[ECOS] Re: Atmel DataFlash commands?

[John Dallaway]

Hi Stano

Stanislav Meduna wrote:

> I am trying to interface with the Atmel DataFlash AT45DB642D
> (http://www.atmel.com/dyn/resources/prod_documents/doc3542.pdf)
> in the serial mode over the SPI. The current
> devs_flash_atmel_dataflash.c states
> 
> // Read commands opcodes
> #define DF_CONT_ARRAY_READ_CMD              0x68
> #define DF_MMEM_PAGE_READ_CMD               0x52
> #define DF_BUF1_READ_CMD                    0x54
> #define DF_BUF2_READ_CMD                    0x56
> #define DF_STATUS_READ_CMD                  0x57
> 
> However, these are _not_ what the datasheet of the part
> defines and e.g. the DF_CONT_ARRAY_READ_CMD actually
> returns wrong data (the bytes returned seem to be shifted
> 1 bit to the right)
> 
> According to the datasheet (and another working source I have
> access to) the correct commands in the serial mode are:
> 
> #define DF_CONT_ARRAY_READ_CMD              0xe8
> #define DF_MMEM_PAGE_READ_CMD               0xd2
> #define DF_BUF1_READ_CMD                    0xd4
> #define DF_BUF2_READ_CMD                    0xd6
> #define DF_STATUS_READ_CMD                  0xd7
> 
> This DF_CONT_ARRAY_READ_CMD works.
> 
> I have no access to other hardware using this or any other
> DataFlash, so I am not sure whether these defines actually
> work on other hardware.

Here's the datasheet for older revisions of the same part:

  http://www.datasheetcatalog.org/datasheet/atmel/DOC1638.PDF

It looks like the existing read command opcodes in the DataFlash driver
refer to an older SCK/CLK mode which is not supported in newer devices.
Can you determine whether we need to continue to support the old SCK/CLK
mode from the timing diagrams?

John Dallaway

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