S25FL208K not responding

[Anonymous]

Hello,

   

I am developing an application where a microcontroller has to communicate with a s25fl208k memory by spi.

   

I have been trying to communicate with the not flash, so I power it up, configure the spi (100000 kbps, msb) and send the Read Manufacturer / Device ID (90h) command, but I always get no response (all 0s). I checked the SO line with the oscilloscope and it is always 0, no matter what spi polarity and phase I choose.

   

My pcb configuration is:

   

https://s11.postimg.org/aviict5cz/NOR.png

       

Please, could you help?

[SudheeshK]

What is the frequency at which you are accessing the device s25fl208k? Maximum frequency supported by this device is 76MHz. Can you please reduce the SPI frequency and try to read manufacturer ID and device ID? 

   

-Sudheesh

[Anonymous]

Hello Sudheesh,

   

Eventually I connected a logic analyzer and realized that the CS line was going up and down every byte I sent to the memory, so the command was not executing, and the flash chip not responding.

   

Now I set CS line low for the whole command and it works.

   

Thanks for your support,

   

Daniel