init_FiltRang() – di-ce.de

Description

init_FiltRang( num, ext, id_low, id_high) – configures the CAN-filter number num to receive messages in the given range (standard or extended ID messages).

Syntax

MCAN0.init_FiltRang( num, ext, id_low, id_high)

Parameters

uint8_t num– filter number – Standard 11bit: FILTER_0, FILTER_1 . . . FILTER_7) or
– Extended 29bit: FILTER_EXT_0, FILTER_EXT_1 . . . FILTER_EXT_7)
uint8_t ext – extended ID – 0 for a Standard 11bit ID filter definition
– 1 for an Extended 29 bit ID filter definition
uint32_t id_low – message ID – 11 / 29bit identifier defining the start of the ID range (id_low included)
uint32_t id_high – message ID – 11 / 29bit identifier defining the end of the ID range (id_high included)

Returns

uint8_t:
CAN_OK – OK. Filter successfully configured.
CAN_FAILINIT – Error. Filter could not be configured. Check if id_low < id_high and filter num in the range above.

Example Code

The following example receives messages on the CAN bus (MCAN0).

void setup()
{
  while(!Serial);
  Serial.println("Example filtering CAN messages");
  // Add a Range filter of extended IDs
  MCAN0.init_FiltRang(FILTER_EXT_0, 1 , 0x7000, 0x8000);
  // Disable the pre-configured FILTER_0 to not receive all std. msg. anymore
  MCAN0.disableFilter(FILTER_0, 0);
}

void loop()
{
  if( MCAN0.checkReceive() )
  {
    CANMessage t_canMesgToRecv;    
    if(MCAN0.readMsgBuf( t_canMesgToRecv ) == CAN_OK)
      Serial.println(t_canMesgToRecv.toString());
  }
}

Notes and Warnings

At start-up, the filters FILTER_0 and FILTER_EXT_0 are pre-configured to receive all standard (FILTER_0) and all extended IDs (FILTER_EXT_0). Please, consider that if you edit one filter that the other one might still active.
Always use the given defines FILTER_x/ FILTER_EXT_x for the parameter num.
When configuring a filter for standard IDs use num: FILTER_x and set ext:0, if a filter for extended identifiers should be configured, then use num: FILTER_EXT_x and set ext:1.

Allowing all messages:

In order to let all messages be accepted again, just set two filters as follows. One (e.g. FILTER_0) for all standard IDs and another one for all extended IDs (e.g. FILTER_EXT_0):

init_FiltID(FILTER_0,     0, 0, MSG_ID_ALLOW_ALL_MASK);
init_FiltID(FILTER_EXT_0, 1, 0, MSG_ID_ALLOW_ALL_MASK);

Examples can be found in the Arduino IDE menu:
File -> Examples -> DICE -> CAN Bus ->