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SparkyNZ's avatar
SparkyNZ
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4 years ago

Help with VJTAG and TCL script

I must be doing something really stupid here.

The problem I have is that I seem to have a disagreement between instruction register values in TCL script and in Verilog.

In TCL:

set RESET_HI_CMD 11
set RESET_LO_CMD 12
..
device_virtual_ir_shift -instance_index 0 -ir_value $RESET_LO_CMD
setJTAGBypass
after 3000
device_virtual_ir_shift -instance_index 0 -ir_value $RESET_HI_CMD
setJTAGBypass

In Verilog:

localparam RESETHI = 4'b1011; // Definitely 11, same as TCL
localparam RESETLO = 4'b1100; // Definitely 12, same as TCL..

if( opco[3:0] == RESETLO)
begin
notReset <= 0;
oLED1 <= 0;
oLED8 <= ~ oLED8;
end
else
if( opco[3:0] == RESETHI)
begin
notReset <= 1;
oLED1 <= 1;
oLED7 <= ~ oLED7;
end

What I'm observing is a sequence of RESETHI-(3 seconds)-RESETLO on my device when it SHOULD be RESETLO-(3 seconds)-RESETHI

Any ideas please?

5 Replies

    • SparkyNZ's avatar
      SparkyNZ
      Icon for Contributor rankContributor
      4 years ago

      @YuanLi_S_Intel is this what you would expect to see?

      Info (262019): Equivalent device ir and dr shift commands
      Info (262020): device_dr_shift -length 12 -dr_value 00B -value_in_hex
      Info (262020): device_dr_shift -length 12 -dr_value 40C -value_in_hex

      (3 second delay)
      Info (262019): Equivalent device ir and dr shift commands
      Info (262020): device_dr_shift -length 12 -dr_value 00B -value_in_hex
      Info (262020): device_dr_shift -length 12 -dr_value 40B -value_in_hex

      I'm assuming the 40C corresponds to my RESET_LO_CMD (12) and 40B corresponds to RESET_HI_CMD (11) ?

      • SparkyNZ's avatar
        SparkyNZ
        Icon for Contributor rankContributor
        4 years ago

        @YuanLi_S_Intel there must be something wrong with my design. I've been struggling with this for weeks now.

        I expect to see LED8 toggle, followed by LED7 toggle (RESETLO, 3 seconds, RESETHI). But what I see is the opposite (LED7 toggle= RESETHI, 3 seconds, LED8 toggle=RESETLO)

        Am I not using uir correctly?

        The full project can be found here: https://github.com/SparkyNZ/FixReset


  • YuanLi_S_Intel's avatar
    YuanLi_S_Intel
    Icon for Regular Contributor rankRegular Contributor
    4 years ago

    I am glad it is solved now.


    Meanwhile for the TCK frequency, it affects the speed of communication using JTAG. You may put higher frequency to increase the speed. However, too high will cause communication issue as well. You can try and find the optimum speed for your case.