• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 1 answer
  • Subscribers 16 subscribers
  • Views 959 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Re: Issue in CC2545 Point to many communication

manikanta kolisetty
Expert 1425 points
Other Parts Discussed in Thread: CC2545

Hi all,

I kept one cc2545 device as central beacon. and 3 cc2545 devices as normal transceivers.

I kept same address entry and address and frequency and mode for both central beacon and transceivers as follows:

In this above case requests from central beacon was reaching to all devices and but beacon was taking the only one acknowledgement from the devices of same address transceivers.

Could you please anyone give the information why it was happening?

  • 0
    TI__Mastermind 36375 points

    What software are you using?

    If it is the streaming protocol we have been discussing for some time, then it is because the the software was not designed for point to multipoint communication. The central node will send a message, all three receivers might (or might not ) hear the message. Then they will all three respond with an ACK at the exact same time. This will create collisions in the air and it will not work. For point to multipoint you need to not perform ACK's or you need to implement variable time delay for each ACK.

    /TA

  • 0 in reply to TA12012
    Expert 1425 points

    Hi TA12012,

    I am using the IAR embedded work bench IDE.

    I was configured all the devices in auto mode. I think there was no option for using of Streaming protocols. I observed the following protocols in user manual:

    In the above protocols I was used auto mode 10 bit header for all 4 devices as following as explained in before post:

    I was separating the one byte in acknowledgement packet of every device. like (0x01,0x02,0x03 for first ,second, third device simultaneously).

    At central beacon when I received ack packet with 0x01 byte I will confirm that the ack was given by first device. simultaneously for remaining two devices.

    I was kept same address id for central beacon and three devices as shown in above pic.

    In this case when the central beacon sends request t the device. the request was reaching to all three devices because I was kept same address for three devices.

    But when I am sending ack from three devices, the central beacon was receiving only one packet of any one device.

    1)why it was happening in this case?

    2)what I have to do to develop the streaming protocol with this cc2545 sir?

  • 0 in reply to TA12012
    Expert 1425 points

    Remainder:

    In reply to TA12012:

    Hi TA12012,

    I am using the IAR embedded work bench IDE.

    I was configured all the devices in auto mode. I think there was no option for using of Streaming protocols. I observed the following protocols in user manual:

    In the above protocols I was used auto mode 10 bit header for all 4 devices as following as explained in before post:

    I was separating the one byte in acknowledgement packet of every device. like (0x01,0x02,0x03 for first ,second, third device simultaneously).

    At central beacon when I received ack packet with 0x01 byte I will confirm that the ack was given by first device. simultaneously for remaining two devices.

    I was kept same address id for central beacon and three devices as shown in above pic.

    In this case when the central beacon sends request t the device. the request was reaching to all three devices because I was kept same address for three devices.

    But when I am sending ack from three devices, the central beacon was receiving only one packet of any one device.

    1)why it was happening in this case?

    2)what I have to do to develop the streaming protocol with this cc2545 sir?

    As you said in previous post if the 3 devices sends ACK to central receiver at a same time. collision will occurs surely.

    How we can over come this sir?

    Is there any mechanism available in this chip to overcome this sir?(like CDMA etc..)