Add support for listen only mode

FlexCAN.cpp

@@ -115,6 +115,17 @@ void FlexCAN::setFilter(const CAN_filter_t &filter, uint8_t n)
   }
 }
 
+// -------------------------------------------------------------
+void FlexCAN::enableListenOnlyMode(void)
+{
+  FLEXCAN0_CTRL1 |= FLEXCAN_CTRL_LOM;
+}
+
+// -------------------------------------------------------------
+void FlexCAN::disableListenOnlyMode(void)
+{
+  FLEXCAN0_CTRL1 &= ~FLEXCAN_CTRL_LOM;
+}
 
 // -------------------------------------------------------------
 int FlexCAN::available(void)
@@ -223,4 +234,3 @@ int FlexCAN::write(const CAN_message_t &msg)
 
   return 1;
 }
-

FlexCAN.h

@@ -35,6 +35,8 @@ class FlexCAN
     begin(defaultMask);
   }
   void setFilter(const CAN_filter_t &filter, uint8_t n);
+  void enableListenOnlyMode(void);
+  void disableListenOnlyMode(void);
   void end(void);
   int available(void);
   int write(const CAN_message_t &msg);

README.md

@@ -46,6 +46,15 @@ Enable the CAN to start actively participating on the CANbus.  Enable reception
 **setFilter(filter, number)**
 Set the receive filter selected by number, 0-7.  When using filters it is required to set them all. If the application uses less than 8 filters, duplicate one filter for the unused ones.
 
+**enableListenOnlyMode()**
+Enable the listen only mode. Can only be set before calling begin() or after end().
+In this mode, transmission is disabled, all error counters are frozen and the module
+operates in a CAN Error Passive mode. Only messages acknowledged by another
+CAN station will be received.
+
+**disableListenOnlyMode()**
+Disable the listen only mode. Can only be set before calling begin() or after end().
+
 The mask and filter are **CAN_filter_t** type structures.
 
 ###Caller Blocking Support
@@ -59,4 +68,3 @@ The timeout monitoring mechanism calls **yield()** until a buffer is found or th
 
 ###In-order Transmission
 Caller blocking can be used to **write()** frames guaranteed in-order to the bus. When caller blocking is selected for **write()** (non-zero timeout specified), a single hardware transmit buffer is used.
-

keywords.txt

@@ -2,11 +2,12 @@ FlexCAN	KEYWORD1
 
 begin	KEYWORD2
 setFilter	KEYWORD2
+enableListenOnlyMode KEYWORD2
+disableListenOnlyMode KEYWORD2
 end	KEYWORD2
 read	KEYWORD2
 write	KEYWORD2
 available	KEYWORD2
 
 CAN_message_t	KEYWORD1
 CAN_filter_t	KEYWORD1
-