shirriff

 // This DTS overlay sets up one input and one output pin for use by  
 // PRU0 via its Enhanced GPIO mode, which will let us access those pins  
 // by writing to R30 bit 15 or reading from R31 bit 14.  
   
 // Save this file wherever you want (but I recommend /lib/firmware), as  
 // "PRU-GPIO-EXAMPLE-00A0.dts".
   
 // Compile with:
 // dtc -O dtb -I dts -o /lib/firmware/PRU-GPIO-EXAMPLE-00A0.dtbo -b 0 -@ PRU-GPIO-EXAMPLE-00A0.dts  
   

shirriff

import math

# 8087 tangent algorithm, from Implementing Transcendental Functions, R. Nave

atan_table = [math.atan(2 ** -i) for i in range(0, 17)]

def cordic_tan(z):
  # Compute tan of angle z, using CORDIC
  q = []
  # Break down z into sum of angles, where each angle is 0 or atan(2**-i)

shirriff

# Crack Xerox Alto disk passwords using math.

import sys

def findPasswd(passvec):
  # a and b are the salt values
  a = (passvec[1] << 16) + passvec[2]
  b = (passvec[3] << 16) + passvec[4]
  if a == 0 or b == 0:
    print 'No password'

shirriff

-                                                                               
-     *                                                                         
-                  +                                  XX                        
-                              +             X      XXXX                        
-           +                               XXX    XXXXX                        
-                   *                    XXXXXX  XXXXXXX                        
-                                XX    XXXXXXXXXXXXXXXXX                        
-                              XXXX   XXXXXXXXXXXXXXXXXX                        
-       *                     XXXXXX XXXXXXXXXXXXXXXXXXX                        
-                XX        XXXXXXXXXXXXXXXXXXXXXXXXXXXXX                        

shirriff

# https://www.reddit.com/r/puzzles/comments/1hjpd63/comment/m38k73k
# Port of my Arc program at https://www.righto.com/2010/12/solving-edge-match-puzzles-with-arc-and.html
# Ken Shirriff righto.com

import math

# Symbols
menorah = 1
dreidel = 2
gift = 3

shirriff

d0  STR-0     Store the next byte (7) in register 0.
07
0c  SLE       Skip two instructions if accumulator <= register 0.
03  DED       Decrement the accumulator in decimal mode
5f  NOP       No operation
d0  STR-0     Store the next byte (0x31) in register 0
31
30  SBZ-0     Skip two instruction bytes if accumulator bit 0 is zero
81  JMP-1     Jump to 0x1c9 (end of this code block)
c9

shirriff

# Program to parse VGA data (EDID) accessed from I2C device 0x50
#
# This is a quick demo not a supported program, so don't expect
# correctness from it.
#
# Edid format from:
# https://en.wikipedia.org/wiki/Extended_Display_Identification_Data#EDID_1.4_data_format
#
# Ken Shirriff  http://righto.com

shirriff

/*
 * Demonstration of the BeagleBone's PRU, using a timer.
 * Ken Shirriff, http://righto.com
 */
#include <stdint.h>

#define DELAY_NS 100 // Use 500000000 for 0.5 second delay
#define WRITE_PIN 15 /* P8_11, Ethernet output data, pr1_PRU0_pru_r30_15 */

// PRU Interrupt control registers

shirriff

# This code prints out the melody in the UM66T sound chip's ROM.
# The ROM holds Jingle Bells, Santa Claus is Coming to Town, and We Wish You a Merry Christmas. 
# See this Twitter thread for details: https://twitter.com/kenshirriff/status/1472297415201869831

from collections import defaultdict

notes = ['X', 'X', 'G4', 'A5', 'B5', 'C5', 'D5', 'E5', 'F5', 'G5', 'A6', 'B6', 'C6', 'X', 'X', 'X']

# Hard-coded ROM contents.
bits = {"24,1":0,"15,0":1,"15,1":0,"15,3":1,"15,4":0,"14,4":1,"13,4":0,"12,4":1,"11,4":0,"10,4":1,"9,4":1,"8,4":0,"7,4":0,"6,4":1,"5,4":1,"4,4":0,"0,4":0,"1,4":1,"2,4":1,"3,4":0,"0,1":1,"0,0":1,"3,0":1,"4,0":1,"7,0":1,"8,0":1,"11,0":1,"12,0":1,"17,0":1,"19,0":1,"20,0":1,"23,0":1,"25,0":1,"26,0":1,"29,0":1,"31,0":1,"30,1":1,"28,1":1,"26,1":1,"25,1":1,"22,1":1,"21,1":1,"18,1":1,"17,1":1,"30,5":1,"31,6":1,"30,8":1,"30,9":1,"30,10":1,"31,11":1,"31,13":1,"31,14":1,"30,15":1,"31,16":1,"30,18":1,"30,19":1,"31,20":1,"31,21":1,"30,23":1,"31,24":1,"31,25":1,"31,26":1,"31,28":1,"30,29":1,"30,28":0,"29,

shirriff

#!/usr/bin/python

""" Download an IR remote signal from a Rigol DS1052E and
analyze it for a NEC protocol signal.

Ken Shirriff
http://righto.com
""" 
import array
import sys