PCA9555

Dependents:   Telliskivi2_2014 PowerManagementBoard_Rev_A_2017

Files at this revision

API Documentation at this revision

Comitter:
Reiko
Date:
Sun Nov 03 11:43:05 2013 +0000
Parent:
7:3b54389686ca
Commit message:
Added retry on read error

Changed in this revision

PCA9555.cpp Show annotated file Show diff for this revision Revisions of this file
PCA9555.h Show annotated file Show diff for this revision Revisions of this file
diff -r 3b54389686ca -r 8f59b7233e6c PCA9555.cpp
--- a/PCA9555.cpp	Thu Sep 19 07:06:54 2013 +0000
+++ b/PCA9555.cpp	Sun Nov 03 11:43:05 2013 +0000
@@ -1,11 +1,13 @@
 #include "PCA9555.h"
  
 PCA9555::PCA9555(PinName sda, PinName scl, PinName interrupPin, int address)
-        : _irqpin(interrupPin), _i2c(sda, scl) {
+        : _irqpin(interrupPin), _i2c(sda, scl), led3(LED3) {
     _address = address;    
     _irqpin.rise(this, &PCA9555::callChange);
     _irqpin.fall(this, &PCA9555::callChange);
     _i2c.frequency(400000);
+    retryCount = 3;
+    currentRetryCount = retryCount;
 }
 
 void PCA9555::setDirection(int data) {
@@ -19,13 +21,31 @@
 }
  
 int PCA9555::read() {
+    bool isCorrect = false;
     char rx_array[2] = {0x00, 0x00};
     char tx_array[1] = {0x00};
         
-    _i2c.write(_address, tx_array, 1);
-        
-    _i2c.read(_address, rx_array, 2);
-    lastReadState = (rx_array[1] << 8) | rx_array[0];
+    while (--currentRetryCount) {
+        tx_array[0] = 0x00;
+        _i2c.write(_address, tx_array, 1);
+        int success = _i2c.read(_address, rx_array, 2);
+        //_i2c.stop();
+        if (success != 0) {
+            led3 = 1;
+        } else {
+            led3 = 0;
+            currentRetryCount = retryCount;
+            isCorrect = true;
+            break;
+        }
+    }
+    if (isCorrect) {
+        lastReadState = (rx_array[1] << 8) | rx_array[0];
+    }    
+    return lastReadState;
+}
+
+int PCA9555::getLastRead() {
     return lastReadState;
 }
  
diff -r 3b54389686ca -r 8f59b7233e6c PCA9555.h
--- a/PCA9555.h	Thu Sep 19 07:06:54 2013 +0000
+++ b/PCA9555.h	Sun Nov 03 11:43:05 2013 +0000
@@ -23,7 +23,7 @@
      * @return The two bytes read
      */
     int read();
-    
+    int getLastRead();
     /** Write to the IO pins
      * 
      * @param data The 16 bits to write to the IO port
@@ -73,7 +73,9 @@
     int _address;
     unsigned int currentWriteState;
     unsigned int lastReadState;
-    
+    DigitalOut led3;
+    int retryCount;
+    int currentRetryCount;
     void callChange(void);
 };