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Wait states configuration on TMS320C5517

Michelle Liu0
Prodigy 40 points

DSP C5517 has EM_WAIT2..5 pins to introduce wait states from external memories or I/Os. If I don't want to use these pins, can I assign wait states by programming? Assuming I can program wait states, is each different wait state associated with one chip select space(e.g. 2 wait stats for CS2, 3 wait states for CS3..), or I can assign different wait states(e.g. 2, 3 and 7 wait states) to different address ranges within one chip select(e.g. CS2)? And where can I find a document which has more details of programming wait states?

  • 0
    TI__Genius 12575 points

    Hi,

    EM_WAIT pins are inputs and has IPD - The IPD resistor on this pin can be enabled or disabled via the PUDINHIBR6  (1C4Fh) register.

    Also if not used this can be externally pulled down -  you could refer to C5517 EVM schematics.

    For programming details C5517 Technical reference   - http://www.ti.com/lit/ug/spruh16/spruh16.pdf   - EMIF section.

    Hope this helps.

    Regards

     Vasanth

  • 0 in reply to Vasantha K
    Prodigy 40 points

    Hi Vasanth,

    Thank you for your reply.

    I have some external devices which will need 2, 3 and 7 wait states from the DSP respectively. From what I read from the technical reference, in order to do this, I can only make physical connections from the devices to the EM_WAIT pins. Is my understanding correct? But instead, can I tell the DSP the number of wait cycles and which address range I want to assign my wait states by programming and leaving the EM_WAIT pins alone?

    Thank you in advance!

    Regards,

    Michelle

  • 0 in reply to Michelle Liu0
    TI__Genius 12575 points

    Hi Michelle,

    On your question on Physical connection to device, Yes that looks correct ,you could also refer to C5517 Schematics.

    From software programming looks there is no direct approach to do this, you would have also seen in C5517 TRM. But what is the reason for taking this approach ? Why not connect the wait pins and live EMIF to handle.

    Regards

     Vasanth