CanReceive

Function

Get CAN and CAN FD reception message.

Format

Ret = CanReceive ( Id , ChannelNo , MessageNum , MessageType , CanId , DataLength , Data , ErrorCode , TickCount )

Parameters

Id [ C: short ] [ Python: ctypes.c_short ]
Specify the device ID retrieved from CanInit.

ChannelNo [ C: unsigned short ] [ Python: ctypes.c_ushort ]
Specify the channel number.

MessageNum [ C:unsigned int *] [ Python: ctypes.POINTER(ctypes.c_uint) ]
Specify the address that stores the number of valid received messages.
Specify the memory address that stores the prepared number of received messages (number of arrays) and call the function.

Store received messages within the range of number of received messages (array number) inside the function.
Additionally, MessageNum is overwritten with the valid number of received messages, and the function returns.

The storage range is 1 to 170.

MessageType [ C:unsigned int *] [ Python: ctypes.POINTER(ctypes.c_uint) ]
Specify the start address of the one-dimensional array that stores the received message type.
If multiple message types are valid, the function processing returns with bitwise operations performed using logical OR.

Definition

Value
[Hex]

Description

CCAN_MSG_TYPE_CAN

0x01

CAN message

CCAN_MSG_TYPE_CAN_FD

0x02

CAN FD message

CCAN_MSG_TYPE_REMOTE_FRAME

0x04

Remote frame

CCAN_MSG_TYPE_BITRATE_SWITCH

0x08

Bitrate switch

CCAN_MSG_TYPE_EXTENDED_FORMAT

0X20

Extended format

CanId [ C:unsigned int *] [ Python: ctypes.POINTER(ctypes.c_uint) ]
Specify the start address of the one-dimensional array that stores the received CAN ID.

If standard format is specified, it is specified by base ID (11bit).
Valid specification range is 0x000 to 0x7FF.

If extended format is specified, it is specified as extended ID + base ID (29 bits in total).
Valid specification range is 0x000 to 0x1FFFFFFF.

CanId bit number

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

09

08

07

06

05

04

03

02

01

00

Extended ID/Base ID

-

-

-

Extended ID

Base ID

Bit number of each ID

-

-

-

17

16

15

14

13

12

11

10

09

08

07

06

05

04

03

02

01

00

10

09

08

07

06

05

04

03

02

01

00

DataLength  [ C:unsigned short *] [ Python: ctypes.POINTER(ctypes.c_ushort) ]
Specify the start address of the one-dimensional array that stores the received message data length.

If CAN communication is specified, valid specification ranges are 0 to 8.
If CAN FD communication is specified, valid specification ranges are 0 to 8, and 12, 16, 20, 24, 32, 48, 64.

Data [ C:unsigned char *] [ Python: ctypes.POINTER(ctypes.c_ubyte) ]
Specify the start address of the two-dimensional array that will store the received data.
The number of elements (number of columns) of the two-dimensional array is 64.

ErrorCode  [ C:unsigned int *] [ Python: ctypes.POINTER(ctypes.c_uint) ]
Specify the start address of a one-dimensional array that stores errors that occur when receiving each message in CAN communication.

Definition

Value
[Dec]

Description

CCAN_STATUS_ERR_SUCCESS

0

Success

CCAN_STATUS_ERR_BIT

1

Bit error
Since this is an error frame, parameters other than TickCount will be invalid data.

CCAN_STATUS_ERR_FORM

2

Form error
Since this is an error frame, parameters other than TickCount will be invalid data.

CCAN_STATUS_ERR_STUFF

3

Stuff error
Since this is an error frame, parameters other than TickCount will be invalid data.

CCAN_STATUS_ERR_ACK

4

ACK error
Since this is an error frame, parameters other than TickCount will be invalid data.

CCAN_STATUS_ERR_CRC

5

CRC error
Since this is an error frame, parameters other than TickCount will be invalid data.

CCAN_STATUS_ERR_OTHER

6

Other error
Since this is an error frame, parameters other than TickCount will be invalid data.

TickCount [ C:unsigned long long *] [ Python: ctypes.POINTER(ctypes.c_ulonglong) ]
Specify the start address of the one-dimensional array that stores the tick count value when receiving.
The unit is nsec.

Return Value

Ret [ C: long ] [ Python: ctypes.c_long ]

Definition

Value
[Dec]

Description

CAN_ERR_SUCCESS

0

Normality completion

CAN_ERR_SYS_RECOVERED_FROM_STANDBY

7

Execute CanResetDevice function because the device has recovered from standby mode.

CAN_ERR_DLL_INVALID_ID

10001

Invalid ID specified.

CAN_ERR_DLL_CALL_DRIVER

10002

Driver can't be called (Failed in the ioctl).

CAN_ERR_DLL_BUFF_ADDRESS

10100

Invalid data buffer address.

CAN_ERR_SYS_CH_NO

20101

Channel number is outside the settable range

CAN_ERR_SYS_MESSAGE_NUM

20150

The number of messages is outside the settable range.

CAN_ERR_SYS_REC_FIFO_OVERFLOW

20220

Receive FIFO overflowed.

CAN_ERR_SYS_BUSOFF

20201

Cannot execute because the bus is off.

CAN_ERR_SYS_BUS_DISCONNECT

20202

Cannot execute because the bus is disconnected.

The others (See also: Details of Error Code)

Initial Value

None

Remarks

Get CAN and CAN FD reception message.

Please verify that ErrorCode argument is CCAN_STATUS_ERR_SUCCESS before checking each reception message even though the return value is normal.
Otherwise, the data returned by the other arguments will be invalid.

For message type (MessageType), CAN ID (CanId), data length (DataLength), error code (ErrorCode) and tick count (TickCount), allocate memory in a one-dimensional array, and take the start addresses as arguments.
By specifying the message number as the index of the one-dimensional array, you can refer to the value for the target message number.

Image of one-dimensional array:

Array variable name[message number]

Element value (example)

MessageType[0]

CCAN_MSG_TYPE_CAN

MessageType[1]

CCAN_MSG_TYPE_CAN

MessageType[2]

CCAN_MSG_TYPE_CAN

MessageType[3]

CCAN_MSG_TYPE_CAN

...

...

MessageType[MessageNum - 1]

CCAN_MSG_TYPE_CAN

 

Memory is allocated for the received data (Data) as a two-dimensional array with 64 elements, and the start address is taken as an argument.
By specifying the message number as the first index of the two-dimensional array, you can refer to the received data for each message number.
By specifying the element number in the second index of the two-dimensional array, you can refer to the individual element value.


Image of two-dimensional array:

Array variable name[message number][(element number)]

Value of element 01

Value of element 02

Value of element 03

...

Value of element 64

Data[0][]

Data[0][0]

Data[0][1]

Data[0][2]

...

Data[0][63]

Data[1][]

Data[1][0]

Data[1][1]

Data[1][2]

...

Data[1][63]

Data[2][]

Data[2][0]

Data[2][1]

Data[2][2]

...

Data[2][63]

Data[3][]

Data[3][0]

Data[3][1]

Data[3][2]

...

Data[3][63]

...

...

...

...

...

...

Data[MessageNum - 1][]

Data[MessageNum - 1][0]

Data[MessageNum - 1][1]

Data[MessageNum - 1][2]

...

Data[MessageNum - 1][63]

 

Example

Get CAN reception message from ChannelNo = 1. MessageNum =1, MessageType = CCAN_MSG_TYPE_CAN, CAN ID = 0x11c, DataLength = 1, Data = 0xff

C

long Ret;

unsigned int MessageNum;

unsigned int MessageType[1];

unsigned int CanId[1];

unsigned short DataLength[1];

unsigned char Data[1][64];
unsigned int ErrorCode[1];

unsigned long long TickCount[1];

MessageNum = 1;

 


Ret = CanReceive ( Id , 1 , &MessageNum , &MessageType[0] , &CanId[0] , &Data[0][0] , &ErrorCode[0] , &TickCount[0] );
 

Python

Ret = ctypes.c_long()

MessageNum = ctypes.c_uint()

MessageTypeType = ctypes.c_uint() * 1

MessageType = MessageTypeType()

CanIdType = ctypes.c_uint() * 1

CanId = CanIdType()

DataLengthType = ctypes.c_ushort() *1

DataLength = DataLengthType()

SingleDataType = ctypes.c_ubyte() * 64

DataType = ctypes.SingleDataType * 1

Data = DataType()

 

ErrorCodeType = = ctypes.c_uint() * 1

ErrorCode = ErrorCodeType()

 

TickCountType = ctypes.c_ulonglong() * 1

TickCount = TickCountType()

 

MessageNum = 1

 

Ret.value = ccan.CanReceive ( Id , 1 , ctypes.byref(MessageNum) , MessageType , CanId , Data , ErrorCode , TickCount)
 

See Also

CanTransmit