Not able to write and read more than 16KB data in the qspi memory on nrf52840

[Rajat]

Hi everyone

I have been reading the GPS data using nordic nrf52840 over the UART. 
I am able to receive as much as 64KB of data via the UART.
Here's the scenario of whats been happening

1. If i Write the data to QSPI memory and not read it back after writing , everything works fine. I am able to write the 64KB of data to the memory.
2. If i write the data to QSPI memory and read it back after writing is finished , I am not able to read the data , the software get paused saying , unknown function at 0x000000978
3. If i write and read data less than 16KB on the QSPI , everything works fine . 

In a summary
If i write more than 16KB of data to qspi memory and read it back , software stops abruptly and says "unknown function at 0x000000978"
Help needed urgently , kindly suggest some solutions 

Thanks
Rajat 

[Rajat]

Correction : 

2. If i write more than 16KB data to QSPI memory and read it back after writing is finished , I am not able to read the data , the software get paused saying , unknown function at 0x000000978

[Edvin]

Hello,

When you use nrf_drv_qspi_write(m_my_buffer, MY_DATA_SIZE); what is the buffer size of m_my_buffer, and what is MY_DATA_SIZE?

somewhere you have initialized m_my_buffer[n]. What is n?

Perhaps you can show me how you use nrf_drv_qspi_write and read? However, it sounds like some buffer overflow. Does this also happen if you do not use the softdevice (Just for testing and root cause investigation)?

What HW do you use? Is it the nRF52840 DK? Or is it custom HW? If it is custom, what external QSPI flash do you use?

Best regards,

Edvin

[Rajat]

MY_DATA_SIZE is 65532 and Hardware is quectel bg-96(based on nrf52840) with the same qspi memory as the nrf52 PDK. 
Chip Name is MX25R6435F

[Rajat]

If it were a buffer problem , it would have also occured when i do only the writing the data. 
But problem arises only when i try to read it back after writing

[Rajat]

Correct me if i am wrong
Disable function for the softdevice is used is this one 
https://infocenter.nordicsemi.com/index.jsp?topic=%2Fcom.nordic.infocenter.s140.api.v6.0.0%2Findex.html&cp=4_5_3_4
But it doesn't help , same problem