Diff: IQS62x.cpp

Revision:

12:5a9bbbd6e312

Parent:

11:4d6d1da5bd31

Child:

13:71f8ee16a3a1

--- a/IQS62x.cpp	Fri May 12 14:55:20 2017 +0000
+++ b/IQS62x.cpp	Fri May 12 23:14:44 2017 +0000
@@ -9,23 +9,33 @@
 #include "IQS62x.h"
 
 // constructor
-IQS62xIO::IQS62xIO() : 
+IQS62xIO::IQS62xIO() :
     i2c( IQS_I2C_DATA_PIN, IQS_I2C_CLOCK_PIN ), // first run the constructor for mbed class I2C
     IQSready( IQS_READY_PIN )                   // first run the constructor for mbed class DigitalIn
-{    
+{
     registers = I2CBuffer; // pointer to the receive buffer
     I2CErrorCount = 0; // reset I2C error count
     i2c.frequency( I2Cspeed ); // I2C clock frequency
-}    
+
+    // this uses memory but is very handy in diagnostics
+    memset(writeFlag,    0, I2CBufferSize); // a table to remmber if we wrote to a register
+    memset(lastWrite,    0, I2CBufferSize); // a table to remember what we wrote to a register
+    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(writeChanges, 0, I2CBufferSize); // a table to mark up any registers that differs from what was written to it
+}
 
 // write a single byte to an IQS62x register
-void IQS62xIO::writeRegister(int address, int data) {
+void IQS62xIO::writeRegister(int address, int data)
+{
+    writeFlag[ address & 0xff ] = 1; // remember which registers we changed
+    lastWrite[ address & 0xff ] = data & 0xff; // remember what we wrote
     char twoBytes [2];
     int numberOfBytes = 2;
     twoBytes[0] = address & 0xff;
     twoBytes[1] = data & 0xff;
-    waitForReady();
-    if(0!=i2c.write(I2C_ADR,twoBytes,numberOfBytes,false)) 
+    waitForIqsReady();
+    if(0!=i2c.write(I2C_ADR,twoBytes,numberOfBytes,false))
         I2CErrorCount++;
 }
 
@@ -33,34 +43,56 @@
 #include "deviceType.h" // to check if we should override the configuration definition
 #ifndef OVERRIDE_CONFIGURE
 // if there is no override for configure() then we use this simple version
-void IQS62xIO::configure() {
+void IQS62xIO::configure()
+{
     writeRegister(0xd0,0x40); // simplest config : just acknowledge/clear the reset flag
 }
 #endif
 
 // read N registers, starting at provided offset
-void IQS62xIO::readIqsRegisters(int start, int count){
+void IQS62xIO::readIqsRegisters(int start, int count)
+{
     memset(I2CBuffer,0x55,I2CBufferSize); // "clear" i2c receive buffer
-    waitForReady();
-    char i2c_start_address [1]; 
+    waitForIqsReady();
+    char i2c_start_address [1];
     i2c_start_address[0] = start & 0xff;
     int numberOfBytes = 1;
     // write start address to the IQS62x address register
-    if(0!=i2c.write(I2C_ADR,i2c_start_address,numberOfBytes,false)) 
+    if(0!=i2c.write(I2C_ADR,i2c_start_address,numberOfBytes,false))
         I2CErrorCount++;
-    waitForReady();
+    waitForIqsReady();
     numberOfBytes = count % I2CBufferSize;
     // read register values into a buffer
     if(0!=i2c.read(I2C_ADR,I2CBuffer,numberOfBytes,false))
         I2CErrorCount++;
+
+#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
+    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] ) 
+            writeChanges[i]=1; // if register different from what we wrote, mark it
+        }
+        if ( I2CBuffer[i] != lastRead[i] )
+            readChanges[i]=1; // if register differs from previous read, mark it
+        else
+            readChanges[i]=0; // no change, no flag
+    }
+    memcpy(lastRead, I2CBuffer, I2CBufferSize); // preserve data for next round
+#endif
 }
 
 // wait for IQS62x to provide a ready signal (low) on IQS62x_ready pin
-void IQS62xIO::waitForReady() {
-    int timeout=0; 
+void IQS62xIO::waitForIqsReady()
+{
+    int timeout=0;
     while (1) {
         if(IQSready==1) break;
-        if (timeout++ > 1000000) goto fatal_error; 
+        if (timeout++ > 1000000) goto fatal_error;
     }
     timeout=0;
     while (1) {
@@ -68,6 +100,6 @@
         if (timeout++ > 1000000) goto fatal_error;
     }
     return;
-    fatal_error:
-        error ("Fatal Error: IQS62x ready pin is not toggling");
+fatal_error:
+    error ("Fatal Error: IQS62x ready pin is not toggling");
 }
\ No newline at end of file