RESOURCES (see nrf_error.h). If you go into the implementation of ble_nus_string_send() you can find that it is the sd_ble_gatts_hvx() call that return this error code, and from the documentation of the softdevice api call you can find:

 * @retval ::NRF_ERROR_RESOURCES Too many notifications queued.
 * Wait for a @ref BLE_GATTS_EVT_HVN_TX_COMPLETE event and retry.

This is a normal error code that you need to handle as described.

RE: BLE connection lost after Flash write

Wei — Tue, 17 Sep 2019 22:17:37 GMT

Hi Kenneth:

Thanks for your kind reply.

I follow your instruction and set the breakpoint in the software, and find the error information, as follwoing:

So, the error happens in main.c, 0x04F1 (1265) line, which is the 108th line in my first attached main function code.

This is the error generated after BLE string sending:

err_code = ble_nus_string_send(&m_nus, value, bytes_to_send);

And the error info shows: auto- struct<untagged>.

Does this is some BLE connection error? How can this happens, and how can I fix it? Thanks

RE: BLE connection lost after Flash write

Kenneth — Tue, 17 Sep 2019 18:12:20 GMT

Add DEBUG as highlighted here (I used the example project from HID keyboard in SDK13.1 here, so other settings may differ from you):

Then it should be possible to set a breakpoint in app_error_save_and_stop().

RE: BLE connection lost after Flash write

Wei — Tue, 17 Sep 2019 16:44:37 GMT

I use Keil.

thanks

RE: BLE connection lost after Flash write

Kenneth — Tue, 17 Sep 2019 16:28:58 GMT

Are you using Segger Embedded Studio or Keil?

RE: BLE connection lost after Flash write

Wei — Tue, 17 Sep 2019 13:48:40 GMT

Hi Kenneth:

Thanks for prompt reply.

Can you kindly provide more information on how to catch the assert, and how to add DEBUG?

Thanks

RE: BLE connection lost after Flash write

Kenneth — Tue, 17 Sep 2019 12:45:46 GMT

It sounds to me that you have an assert in your application, which will by default reset the chip to recover. However during development it is useful to catch the assert, this can be done by define DEBUG in your project (preprocessor symbols), then you can find that in app_error_fault_handler() the code should run app_error_save_and_stop() instead of NVIC_SystemReset().

In app_error_save_and_stop() you should be able to identify the file name, line number and error code for the assert.