Sending hexidecimal sensor data over BLE

[NikTheNordicUser]

Hi, Hope your are well, i am currently in the final part of my project where i am SPI Gyroscope float data from one nordic nrf52dk (S132) to another such that i can analyize the data from my PC. My only problem is that at the moment i am receiving the data rather slow (around 10ms per string using snprintf). The sensor i am using has configurable Output data rate and atm it is configured at 1000Hz thus my actual data rate is nothing close to that. I am certain that a majority of the issue lies that i am converting the sensor register output into a float such that i get the values directly and hence i am trying to remove this and send the hexadecimal registers directly as an array of 6 bytes (1 byte per register) such that in the SPI handler it will send the data and during the ble_send it will be gathering another set of data from the sensor. I belive that this should be the only way how to effeciently speed up the process and have all the data manipulation after it has been sent and received by BLE. May i please get some help as to how to do this. any help would be greatly appreciated as i have spent over a week trying this out on my own. 

Thanks in advance best regards

Nikolai Dimech 

[Jared]

Hi,

Are you using the SPIM or SPI peripheral? 

hence i am trying to remove this and send the hexadecimal registers directly as an array of 6 bytes (1 byte per register) such that in the SPI handler it will send the data and during the ble_send it will be gathering another set of data from the sensor.

Sending hex data can be done by using the NUS module, ble_nus_data_send() takes in a uint8_t array of length p_length. Which means that the functions takes in a byte array and sends it over BLE. See the ble_app_uart example if you need an example on how to use the NUS module.

regards

Jared 

[NikTheNordicUser]

spi perihperal and im  storing the registers in an array, may you plese provid me with some code to help me pls as ive tried many methods and couldnt manage

[NikTheNordicUser]

this is wat im trying to do, i am getting 6 register results and storing them in an uint8_t array called send#-buffer and i would like to send this using the ble_nus but when i run this nothing is sent

[Jared]

What is returned by ble_nus_data_send()? Also, what datatype is the Send_Buffer[] ? Is it a uint8_t array? If so, then you can omit the (uint8_t*) and just pass Send_Buffer as a parameter

[NikTheNordicUser]

i have solved the issue the problem was that i was providing a value for legnth. it had to be a pointer 

[NikTheNordicUser]

what is the maximum buffer size that the ble_nus_data_send can send at once please?

[Jared]

The max data length that can transferred over BLE with the NUS module is defined as:

 BLE_NUS_MAX_DATA_LEN (NRF_SDH_BLE_GATT_MAX_MTU_SIZE - OPCODE_LENGTH - HANDLE_LENGTH), where OPCODE_LENGTH is 1 and HANDLE_LENGTH is 2. NRF_SDH_BLE_GATT_MAX_MTU_SIZE is defined in the your sdk_config.h file.