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S25FL208K not responding | Cypress Semiconductor

S25FL208K not responding

Summary: 2 Replies, Latest post by dmv8086_1887316 on 26 Sep 2016 06:11 AM PDT
Verified Answers: 0
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dmv8086_1887316's picture
2 posts


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:


Please, could you help?


Sudheesh K's picture
Cypress Employee
41 posts

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? 


dmv8086_1887316's picture
2 posts

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,


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