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20 hours ago •
yne
yne
VCD file (Value Change Dump) command line viewer
Value Change Dump (.vcd) command line viewer for Windows, Linux and MacOS
# SKIP=13 vcd < samples/basic.vcd
global:
zoom: 2
date: Fri Nov 21 16:56:29 2014
total: 43
skip: 13
time:
scale: 1.00
unit: fs
line : "13 23 33 "
channels:
default:
e_clk : "╲▁╱▔╲▁╱▔╲▁╱▔╲▁╱▔╲▁╱▔╲▁╱▔╲▁╱▔╲▁╱▔╲▁╱▔╲▁╱▔╲▁╱▔╲▁╱▔╲▁╱▔╲▁╱▔╲▁╱▔"
e_rst : "▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔"
e_ren : "▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔╲▁▁▁╱▔▔▔╲▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁╱▔▔▔▔▔▔▔"
e_wen : "▁▁▁▁▁▁▁▁▁▁▁▁╱▔▔▔╲▁▁▁╱▔▔▔╲▁▁▁╱▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔"
e_d[3:0] : "3 3 4 4 5 5 Z Z 6 6 Z Z 7 7 Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z "
e_q[3:0] : "Z Z Z Z Z Z Z Z Z Z Z Z Z 3 3 Z Z 4 4 5 5 6 6 7 7 0 0 Z Z Z "
e_empty : "▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁╱▔▔▔▔▔▔▔▔▔▔▔▔▔"
e_mid : "▁▁╱▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔╲▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁"
e_full : "▁▁▁▁▁▁▁▁▁▁╱▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔╲▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁"
fifo1:
clk : "╲▁╱▔╲▁╱▔╲▁╱▔╲▁╱▔╲▁╱▔╲▁╱▔╲▁╱▔╲▁╱▔╲▁╱▔╲▁╱▔╲▁╱▔╲▁╱▔╲▁╱▔╲▁╱▔╲▁╱▔"
rst : "▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔"
ren : "▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔╲▁▁▁╱▔▔▔╲▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁╱▔▔▔▔▔▔▔"
wen : "▁▁▁▁▁▁▁▁▁▁▁▁╱▔▔▔╲▁▁▁╱▔▔▔╲▁▁▁╱▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔"
d[3:0] : "3 3 4 4 5 5 Z Z 6 6 Z Z 7 7 Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z "
q[3:0] : "Z Z Z Z Z Z Z Z Z Z Z Z Z 3 3 Z Z 4 4 5 5 6 6 7 7 0 0 Z Z Z "
empty : "▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁╱▔▔▔▔▔▔▔▔▔▔▔▔▔"
mid : "▁▁╱▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔╲▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁"
full : "▁▁▁▁▁▁▁▁▁▁╱▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔╲▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁"
w_adr[1:0] : "2 3 3 0 0 1 1 1 1 2 2 2 2 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 "
r_adr[1:0] : "1 1 1 1 1 1 1 1 1 2 2 2 2 3 3 3 3 0 0 1 1 2 2 3 3 3 3 3 3 3 "
Installation
From prebuilt binary
Manually download install a prebuilt binary
From sources
make
sudo make install
From Package Manager
Arch-based distribution:
yay -S vcd
Usage
vcd < in.vcd # output to screen
vcd < in.vcd > out.yml # output to file
vcd < in.vcd | less -S # scrollable view
Query
The default vcd output is a valid YAML file, so you can process it with many tools like yq (a jq for yaml)
# print the first 9 sample of the clk channel in the fifo1 scope
vcd < samples/basic.vcd | yq .channels.fifo1.clk[0:9]
Styling
Waveform, position, color can be customized using environment variables.
# skip the 9 first samples
SKIP=9 vcd < in.vcd | less -S
# Disable RAISE/DROWN transition
RAISE="" DROWN="" vcd < in.vcd
# color the bus value in green using StartTeX/EndTeXt (STX/ETX) variables
STX=$(printf "\x1b[32m") ETX=$(printf "\x1b[0m") vcd < in.vcd
Auto-Refresh
The following snippet endlessly wait for a change on the in.vcd file.
Then, when it happen, regenerate the out.yml graph and refresh the less -S out.yml scrollable display by sending a "R" keypress (for refreshing).
echo "hi ! please modify 'in.vcd' to refresh me" > out.yml
while inotifywait -q -e modify -e close_write in.vcd ; do
vcd < in.vcd > out.yml # regenerate out.yml
screen -x -r bridge -X stuff R # send Refresh command to foreground less -S
done & # this loop will run in background
screen -S bridge less -S out.yml # the foreground "less -S" display
# don't forget to stop the background loop using `kill %1` or fg + ^C
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