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TMS320F28386D-Q1: Total number of inputs possible for CLB block

Part Number: TMS320F28386D-Q1

I have 36 GPIO inputs that I want to provide as an input to 6 CLB tiles via input XBAR and CLB XBARs. But there are only 16 input XBARS available. Am I missing something in the configuration or the total no of inputs provided by the INPUTXBAR is limited to 16?

  • For this device specifically, you HAVE A NEW PERIPHERAL NAMED "CLB INPUT XBAR". You can use that to take 16 inputs to the CLBs. Thats going to need 2 CLBs, 8 input each.

    Then you have INPUTXBAR + CLB XBAR which can do another 8 signals. 

    Thats max I believe.


  • Hi Nima,

    Thanks for the reply. I got your point regarding combining both CLB INPUT XBAR and Input X-BAR + CLB X-BAR. But you said INPUTXBAR + CLB XBAR can do another 8 signals. In the TRM document, INPUT 1 to 16 are available for INPUT X-BAR with CLB X-BAR as the destination for INPUTs 1 to 14. Also, in the syscfg, I was able to configure 16 inputs(not 14) for the Input XBAR.

    But in the GPIO to CLB Tile Connections figure in the CLB section, only Inputs 1 to 6 are shown between Input X-BAR and CLB X-BAR, and in the Input X-BAR diagram in the Crossbar section, only the inputs 1 to 6 are connected to Output X-BAR. Which is correct?

    My understanding is that I can use 16 Inputs from the CLB INPUT XBAR across 2 or 3 tiles as required for my application. Additionally, I can use 16 more inputs from Input X-BAR + CLB X-BAR creating AUX signals(max 8, is this what you meant by 8?) which are the combination of these input signals, to become the input of another 2 or 3 tiles.

    For this, I need to know whether the issues I mentioned in the TRM are correct.

  • There are only 8 CLB XBAR outputs.



  • Clearly, you are talking about the output from CLB XBAR, while I was talking about the maximum no of possible GPIO inputs to Input XBAR. I am assuming it is 16, even though in the GPIO to CLB Tile Connections figure in the CLB section, only Inputs 1 to 6 are shown between Input X-BAR and CLB X-BAR.  I wanted clarity on this point. So, my question is can I provide 16 GPIO inputs to the input XBAR? I understand that these 16 inputs become 8 aux outputs coming out of CLB X-BAR.

  • 1. Yes you can have 16 GPIOs are input to INPUTXBAR.

    2. There are 16 outputs out of the INPUTXBAR.

    3. The CLB XBAR has 8 ouptuts and acess to 10 INPUT XBAR outputs

    4. All 8 output of the CLB XBAR are available at CLB muxes.


  • Thank you for the reply.

    Regarding point 3, I think you meant 14 INPUT XBAR outputs.

  • I only see 10 in the table image i sent you!


  • Hi Nima, I am not able to reply to your latest comment. I am unable to attach an image. If you check the possible values for Mux 0- 7, 4 more Inputs are possible. The table you attached is incomplete. Also, I want to let you know that in Figure 9-5. GPIO to CLB Tile Connections, INPUT1 - INPUT6 is shown between Input X-BAR and CLB X-BAR(instead of 14).

  • Oh yes, sorry I missed the rows 0 to 7. You are correct.