COObjRdValue()

This function reads the value of the given object entry.

Description

The access with this function to an object entry will be done with casting of the object entry values to the requested value width.

Prototype

int16_t COObjRdValue(CO_OBJ  *obj ,
                     void    *value,
                     uint8_t  width,
                     uint8_t  nodeid);

Arguments

Parameter Description
obj pointer to object entry
value pointer to destination memory
width width of read value (must be 1, 2 or 4 and reflecting the width of the referenced variable, given by parameter value)
nodeid device node ID (only relevant in case of node ID dependent value)

Returned Value

  • ==CO_ERR_NONE : successful operation
  • !=CO_ERR_NONE : an error is detected (see CONodeGetErr())

Example

The following example gets the value of the hypothetical application specific object entry “[1234:56]” within the object dictionary of the CANopen node AppNode.

    uint32_t  value;
    CO_OBJ   *entry;
    :
    entry = CODirFind     (&(AppNode.Dir), CO_DEV(0x1234,0x56));
    err   = COObjRdValue  (entry, &value, 4, 0);
    :

Note: The example shows a read access with the knowledge, that the addressed object entry is independent from the node ID. To be independent from this knowledge, the API function CONmtGetNodeId() may be used to get the current node ID.