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8MBit Flash connected to TMS320C2834x (spraaw0)

Patrick Ruf
Genius 5095 points

Other Parts Discussed in Thread: TMS320C28346, TMS320C2834X

I would like to connect a 8MBit (512Kx16) flash to a TMS320C28346 device. For that reason I have downloaded the application spraaw0 which includes a sample schematic exacly for that case. If I compare that schematic to the XINTF reference guide (sprufn4a, chapter 2.7, please see picture) I think the sample schematic is wrong because address line XA0 (GPIO40) is not connected to the flash (like in a 32Bit data bus fashion). Now I'm a bit confused and don't know which of the two schematics is wrong.
Any ideas?

Thanks.

  • 0
    TI__Intellectual 2575 points

    The reference design makes only example. This considered the flexibility of various applications. For the F2833x/F2823x devices, XA0 and WE1 share a single pin. Thus, the XA0 is reserved on the reference design and use XA1 to XA19 as address bus. This reduces the efforts if user wants to expand the 16 bit flash memory to 32 bit flash memory. For custom design, you can also use XA0 to XA18 as bus.

  • 0 in reply to WeiGuo
    Genius 5095 points

    I just think that if I use Boot to external Flash (Jump to XINTF x16, Mode 9) on a TMS320C28346 device the example schematic does not work because XINTF works in 16 Bit mode and first fetches code from 0x100000 and then 0x100001 and so on. As the example schematics is for a DIM168 I expect that only TMS320C2834x devices are used (as the title on the sheet tells). 

  • 0 in reply to Patrick Ruf
    TI__Guru 60865 points

    You are correct that for TMS320C2834x for booting to XINTF the schematic is not appropriate.  Please follow the datasheet when making connections to your x16 external flash. 

     

    Wei correctly points out that the intention was to make transition between x16 and x32 designs simple.  However, this scheme can only work when using the external memory for data, not code.  This is not clear in the application note, which will be updated.       

  • 0 in reply to Devin Cottier
    TI__Intellectual 2575 points

    Thank Devin,

    As I mentioned that EVM reference design only shows an example. If you want to keep this layout you should pay attention to the address. Since zone6 has 2M(16bit) address, it’s also enough for (512kx16bit) Flash memory.

    Anyway, it’s better to follow the XINTF reference guide.

    Hopes this help.

    Cheers, 

    Wei 

  • 0 in reply to WeiGuo
    Genius 5095 points

    Now I'm ready to design the schematic.

    Thanks to all contributors.

    Best regards,

    Patrick