NAME

       pig2vd - A utility to convert pigpio notifications to VCD.

SYNOPSIS

       pig2vcd </dev/pigpioXX >file.VCD

DESCRIPTION

       pig2vcd is a utility which reads notifications on stdin and writes the output as a Value
       Change Dump (VCD) file on stdout.

       The VCD file can be viewed using GTKWave.

   Notifications
       Notifications consist of 12 bytes with the following binary format.

       typedef struct
       {
          uint16_t seqno;
          uint16_t flags;
          uint32_t tick;
          uint32_t level;
       } gpioReport_t;

       seqno: starts at 0 each time the handle is opened and then increments by one for each
       report.

       flags: two flags are defined, PI_NTFY_FLAGS_WDOG and PI_NTFY_FLAGS_ALIVE. If bit 5 is set
       (PI_NTFY_FLAGS_WDOG) then bits 0-4 of the flags indicate a gpio which has had a watchdog
       timeout; if bit 6 is set (PI_NTFY_FLAGS_ALIVE) this indicates a keep alive signal on the
       pipe/socket and is sent once a minute in the absence of other notification activity.

       tick: the number of microseconds since system boot. It wraps around after 1h12m.

       level: indicates the level of each gpio. If bit 1<<x is set then gpio x is high. pig2vcd
       takes these notifications and outputs a text format VCD.

   VCD format
       The VCD starts with a header.

       $date 2013-05-31 18:49:36 $end
       $version pig2vcd V1 $end
       $timescale 1 us $end
       $scope module top $end
       $var wire 1 A 0 $end
       $var wire 1 B 1 $end
       $var wire 1 C 2 $end
       $var wire 1 D 3 $end
       $var wire 1 E 4 $end
       $var wire 1 F 5 $end
       $var wire 1 G 6 $end
       $var wire 1 H 7 $end
       $var wire 1 I 8 $end
       $var wire 1 J 9 $end
       $var wire 1 K 10 $end
       $var wire 1 L 11 $end
       $var wire 1 M 12 $end
       $var wire 1 N 13 $end
       $var wire 1 O 14 $end
       $var wire 1 P 15 $end
       $var wire 1 Q 16 $end
       $var wire 1 R 17 $end
       $var wire 1 S 18 $end
       $var wire 1 T 19 $end
       $var wire 1 U 20 $end
       $var wire 1 V 21 $end
       $var wire 1 W 22 $end
       $var wire 1 X 23 $end
       $var wire 1 Y 24 $end
       $var wire 1 Z 25 $end
       $var wire 1 a 26 $end
       $var wire 1 b 27 $end
       $var wire 1 c 28 $end
       $var wire 1 d 29 $end
       $var wire 1 e 30 $end
       $var wire 1 f 31 $end
       $upscope $end
       $enddefinitions $end

       The header defines gpio identifiers and their name.  Each gpio identifier must be unique.
       pig2vcd arbitrarily uses 'A' through 'Z' for gpios 0 through 25, and 'a' through 'f' for
       gpios 26 through 31.  The corresponding names are 0 through 31.

       The VCD file may be edited to give a frendlier name, e.g. 8 could be changed to ENCODER_A
       if an encoder switch A is connected to gpio 8.

       Following the header pig2vcd takes notifications and outputs a timestamp followed by a
       list of one or more gpios which have changed state.  The timestamp consists of a '#'
       followed by the microsecond tick.  The state lines contain the new state followed by the
       gpio identifier.

       #1058747
       0H
       0I
       #1059012
       1H
       #1079777
       1I
       #1079782
       0I
       #1079852
       1I
       #1079857
       0I
       0H
       #1165113
       1H
       #1165118
       0H
       #1165153
       1H

SEE ALSO

       pigpiod(1), pigs(1), pigpio(3), pigpiod_if(3), pigpiod_if2(3)

AUTHOR

       joan@abyz.me.uk