CANSEND

CANSEND

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Action

Puts the Message Object into Transmit mode and send out data.

 

 

Syntax

status = CANSEND(object, var[,bytes])

 

 

Remarks

status

The status of sending the frame. This should be 0 if there was no problem. If there is an error it will return 1 or higher. The return value is the CANSTMOB register content with the TX bit cleared.

object

The message object number in the range from 0-14.

The MOB must have been configured into the DISABLED mode before CANSEND can be used.

var

A variable or array which content will be send. The data type of the variable will be used to determine the number of bytes to send.

bytes

This is an optional value. You can specify how many bytes must be transmitted.

 

The CANSEND function will disable the TX interrupt and then polls the CANSTMOB register for a change of flags. The TX flag is cleared so that a successful transmission returns a 0.

In case of ACK errors or other errors, a value other then 0 will be returned. Right after the status has changed, the TX and Error interrupt are enabled again and the CAN interrupt routine is executed. You need to reconfigure the MOB in all cases otherwise you can not send new data.

 

 

 

See also

CONFIG CANBUS , CONFIG CANMOB , CANBAUD, CANRESET, CANCLEARMOB, CANCLEARALLMOBS, CANRECEIVE , CANID, CANSELPAGE, CANGETINTS

 

 

 

 

Example

Have a look at CONFIG CANBUS for a full example.

The code below only demonstrates that you MUST configure the MOB again in the interrupt routine.

The code below is taken from the sample you find under CONFIG CANBUS

 

Elseif Canstmob.6 = 1 Then                         'transmission ready
  Config Canmob = -1 , Bitlen = 11 , Msgobject = Disabled , Msglen = 1 , Clearmob = No
  ' reconfig with value -1 for the current MOB and do not set ID and MASK

Elseif Canstmob.0 = 1 Then                         'ACK ERROR
  Config Canmob = -1 , Bitlen = 11 , Msgobject = Disabled , Msglen = 1 , Clearmob = No
  ' reconfig with value -1 for the current MOB and do not set ID and MASK