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C6670 VCP2 configuration

g.f.
Guru 15510 points

Hi,

I have questions about C6670 VCP2.

Question 1.

Do I need to perform any configuration for VCP2 after completion of first decode process and  before starting the next decode process?

Question 2.

I want to know in what kind of case "Output parameters" should be transfer?

In VCP2 User Guide(sprugv6a) page. 50 Table 4-1, it said "Output parameter" is optional.

Should I transfer "Output parameters"?

Question 3.

There are 4 VCP2 instances on C6670.

Right now we are using 1 VCP2 instances from Core0. VCP2 are processing 30 Data blocks but I want to reduce the processing time. So, I'd like to make processing disperse using 4 VCP2 from one core. Is it available to use all 4 VCP2 instances from only one core?

best regards,

g.f.

  • 0
    TI__Guru* 81335 points

    Hello g.f,

    I am working with expert to answer this post, please refer below thread which may help you.

  • 0 in reply to Raja
    TI__Mastermind 30405 points

    Hi g.f.

    Sorry for the delayed response. Please find the answers given below in order:

    1. Referring to chapter-3 of the VCP2 user's guide, VCP2 configuration consists of both one-time and per-block configuration registers. The VCP2 Input config registers (VCPIC0 to VCPIC5) are sent to the VCP on a per-block basis.  The only register which is configured once at init time is the Endian mode register (VCPEND) as given in section 3.12. The EDMA configuration is also programmed once until the VCP2 is reset.

    2. The transfer of output parameters depends upon the OUTF bit in VCPIC5 (section 3.8). Output parameters are defined in section 4.4. The OUTF bit in VCPIC5 indicates whether the VCP should generate a VCPREVT for reading the output parameters. The OUTF bit setting will impact the EDMA3 programming (see Section 4.2.2.3).

    3. There is no restriction that relates to using specific VCP2 instances with specific dsp cores. You should be able to use all 4 VCP2s from the same core.
     
    Regards
    -Nitin 

  • 0 in reply to Nitin Sakhuja
    Guru 15510 points
    Hi Nitin,

    Thank you for the reply and sorry for the delay.

    I read the Section 4.4 of VCP2 User guide, but I don't understand I should transfer "Output parameter" or not.
    How should I judge Output parameter transfer are needed or not?

    best regards,
    g.f.
  • 0 in reply to Nitin Sakhuja
    Guru 15510 points
    Hi Patrick,

    I'm sorry, I have additional question about the answer#1 which you send.

    I understood that VCPIC0 to VCPIC5 are sent to the VCP on per-block basis.
    But if same value of previous VCPIC0 to VCPIC5 register are used for the next block,
    do I need to perform configuration for these registers after completion of first decode process and before starting the next decode process?

    best regards,
    g.f.
  • 0 in reply to g.f.
    TI__Mastermind 30405 points

    Hi g.f.

    Please find the answers to your follow-up questions as given below:

    1. Output parameters: VCP output parameters consist of two 32-bit words namely the registers VCPOUT0 and VCPOUT1.

    VCPOUT0 provides the FMAXS and FMINS bits which indicate the final maximum and minimum state metric values, respectively. VCPOUT1 provides the FMAXI bit which indicates the state index for the state with the final maximum state metric. In addition to that, VCPPOUT1 provides the Yamamoto bit which can be used as a binary frame quality indicator for the decoded frame. The user needs to enable Yamamoto logic using the YAMEN bit in VCPIC1 and provide the corresponding threshold value bits using YAMT bit field in VCPIC1 as defined in section 8.2.

    The output parameters can be used to figure out the decoding quality. It upto the application whether it wants to use the VCP output parameters and accordingly, set the OUTF bit in VCPIC0.

    2. The first transmit event (VCPXEVT) that the VCP generates is to transfer the input configuration words for the channel, using EDMA.  Therefore, by design, VCP2 expects input configuration words for every block. As part of programming the VCP2 EDMA resources, the Input Config Transfer (upon completion) is linked to the EDMA for branch metrics transfer.

    Regards
    -Nitin

  • 0 in reply to Nitin Sakhuja
    Prodigy 10 points
    hi ,
    I am new to this field ,i have a soft decision and hard decision example code for dsk6455 ,its runnig successfully but i didnt understand from where it is taking input .thanks in advance
  • 0 in reply to Arun kumar51
    TI__Guru* 81335 points
    Hi Arun kumar,

    We recommend you to create new thread for the new queries. Please do not follow up on old threads because it gets less attention than new.

    Thank you.