tidying up ADC api

3 files changed, 33 insertions, 24 deletions

diff --git a/include/app.h b/include/app.h
index 83ef48a..96801eb 100644
--- a/include/app.h
+++ b/include/app.h
@@ -133,6 +133,11 @@ void hal_write_flash(u32 offset,const u8 *data, u32 length);
 
 /**
  * Called on startup, this is a good place to do any initialisation.
+ *
+ * @param adc_buffer -  this is a pointer to the raw ADC frame buffer. The
+ *                                              data is 12 bit unsigned. Note the indexing is strange - 
+ *                                              translate ADC indices to LED/button indices using the
+ *                                              ADC_MAP table declared in app_defs.h.
  */
 void app_init(const u16 *adc_buffer);
 
diff --git a/include/app_defs.h b/include/app_defs.h
index 7a3efa1..d9b4311 100644
--- a/include/app_defs.h
+++ b/include/app_defs.h
@@ -107,5 +107,26 @@ typedef unsigned char  u8;
 #define USER_AREA_SIZE 1024
 
 // ____________________________________________________________________________
+//
+// Raw ADC reads. For technical reasons, the ADC layout is not the same as the
+// LED layout. Be sure to translate ADC values using the table below as you
+// need them!
+// ____________________________________________________________________________
+
+#define PAD_COUNT 64
+
+static const u8 ADC_MAP[PAD_COUNT] =
+{
+        11, 51, 12, 52, 13, 53, 14, 54,
+        15, 55, 16, 56, 17 ,57, 18, 58,
+        21, 61, 22, 62, 23, 63, 24, 64,
+        25, 65, 26, 66, 27, 67, 28, 68,
+        31, 71, 32, 72, 33, 73, 34, 74,
+        35, 75, 36, 76, 37, 77, 38, 78,
+        41, 81, 42, 82, 43, 83, 44, 84,
+        45, 85, 46, 86, 47, 87, 48, 88,
+};
+
+// ____________________________________________________________________________
 
 #endif
diff --git a/src/app.c b/src/app.c
index 3499d58..d4db1f9 100644
--- a/src/app.c
+++ b/src/app.c
@@ -45,8 +45,6 @@
 // In this example, we render the raw ADC data as LED rainbows.
 //______________________________________________________________________________
 
-#define PAD_COUNT 64
-
 static const u16 *g_ADC = 0;
 
 //______________________________________________________________________________
@@ -82,33 +80,18 @@ void app_cable_event(u8 type, u8 value)
 
 //______________________________________________________________________________
 
-static const u8 ADC_MAP[PAD_COUNT] =
-{
-        11, 51, 12, 52, 13, 53, 14, 54,
-        15, 55, 16, 56, 17 ,57, 18, 58,
-        21, 61, 22, 62, 23, 63, 24, 64,
-        25, 65, 26, 66, 27, 67, 28, 68,
-        31, 71, 32, 72, 33, 73, 34, 74,
-        35, 75, 36, 76, 37, 77, 38, 78,
-        41, 81, 42, 82, 43, 83, 44, 84,
-        45, 85, 46, 86, 47, 87, 48, 88,
-};
-
-
 void app_timer_event()
 {
-        // example: render raw ADC data as LEDs
+        // render raw ADC data as LEDs
         for (int i=0; i < PAD_COUNT; ++i)
         {
                 // raw adc values are 12 bit, but LEDs are 6 bit.
-                // so saturate into r;g;b for a rainbow effect to show pressure
-                u16 r =0;
-                u16 g =0;
-                u16 b =0;
-                
-                u16 x = g_ADC[i];
+                // Let's saturate into r;g;b for a rainbow effect to show pressure
+                u16 r = 0;
+                u16 g = 0;
+                u16 b = 0;
                 
-                x = (3 * MAXLED * x) >> 12;
+                u16 x = (3 * MAXLED * g_ADC[i]) >> 12;
                 
                 if (x < MAXLED)
                 {
@@ -134,6 +117,6 @@ void app_timer_event()
 void app_init(const u16 *adc_raw)
 {
         
-        // example - store off the raw ADC frame pointer for later use
+        // store off the raw ADC frame pointer for later use
         g_ADC = adc_raw;
 }