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Adventurer
Adventurer
1,655 Views
Registered: ‎03-04-2018

"Ambiguous Clock In Event Control" synthesis error

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Hi guys,  I've been getting the synthesis error in the subject title for a particular block (see below).

 

I understand that the error comes about when the sensitivity list of the always block makes it so that the synthesis tool is not sure how to connect things (as discussed here and here). However I cannot tell what is wrong in my case.

 

I've been using "always @(posedge clk or posedge rst)" all across my design and am only seeing the error on this very particular block. Can anybody tell me where I have erred? Thanks!

 

    always @(posedge clk or posedge rst) begin
        if (rst) begin 
            frame1 <=  46'h1490416637ff;
            frame1_counter <= 'd46;
            frame1_start <= 0;
            frame1_end <= 0;
            frame1_out <= 1;
        end
        begin
            if (tx_en) begin
                if ((frame1_counter != 0) && transmit_point_reached) begin
                    frame1 <= {frame1[44:0], 1'b0};
                    frame1_counter <= frame1_counter - 1;
                    frame1_start <= 1;
                end
                else if (frame1_counter == 0) frame1_end <= 1;
                
                if (transmit_point_reached) frame1_out <= frame1[45];
             end
             

        end   
    end

 

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Guide
Guide
2,016 Views
Registered: ‎01-23-2009

Re: "Ambiguous Clock In Event Control" synthesis error

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You are missing the "else" between the "end" of your reset clause and the "begin" of your non-reset clause...

 

Avrum

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3 Replies
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Guide
Guide
2,017 Views
Registered: ‎01-23-2009

Re: "Ambiguous Clock In Event Control" synthesis error

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You are missing the "else" between the "end" of your reset clause and the "begin" of your non-reset clause...

 

Avrum

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Moderator
Moderator
1,586 Views
Registered: ‎07-21-2014

Re: "Ambiguous Clock In Event Control" synthesis error

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@silverace99work 

 

Let us know if you have any further queries, else please close this thread by accepting above answer as an accepted solution.

 

Thanks

Anusheel

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Adventurer
Adventurer
1,580 Views
Registered: ‎03-04-2018

Re: "Ambiguous Clock In Event Control" synthesis error

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Ahh, derp. Thanks avrumw!

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