QSPI read fail.

[Justin_Yeh]

Hi Sir 

I try to write/read/earse any address with length 32. 

but some bytes shows zero "0x0" when I use , it should be 0xff after erasing...

Do you know what's the problem ? Thanks.

[00:00:30.151,791] <info> app: 0xFF
[00:00:30.151,798] <info> app: 0x0  //??
[00:00:30.151,804] <info> app: 0x0  //??
[00:00:30.151,810] <info> app: 0xFF
[00:00:30.151,816] <info> app: 0xFF
[00:00:30.151,822] <info> app: 0xFF
[00:00:30.151,829] <info> app: 0xFF
[00:00:30.151,835] <info> app: 0xFF
[00:00:30.151,841] <info> app: 0xFF
[00:00:30.151,847] <info> app: 0xFF
[00:00:30.151,856] <info> app: 0xFF
[00:00:30.151,862] <info> app: 0xFF
[00:00:30.151,868] <info> app: 0xFF
[00:00:30.151,874] <info> app: 0xFF
[00:00:30.151,881] <info> app: 0xFF
[00:00:30.151,887] <info> app: 0xFF
[00:00:30.151,893] <info> app: 0xFF
[00:00:30.151,899] <info> app:

[00:00:30.151,905] <info> app: 0xFF
[00:00:30.151,911] <info> app: 0xFF
[00:00:30.151,918] <info> app: 0xFF
[00:00:30.151,924] <info> app: 0xFF
[00:00:30.151,930] <info> app: 0xFF
[00:00:30.151,936] <info> app: 0xFF
[00:00:30.151,943] <info> app: 0xFF
[00:00:30.151,949] <info> app: 0xFF
[00:00:30.151,955] <info> app: 0xFF
[00:00:30.151,961] <info> app: 0xFF
[00:00:30.151,967] <info> app: 0xFF
[00:00:30.151,974] <info> app: 0xFF
[00:00:30.151,980] <info> app: 0x0  //?
[00:00:30.151,986] <info> app: 0x0  //? 
[00:00:30.151,992] <info> app: 0x0  //?

[haakonsh]

I think this is an issue where the addresses of your data are not word-aligned. 

I need access to your source code if I am to review it. 

[Justin_Yeh]

Yes, that's the root cause, Why data buffer must be aligned ? Could you help to explain this QSPI mechanism ?

Is this platform bug ? Thanks. 

[haakonsh]

From QSPI — Quad serial peripheral interface: 

Listed here are the main features for the QSPI peripheral:

• Single/dual/quad SPI input/output
• 2–32 MHz configurable clock frequency
• Single-word read/write access from/to external flash
• EasyDMA for block read and write transfers
• Execute in place (XIP) for executing program directly from external flash
• XIP execution speed: Up to 8 million instruction fetches per second for 16 bit instructions, up to 4 million instruction fetches per second for 32 bit instructions.

I think word-aligned address access is the standard for external flash chips. 

[Florian Zierer]

@haakonsh would it be possible to add an ASSERT in the SDK to check if the address is word aligned to e.g. nrfx_qspi_write and nrfx_qspi_read?

I had right now the same problem and it was really hard to find the cause of the problem.