How to Add a New CAN Card¶
Introduction¶
The Controller Area Network (CAN) is a network used intensively in many microcontrollers and devices to transfer data between devices without the assistance of a host computer.
The default CAN card used in Apollo is the ESD CAN-PCIe card. You can add a new CAN card using the steps below:
Adding a New CAN Card¶
Complete the following required task sequence to add a new CAN card:
Implement the
CanClient
class of the new CAN card.Register the new CAN card in
CanClientFactory
.Update the config file.
The steps below show how you can add a new CAN card – EXAMPLE CAN card to your stack.
Step 1¶
Let us Implement the CanClient Class of the New CAN Card
Use the following code to implement the specific CANClient
class:
#include <string>
#include <vector>
#include "hermes_can/include/bcan.h"
#include "modules/canbus/can_client/can_client.h"
#include "modules/canbus/common/canbus_consts.h"
#include "modules/common/proto/error_code.pb.h"
/**
* @namespace apollo::canbus::can
* @brief apollo::canbus::can
*/
namespace apollo {
namespace canbus {
namespace can {
/**
* @class ExampleCanClient
* @brief The class which defines an Example CAN client which inherits CanClient.
*/
class ExampleCanClient : public CanClient {
public:
/**
* @brief Initialize the Example CAN client by specified CAN card parameters.
* @param parameter CAN card parameters to initialize the CAN client.
* @return If the initialization is successful.
*/
bool Init(const CANCardParameter& parameter) override;
/**
* @brief Destructor
*/
virtual ~ExampleCanClient() = default;
/**
* @brief Start the Example CAN client.
* @return The status of the start action which is defined by
* apollo::common::ErrorCode.
*/
apollo::common::ErrorCode Start() override;
/**
* @brief Stop the Example CAN client.
*/
void Stop() override;
/**
* @brief Send messages
* @param frames The messages to send.
* @param frame_num The amount of messages to send.
* @return The status of the sending action which is defined by
* apollo::common::ErrorCode.
*/
apollo::common::ErrorCode Send(const std::vector<CanFrame>& frames,
int32_t* const frame_num) override;
/**
* @brief Receive messages
* @param frames The messages to receive.
* @param frame_num The amount of messages to receive.
* @return The status of the receiving action which is defined by
* apollo::common::ErrorCode.
*/
apollo::common::ErrorCode Receive(std::vector<CanFrame>* const frames,
int32_t* const frame_num) override;
/**
* @brief Get the error string.
* @param status The status to get the error string.
*/
std::string GetErrorString(const int32_t status) override;
private:
...
...
};
} // namespace can
} // namespace canbus
} // namespace apollo
Step 2¶
To register the New CAN Card in CanClientFactory,
add the following code to CanClientFactory
:
void CanClientFactory::RegisterCanClients() {
Register(CANCardParameter::ESD_CAN,
[]() -> CanClient* { return new can::EsdCanClient(); });
// register the new CAN card here.
Register(CANCardParameter::EXAMPLE_CAN,
[]() -> CanClient* { return new can::ExampleCanClient(); });
}
Step 3¶
Next, you would need to update the config File
Add the EXAMPLE_CAN into /modules/drivers/canbus/proto/can_card_parameter.proto
message CANCardParameter {
enum CANCardBrand {
FAKE_CAN = 0;
ESD_CAN = 1;
EXAMPLE_CAN = 2; // add new CAN card here.
}
... ...
}
Update /modules/canbus/conf/canbus_conf.pb.txt
... ...
can_card_parameter {
brand:EXAMPLE_CAN
type: PCI_CARD // suppose the new can card is PCI_CARD
channel_id: CHANNEL_ID_ZERO // suppose the new can card has CHANNEL_ID_ZERO
}
... ...
If you use radar, like Conti radar in apollo, its’ canbus configuration file should alse be modified. Update /modules/drivers/radar/conti_radar/conf/conti_radar_conf.pb.txt
... ...
can_card_parameter {
brand:EXAMPLE_CAN
type: PCI_CARD // suppose the new can card is PCI_CARD
channel_id: CHANNEL_ID_ZERO // suppose the new can card has CHANNEL_ID_ZERO
}
... ...