src/pru.S

   1 /*
   2  * Copyright (c) 2016, Ian Sutton <ian@kremlin.cc>
   3  *
   4  * Permission to use, copy, modify, and/or distribute this software for
   5  * any purpose with or without fee is hereby granted, provided that the
   6  * above copyright notice and this permission notice appear in all
   7  * copies.
   8  *
   9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
  10  * WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
  11  * WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE
  12  * AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  13  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  14  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
  15  * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  16  * PERFORMANCE OF THIS SOFTWARE.
  17  */
  18
  19 .origin 0
  20 .entrypoint START /* used by debugger only */
  21
  22 #define PRU0_R31_VEC_VALID (1<<5)
  23 #define SIGNUM 3 /* corresponds to PRU_EVTOUT_0 */
  24
  25 #define DELAY_SECONDS 5
  26 #define CLOCK 200000000
  27 #define CLOCKS_PER_LOOP 2
  28 #define DELAYCOUNT DELAY_SECONDS * CLOCK / CLOCKS_PER_LOOP
  29
  30 START:
  31         MOV     r1, DELAYCOUNT
  32
  33 DELAY:
  34         SUB     r1, r1, 1
  35         QBNE    DELAY, r1, 0
  36
  37         /* intr */
  38         MOV     R31.b0, PRU0_R31_VEC_VALID | SIGNUM
  39         HALT
  40