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c6000 emif Capacity

james camron
Prodigy 110 points

in c6416 EMIFA IS 64bit data Width & (3-23bit or 20bit) address Width.

2^20=1MBIT===> memory addressing capability !!!!------>((2^20)*64BIT)=64MBIT memory space & no 256Mbye space.Why is address lines is 3 to 23?Where is the addresses 0 to 2??are they internally connected??

but It has 4*CE with 1024MByte Addressable space(4*256Mbyte). How is it possible with 20 address lines???Is it really all that space is available?What is the meaning of 256MByte,how it is possible to do this with 20 address lines??

i want connect c6416 EMIFA to external sdram(4*32x*512k).acording to ((TMS320C6000 DSP External Memory Interface (EMIF) Reference Guide)) page 48 for 64MBit sram(4*32*512k) Addressable Space is 8Mbyte?What is the meaning of 8MBYTE??


Thank you  for your attention

  • 0
    TI__Guru* 84110 points

    James,

    The C6416 is a very capable device, but it is fairly old by now. Why are you starting a new design with this device?

    It appears to me that you are getting confused over TI terminology, and you are also confusing me by your terminology.

    james camron said:
    Why is address lines is 3 to 23?

    It is actually 3 to 22 from what I see in the datasheet. Are you finding 3 to 23?

    james camron said:
    Where is the addresses 0 to 2??are they internally connected??

    This should be made clear in the EMIF Reference Guide. If you have a wide device, you do not need to include address bits for the lower bytes because they are all brought into the DSP together.

    james camron said:
    It has 4*CE with 1024MByte Addressable space(4*256Mbyte). How is it possible with 20 address lines???

    The 4 CEn pins are each associated with a 256MB addressable region. If you had only one CE line for the whole 1GB region, it would be difficult to connect more than one type of device. For your convenience, we provide 4 CE pins to make it easier to connect multiple devices. I believe you need to look for the training material on our TI Wiki Pages to learn more basic information about these devices and how to use them. Please go to the TI Wiki Pages and search for "C6416 training" (no quotes); we have an old C6x1x workshop that will be very helpful to you.

    james camron said:
    What is the meaning of 256MByte,how it is possible to do this with 20 address lines??

    There is a difference between the size of an addressing region defined by the DSP's architecture and the size of an external component that is attached to the EMIF. Any DSP read or write to an address between 0x80000000-0x8FFFFFFF will be sent to EMIFA CE0 space, asserting CE0 and asserting address and control lines as defined/configured for that CE0 EMIF space. This does not mean you can use every byte of that address range, but only that for that address range those signals are available.

    james camron said:
    acording to ((TMS320C6000 DSP External Memory Interface (EMIF) Reference Guide)) page 48 for 64MBit sram(4*32*512k) Addressable Space is 8Mbyte?What is the meaning of 8MBYTE??

    I do not find the page 48 reference that you are making. Which revision of the EMIF Reference Guide are you using? What is the section number, section name, paragraph and line where you are referencing?

    4*32*512k = 64M

    64Mbit = 8MByte

    I do not understand what your question is.

    Regards,
    RandyP

  • 0 in reply to RandyP
    Prodigy 110 points

    RandyP

    Thank you for your  perfect answer.i understand it