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Non Volatile RAM (F-RAM & NVSRAM)

mbowen
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I am trying to read the Device ID from a CY15B104QN-50SXA chip and am getting out 0x402CC27F7F7F7F7F7F, which is the LSB to MSB read of the actual device ID listed in the datasheet, 0x7F7F7F7F7F7FC22C40. The datasheet claims the chip should read it out MSB to LSB, is there a reason this wouldn't be the case? Are other read/write operations affected as well?

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ritwicksharma
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Hi @mbowen,

 

In the case of device ID, the LSB byte, i.e., byte 0, shifts out first. I think you missed reading the Note part in the datasheet, so I have highlighted that part in the below image. Read and write operations should be MSB first.

 

ritwicksharma_0-1653530798830.png



I hope this answers your query.

Thanks,
Ritwick

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ritwicksharma
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Hi @mbowen,

 

In the case of device ID, the LSB byte, i.e., byte 0, shifts out first. I think you missed reading the Note part in the datasheet, so I have highlighted that part in the below image. Read and write operations should be MSB first.

 

ritwicksharma_0-1653530798830.png



I hope this answers your query.

Thanks,
Ritwick

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mbowen
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Hi Ritwick,

Thank you for the response. The note you have highlighted seems to contradict Figure 15 below the paragraph about Device ID reads. Can you confirm that the figure is in error, or is the note?

Thanks,

Max

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ritwicksharma
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Hi @mbowen,

 

I believe that is the most significant bit (MSB) of the least significant byte and the least significant bit (LSB) of the most significant byte.



Thanks,
Ritwick

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mbowen
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Hi Ritwick,

Thank you for that explanation, that would explain the behavior we are seeing. I would suggest Infineon update their datasheet to make it more clear that the figure refers to bits and not bytes.

Thanks,

Max

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