SDO Client#
The CSDO component provides an interface to the CANopen SDO client.
Module Context#
classDiagram
CO_NODE o-- CO_CSDO : Node
CO_FRM o-- CO_CSDO : Frm
CO_CSDO_STATE o-- CO_CSDO : State
CO_CSDO_TRANSFER o-- CO_CSDO : Tfer
class CO_CSDO {
-uint32_t RxId
-uint32_t TxId
-uint8_t NodeId
+COCSdoFind(num)
+COCSdoRequestUpload(key, buffer, size, callback, timeout)
+COCSdoRequestDownload(key, buffer, size, callback, timeout)
}
class CO_CSDO_STATE {
<<enumeration>>
}
Structure Data#
The class CO_CSDO
is defined within co_csdo.h
and is responsible for the CANopen SDO client handling. The following data members are in this class:
Data Member | Type | Description |
---|---|---|
TxId | uint32_t |
COB-ID for the transmitted SDO request |
RxId | uint32_t |
COB-ID for the received SDO response |
NodeId | uint8_t |
Node-Id of addressed SDO server |
Info
The data within this structure must never be manipulated without the corresponding class member functions. This can lead to unpredictable behavior of the node.
Member Functions#
The following chapters describes the API functions of the CANopen SDO client module. These functions are implemented within the source file: co_csdo.c/h
COCSdoFind()#
The function checks the availability of the given SDO client index and returns the corresponding CO_CSDO object.
Prototype
CO_CSDO *COCSdoFind(CO_NODE *node, uint8_t num);
Arguments
Parameter | Description |
---|---|
node | Pointer to parent CANopen node |
num | SDO client number (1..127) |
Returned Value
- The function returns a valid
CO_CSDO
object when addressed SDO client is ready for initiating a new transfer. Otherwise, an invalidCO_CSDO
object is returned.
Example
The following example checks the state of SDO client #2.
CO_CSDO *csdo;
:
csdo = COCSdoFind(&(AppNode), 2);
if (csdo == 0) {
/* SDO client #2 is missing or busy */
} else {
/* SDO client #2 is usable */
}
:
COCSdoRequestDownload()#
The function starts an SDO download transfer in the calling node to write data to the configured SDO server node-id. When the size of data transfer is lower or equal 4 an expedited transfer is used, otherwise a segmented transfer is initiated.
Prototype
CO_ERR COCSdoRequestDownload(CO_CSDO *csdo,
uint32_t key,
uint8_t *buffer,
uint32_t size,
CO_CSDO_CALLBACK_T callback,
uint32_t timeout);
Arguments
Parameter | Description |
---|---|
csdo | Pointer to SDO client object |
key | destination object entry on SDO server Node-Id |
buffer | pointer to buffer with data |
size | size in byte of data within the buffer |
callback | user provided callback for transfer finalization |
timeout | transfer timeout in milliseconds |
Returned Value
- The function returns
CO_ERR_NONE
when transfer is initiated successfully. Any other error code indicates, that the transfer is not started.
Example
The following example writes a 32bit value to the remote node object dictionary entry [1234h:02
] with SDO client #1 and a transfer timeout of 1s.
uint32_t writeValue = 0;
/* The application specific SDO transfer finalization callback */
void AppCSdoFinishCb(CO_CSDO *csdo, uint16_t index, uint8_t sub, uint32_t code)
{
if (code == 0) {
/* data written successfully in remote node */
} else {
/* a timeout or abort is detected during SDO transfer */
}
}
/* somewhere in your application: */
void foo()
{
CO_CSDO *csdo;
CO_ERR err;
:
csdo = COCSdoFind(&(AppNode), 1);
writeValue = 42;
err = COCSdoRequestDownload(csdo, CO_DEV(1234,02),
&writeValue, sizeof(writeValue),
AppCSdoFinishCb, 1000);
if (err == CO_ERR_NONE) {
/* Transfer is started successfully */
/* Note: don't change the 'writeValue' until transfer is finished! */
} else {
/* Unable to start the SDO transfer */
}
:
}
COCSdoRequestUpload()#
The function starts an SDO upload transfer in the calling node to read data from the configured SDO server node-id. When the size of data transfer is lower or equal 4 an expedited transfer is used, otherwise a segmented transfer is initiated.
Prototype
CO_ERR COCSdoRequestUpload(CO_CSDO *csdo,
uint32_t key,
uint8_t *buffer,
uint32_t size,
CO_CSDO_CALLBACK_T callback,
uint32_t timeout);
Arguments
Parameter | Description |
---|---|
csdo | Pointer to SDO client object |
key | destination object entry on SDO server Node-Id |
buffer | pointer to buffer with data |
size | size in byte of data within the buffer |
callback | user provided callback for transfer finalization |
timeout | transfer timeout in milliseconds |
Returned Value
- The function returns
CO_ERR_NONE
when transfer is initiated successfully. Any other error code indicates, that the transfer is not started.
Example
The following example reads a 32 bytes from the remote node object dictionary entry [1234h:02
] with SDO client #1 and a transfer timeout of 1s.
uint8_t readValue[32] = { 0 };
/* The application specific SDO transfer finalization callback */
void AppCSdoFinishCb(CO_CSDO *csdo, uint16_t index, uint8_t sub, uint32_t code)
{
if (code == 0) {
/* read data is available in 'readValue' */
} else {
/* a timeout or abort is detected during SDO transfer */
}
}
/* somewhere in your application: */
void foo()
{
CO_CSDO *csdo;
CO_ERR err;
:
csdo = COCSdoFind(&(AppNode), 1);
err = COCSdoRequestUpload(csdo, CO_DEV(1234,02),
&readValue, 32,
AppCSdoFinishCb, 1000);
if (err == CO_ERR_NONE) {
/* Transfer is started successfully */
/* Note: don't use the 'readValue' until transfer is finished! */
} else {
/* Unable to start the SDO transfer */
}
:
}