Prepare Write Request

[Milan]

Hi Team,

Is there any example to understand Prepare Write Request/Prepare Write Response?

In ble_uart_app example, I am getting p_ble_evt->header.evt_id = 2 if I put printf in default case in on_ble_evt function.

Regards,

Milan Joshi

[shibshab]

Is it S110 or S120 you are working with?

My recommendation would be to look at the SDK documentations Message Sequence Charts first. If you want automated control (the simplest appproach) you let the softdevice take care of the data copying. NOTE: In this case you need a buffer bigger than the data you are going to hold! ceil(BUF_SIZE/18)*24 + 2 would be a sufficient size for the buffer in this case.

[Milan]

Hi shibshab,

Tried what you suggested and it worked but in the end it give error shown in snap below. any idea?

following is the part of the code that I have tried for this:

uint8_t data[1024];
ble_user_mem_block_t *mydata;
mydata->p_mem = data;
mydata->len = 1024;
err_code = sd_ble_user_mem_reply(m_conn_handle, mydata);

[shibshab]

First of all you should use the nRF-Sniffer. Its easier to get an overview with, and it uses Wireshark, so you can just send the log files instead of having to do screenshots.

Anyway, what value have you set for the length of the characteristic? The ble_gatts_attr_t.max_len can not be bigger than 512.

[Milan]

Hi Shibshab,

ble_gatts_attr_t.max_len was 20 and I increased it to 512 and error of att length is resolved now!! Thank you very much!!

Regards, Milan Joshi

[Milan]

Hi, shibshab,

Last query!! all the data received during this queued approach will be there in the provided data[1024]?

When I print 512 bytes of data buffer I get only few!!

Is this the problem like printf debug is not getting printed fully?

[shibshab]

If you debug your application, and inspect the content of your buffer when receiving the EXEC_WRITE_OP event, you should see this. If no error is reported, the entire value should be there.