Diff: IQS62x.cpp

Revision:

19:f0675a3150c7

Parent:

18:b85048ec91d2

Child:

20:7eb08a52b954

diff -r b85048ec91d2 -r f0675a3150c7 IQS62x.cpp
--- a/IQS62x.cpp	Tue May 16 14:23:28 2017 +0000
+++ b/IQS62x.cpp	Thu May 18 15:23:40 2017 +0000
@@ -24,7 +24,7 @@
     memset(lastRead,         0, I2CBufferSize); // a table to remmber what we read the previous read cycle
     memset(readChanges,      0, I2CBufferSize); // a table to mark up any registers that changed since the previous read
     memset(readChangesEver,  0, I2CBufferSize); // a table to mark up any registers that changed BUT never forget
-    memset(writeChanges,     0, I2CBufferSize); // a table to mark up any registers that differs from what was written to it
+    memset(writeChanges,     0, I2CBufferSize); // a table to mark up any registers that differ from what was written to it
 }
 
 // write a single byte to an IQS62x register
@@ -72,11 +72,15 @@
 #define PLEASE_CHECK_FOR_IQS_CHANGES 1
 #ifndef DONT_CHECK_FOR_IQS_CHANGES
     // this is optional but handy diagnostics
-    // we build two tables:
-    // writeChanges[i] is set to 1 if the register content differs from what we wrote to it
-    // readChanges[i] is set to 1 if the register value differs from the previously read value
+    // we build six tables:
+    //writeFlag -       a table to remmber if we wrote to a register
+    //lastWrite -       a table to remember what we wrote to a register
+    //lastRead -        a table to remmber what we read the previous read cycle
+    //readChanges -     a table to mark up any registers that changed since the previous read
+    //readChangesEver - a table to mark up any registers that changed BUT never forget
+    //writeChanges -    a table to mark up any registers that differ from what was written to it
+    if (IQSframes == 1) memcpy(lastRead, I2CBuffer,I2CBufferSize); // if this is the first frame init the history buffer
     if (IQSframes < 20) memset(readChangesEver,0,I2CBufferSize); // clear this until we have had 20 full reads
-    if (IQSframes == 1) memcpy(lastRead, I2CBuffer,I2CBufferSize); // if this is the first frame init the history buffer
     for(int i=0; i<I2CBufferSize; i++) {
         if (writeFlag[i] == 1) { // only if we previously wrote to this register we check it
             if( I2CBuffer[i] != lastWrite[i] ) 
@@ -89,7 +93,7 @@
             if (readChanges[i] > 0) readChanges[i]--; // bring it closer to zero
         }
     }
-    memcpy(lastRead, I2CBuffer, I2CBufferSize); // preserve data for next round
+    memcpy(lastRead, I2CBuffer, I2CBufferSize); // preserve history for next round
 #endif
 }