Re: connecting McBSP to external devices

             Hi to all,

                     I have had the same problem a few weeks ago, but with 6713 boards. What I have done is to connect the next pins:

                [A: device that transmit]

                [B: device that receive]

                 A----------------------->B

         DX0 from A ---------> DR0 from B

         FSX from A ---------> FSR from B

         CLKX from A -----------> CLKR from B

         GND from A ------------> GND from B

                  With this four pins, the communication works fine, although I am now adjusting some sychronism problems. You can also connect the pins in the other direction (B ---------------->A) and decide which transmits and which one receives including in the source code a sentence like: if(DSK6713_DIP_get(0)==1){}
                                                              else{}

                  I am trying to do the communication between the boards with radio-transceivers, so I may use some answers of this topic (thanks in advance).

                   Anything else, please post it. 

         Pablo L.

From: d...@yahoo.com
Reply-To: d...@yahoo.com
To: c...
Subject: [c6x] Re: connecting McBSP to external devices
Date: Mon, 30 Apr 2007 14:01:49 -0400

hello all,
i'm new to using the dsp , so i need help in my graduation project ... i have 2 c6416 dsps i want to interface between them through the mcbsp i know i'll need to connect the dxo to dro so is there anything else i need to connect for this to work , aslo wht kind of wire do i use ? do u have any other ideas about the connection , i really could need ur help thanks alot ..
hoda
Joshy-
>
>> that is ,
>> all the divice will share comman DX pin and each device will take
>> their share according to the clock signal?
>
>Yes. In TDM mode, each device transmits on DX pin *only* during it's time-slot, and
>otherwise tri-states the pin. This allows pin to be shared by multiple devices.
>Note that each device needs to de-activate (tri-state) very quickly so as not to
>interfere with the next time-slot device.
Not being quick enough leads to
>contention, which is one reason that TDM mode is a limited scheme for shared bus
>communication, with rates less than 25 MHz typical.
>
>On receive (DR pin), each device "listens" during its time-slot, although nothing
>prevents devices from listening to multiple time-slots.
>
>-Jeff
>
>>
>> On 24/01/07, Jeff Brower wrote:
>> > Joshy-
>> >
>> >
>> > > that means , it will be time division multiplexed through single , dx and
>> > dr pins?
>> > > then i think there is a need of external circuitary to identify the
>> > corresponding
>> > > slots of the time division signal and enabling corresponding signal? which
>> > pin out
>> > > is used as the identifier to
different time slots?
>> >
>> > No external pin is needed. The TDM state machine inside the TI DSP uses the
>> > framesync pulse to indicate start of frame, then clock to count number of
>> > bits per
>> > word and number of time-slots (words). Time-slots per frame is programmable
>> > in the
>> > McBSP registers. So it's up to you when connecting and programming external
>> > devices
>> > (including other DSPs, if needed) to make sure all devices sharing a TDM
>> > channel
>> > agree on number of time-slots per frame.
>> >
>> > -Jeff
>> >
>> >
>> > > On 24/01/07, Jeff Brower wrote:
>> > >
>> > > Joshy-
>> > >
>> > > > how to
connect the McBSP to multiple channels?
>> > > > there is only one DX and DR in McBSP then how can it be connected
>> > to
>> > > different channels?
>> > >
>> > > Search the C6000 series McBSP reference guide (SPRU580a.pdf) for
>> > "TDM".
>> > >
>> > > -Jeff
>
>

---

Coches nuevos, coches de ocasi, coches de Km 0 Si piensas en cambiar de coche, MSN Motor.
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