From 8ef24aa43c181e420b6f06065e304c23f69663a8 Mon Sep 17 00:00:00 2001
From: Owen <owen@easytarget.org>
Date: Wed, 9 Sep 2020 04:30:38 +0200
Subject: [PATCH] Nice little test tool for linear led mapping

---
 linearled/README.md   | 158 +++++++++++++++++++++++++++++++++++++++++-
 linearled/linearled.c |  21 +++++-
 2 files changed, 173 insertions(+), 6 deletions(-)

diff --git a/linearled/README.md b/linearled/README.md
index 3438d1d..f5163a7 100644
--- a/linearled/README.md
+++ b/linearled/README.md
@@ -1,4 +1,156 @@
-## Simple C program used to debut the log function I used for LED control
+## A Simple C program used to debug and examine the log function I used for LED control
+
+The bit width (precision) for the PWM can be specified (max. 16 bit)
+
+The Input values are integer percentages from 0-100.
+
+The Output is a logarithmically scaling integer between 0 and the max PWM value.
+
+``` C
+/* Dump linear led values */
+#include "stdio.h"
+#include <stdlib.h>
+#include <math.h>
+
+//int pwmBits = 9;  // Number of PWM bits
+
+int main(int argc, char **argv) {
+  if (argc != 2) {
+    printf("\nERROR: This utility expects a single parameter; the bit-width of the PWM stream\n\n");
+    return 1; }  
+  
+  int pwmBits = atoi(argv[1]);
+
+  if (pwmBits < 2 || pwmBits > 16) {
+    printf("\nERROR: '%s' is not an integer in the range 2-16.\n\n", argv[1]);
+    return 1; }  
+  
+  int pwmMax = pow(2,pwmBits)-1;
+
+  printf("\nThe PWM Bit width (resolution) specified is %i, pwm range is from 0 to %i\n-----------\n", pwmBits, pwmMax);
+
+  for (int val = 0; val <= 100; val++) {
+    int pwm = round((pow(2,(1+(val*0.02)))-2)/6*pwmMax);
+    printf(" %3i : %5i\n", val, pwm);
+  }
+  printf("\n");
+  return 0;
+}
+```
+
+Adjust the width as necesscary and compile with: 
+
+    $ gcc linearled.c -o linearled -lm
+    
+And run to see the results:
+```bash
+$ ./linearled 9
+
+The PWM Bit width (resolution) specified is 9, pwm range is from 0 to 511
+-----------
+   0 :     0
+   1 :     2
+   2 :     5
+   3 :     7
+   4 :    10
+   5 :    12
+   6 :    15
+   7 :    17
+   8 :    20
+   9 :    23
+  10 :    25
+  11 :    28
+  12 :    31
+  13 :    34
+  14 :    36
+  15 :    39
+  16 :    42
+  17 :    45
+  18 :    48
+  19 :    51
+  20 :    54
+  21 :    58
+  22 :    61
+  23 :    64
+  24 :    67
+  25 :    71
+  26 :    74
+  27 :    77
+  28 :    81
+  29 :    84
+  30 :    88
+  31 :    91
+  32 :    95
+  33 :    99
+  34 :   103
+  35 :   106
+  36 :   110
+  37 :   114
+  38 :   118
+  39 :   122
+  40 :   126
+  41 :   130
+  42 :   135
+  43 :   139
+  44 :   143
+  45 :   148
+  46 :   152
+  47 :   156
+  48 :   161
+  49 :   166
+  50 :   170
+  51 :   175
+  52 :   180
+  53 :   185
+  54 :   190
+  55 :   195
+  56 :   200
+  57 :   205
+  58 :   210
+  59 :   216
+  60 :   221
+  61 :   226
+  62 :   232
+  63 :   238
+  64 :   243
+  65 :   249
+  66 :   255
+  67 :   261
+  68 :   267
+  69 :   273
+  70 :   279
+  71 :   285
+  72 :   292
+  73 :   298
+  74 :   305
+  75 :   311
+  76 :   318
+  77 :   325
+  78 :   332
+  79 :   339
+  80 :   346
+  81 :   353
+  82 :   361
+  83 :   368
+  84 :   375
+  85 :   383
+  86 :   391
+  87 :   399
+  88 :   407
+  89 :   415
+  90 :   423
+  91 :   431
+  92 :   439
+  93 :   448
+  94 :   457
+  95 :   465
+  96 :   474
+  97 :   483
+  98 :   492
+  99 :   502
+ 100 :   511
+```
+
+The code can be adapted into your custom LED setting function
+
 
-Designed to be run on the commandline (unix), Compile with:
-    gcc linearled.c -o linearled -lm
diff --git a/linearled/linearled.c b/linearled/linearled.c
index 9ca6999..98b2e69 100644
--- a/linearled/linearled.c
+++ b/linearled/linearled.c
@@ -1,14 +1,29 @@
 /* Dump linear led values */
 #include "stdio.h"
+#include <stdlib.h>
 #include <math.h>
 
-int pwmBits = 9;  // Number of PWM bits
+//int pwmBits = 9;  // Number of PWM bits
 
-void main() {
+int main(int argc, char **argv) {
+  if (argc != 2) {
+    printf("\nERROR: This utility expects a single parameter; the bit-width of the PWM stream\n\n");
+    return 1; }  
+  
+  int pwmBits = atoi(argv[1]);
+
+  if (pwmBits < 2 || pwmBits > 16) {
+    printf("\nERROR: '%s' is not an integer in the range 2-16.\n\n", argv[1]);
+    return 1; }  
+  
   int pwmMax = pow(2,pwmBits)-1;
 
+  printf("\nThe PWM Bit width (resolution) specified is %i, pwm range is from 0 to %i\n-----------\n", pwmBits, pwmMax);
+
   for (int val = 0; val <= 100; val++) {
     int pwm = round((pow(2,(1+(val*0.02)))-2)/6*pwmMax);
-    printf("%i : %i\n", val, pwm);
+    printf(" %3i : %5i\n", val, pwm);
   }
+  printf("\n");
+  return 0;
 }