Revision 6:d2452e9b169b, committed 2015-10-05

Comitter:

Bobty

Date:

Mon Oct 05 14:03:29 2015 +0000

Parent:

5:45b6a39002f1

Child:

7:0a87f8c2d9e6

Commit message:

Changed return code from search to be more meaningful about the reason for failure

Changed in this revision

--- a/Onewire.cpp	Mon Sep 28 10:31:58 2015 +0000
+++ b/Onewire.cpp	Mon Oct 05 14:03:29 2015 +0000
@@ -128,7 +128,12 @@
 
 // Search Copied from Arduino code
 //
-// Perform a search. If this function returns a '1' then it has
+// Perform a search.
+// Returns 
+// ONEWIRE_OK if a new address has been returned.
+// ONEWIRE_SEARCH_ALL_DONE = all devices found
+// ONEWIRE_SEARCH_INIT_FAIL = failed to init
+// ONEWIRE_SEARCH_NOT_FOUND = no devices found If this function returns a '1' then it has
 // enumerated the next device and you may retrieve the ROM from the
 // Onewire::address variable. If there are no devices, no further
 // devices, or something horrible happens in the middle of the
@@ -146,7 +151,8 @@
 uint8_t Onewire::search(uint8_t *newAddr)
 {
    uint8_t id_bit_number = 1;
-   uint8_t last_zero = 0, rom_byte_number = 0, search_result = 0;
+   uint8_t last_zero = 0, rom_byte_number = 0;
+   uint8_t search_result = ONEWIRE_SEARCH_ALL_DONE;
    uint8_t id_bit = 0, cmp_id_bit = 0;
 
    // initialize for search
@@ -162,7 +168,7 @@
          _search_LastDiscrepancy = 0;
          _search_LastDeviceFlag = false;
          _search_LastFamilyDiscrepancy = 0;
-         return false;
+         return ONEWIRE_SEARCH_INIT_FAIL;
       }
 
       // issue the search command
@@ -239,18 +245,20 @@
          if (_search_LastDiscrepancy == 0)
             _search_LastDeviceFlag = true;
 
-         search_result = true;
+         search_result = ONEWIRE_OK;
       }
    }
 
    // if no device found then reset counters so next 'search' will be like a first
-   if (!search_result || !_search_ROM_NO[0])
+   if (!_search_ROM_NO[0])
    {
       _search_LastDiscrepancy = 0;
       _search_LastDeviceFlag = false;
       _search_LastFamilyDiscrepancy = 0;
-      search_result = false;
+      search_result = ONEWIRE_SEARCH_NOT_FOUND;
    }
+   if (search_result != ONEWIRE_OK)
+        return search_result;
    for (int i = 0; i < ONEWIRE_ADDR_BYTES; i++)
        newAddr[i] = _search_ROM_NO[i];
    return search_result;

--- a/Onewire.h	Mon Sep 28 10:31:58 2015 +0000
+++ b/Onewire.h	Mon Oct 05 14:03:29 2015 +0000
@@ -5,9 +5,15 @@
 
 #define ONEWIRE_ADDR_BYTES 8
 
-class Onewire{
+const int ONEWIRE_OK = 0;
+const int ONEWIRE_SEARCH_ALL_DONE = 1;
+const int ONEWIRE_SEARCH_INIT_FAIL = 2;
+const int ONEWIRE_SEARCH_NOT_FOUND = 3;
 
-public:
+class Onewire
+{
+
+public:    
     Onewire(PinName oneBus);
     void writeBit(int bit);
     int readBit();
@@ -18,10 +24,13 @@
 
     // Clear the search state so that if will start from the beginning again.
     void reset_search();
-    // Look for the next device. Returns 1 if a new address has been
-    // returned. A zero might mean that the bus is shorted, there are
-    // no devices, or you have already retrieved all of them.  It
-    // might be a good idea to check the CRC to make sure you didn't
+    // Look for the next device.
+    // Returns 
+    // ONEWIRE_OK if a new address has been returned.
+    // ONEWIRE_SEARCH_ALL_DONE = all devices found
+    // ONEWIRE_SEARCH_INIT_FAIL = failed to init
+    // ONEWIRE_SEARCH_NOT_FOUND = no devices found
+    // It might be a good idea to check the CRC to make sure you didn't
     // get garbage.  The order is deterministic. You will always get
     // the same devices in the same order.
     uint8_t search(uint8_t *newAddr);