• AVR Freaks

What is meant by DATA0 and DATA1?

Author
Post
Essentials Only Full Version
__John
Starting Member
  • Total Posts : 66
  • Reward points : 0
  • Joined: 2012/04/10 01:44:12
  • Location: England
  • Status: offline
2012/07/12 06:39:09 (permalink)
0

What is meant by DATA0 and DATA1?

I keep reading about DATA0 and DATA1 but nowhare gives the meaning. It seems to be assumned that one knows.
 
What is meant by the terms DATA0 and DATA1?
 
 
#1

6 Replies Related Threads
    bytencoder
    Super Member
    • Total Posts : 363
    • Reward points : 0
    • Joined: 2009/06/25 12:30:07
    • Location: 0
    • Status: offline
    Re:What is meant by DATA0 and DATA1? 2012/07/12 08:55:21 (permalink)
    0
    You might want to check the USB specs ??
     

    8.4.3 Data Packets
     
    A data packet consists of a PID, a data field containing zero or more bytes of data, and a CRC as shown in
    Figure 8-7.  There are two types of data packets, identified by differing PIDs:  DATA0 and DATA1.  Two
    data packet PIDs are defined to support data toggle synchronization (refer to Section 8.6).

    #2
    newfound
    Super Member
    • Total Posts : 1840
    • Reward points : 0
    • Joined: 2003/11/07 12:35:49
    • Status: offline
    Re:What is meant by DATA0 and DATA1? 2012/07/12 09:08:30 (permalink)
    0
    bytencoder

    You might want to check the USB specs ??


    8.4.3 Data Packets

    A data packet consists of a PID, a data field containing zero or more bytes of data, and a CRC as shown in
    Figure 8-7.  There are two types of data packets, identified by differing PIDs:  DATA0 and DATA1.  Two
    data packet PIDs are defined to support data toggle synchronization (refer to Section 8.6).


     
    Wasn't so hard after all.... [image]app_themes/Classic/image/mIcons/m9.gif[/image]
    #3
    __John
    Starting Member
    • Total Posts : 66
    • Reward points : 0
    • Joined: 2012/04/10 01:44:12
    • Location: England
    • Status: offline
    Re:What is meant by DATA0 and DATA1? 2012/07/13 01:23:36 (permalink)
    0
     
    So, they are types of data packet, identified by different pid's. But I am still non the wiser.
    How do they differ? Why make the distinction? What is the significance of each type?
    Sorry to be a pain wink
    #4
    Antipodean
    Super Member
    • Total Posts : 1732
    • Reward points : 0
    • Joined: 2008/12/09 10:19:08
    • Location: Didcot, United Kingdom
    • Status: offline
    Re:What is meant by DATA0 and DATA1? 2012/07/13 01:31:14 (permalink)
    0
    __John 
    So, they are types of data packet, identified by different pid's. But I am still non the wiser.
    How do they differ? Why make the distinction? What is the significance of each type?
    Sorry to be a pain wink

    If you want to dig this deep into the 'how it works' then get a copy of Jan Axelsons book 'USB Complete'. You don't need the fourth edition (which is updated for USB3), so you should be able to get a third edition on Amazon for a reasonable price.
     
     

    Do not use my alias in your message body when replying, your message will disappear ...

    Alan
    #5
    bytencoder
    Super Member
    • Total Posts : 363
    • Reward points : 0
    • Joined: 2009/06/25 12:30:07
    • Location: 0
    • Status: offline
    Re:What is meant by DATA0 and DATA1? 2012/07/13 08:51:47 (permalink)
    0
    __John
      How do they differ? Why make the distinction? What is the significance of each type?

     
    No difference whatsoever.
    They are just sent alternatively, it is an extra safety-check if there are lost packets, and it is called data toggling (synchronization).
    It is used by all transfer types except isochronous (which uses only DATA0).
     
    Note: you have to handle this on the PIC SIE, via the DTS/DTSEN bits in BDxSTATUS.
    #6
    __John
    Starting Member
    • Total Posts : 66
    • Reward points : 0
    • Joined: 2012/04/10 01:44:12
    • Location: England
    • Status: offline
    Re:What is meant by DATA0 and DATA1? 2012/07/17 06:43:28 (permalink)
    0
    Many Thanks!!
    #7
    Jump to:
    © 2019 APG vNext Commercial Version 4.5