CAN - Controller Area Network
Description
Controller Area Network API.
The Controller Area Network Interface Bus (CAN) implements a multi-master serial bus for connecting microcontrollers and devices, also known as nodes, to communicate with each other in applications without a host computer. CAN is a message-based protocol, designed originally for automotive applications, but also used in many other scenarios. The complexity of a node can range from a simple I/O device up to an embedded computer with a CAN interface and sophisticated software. The node may also be a gateway allowing a standard computer to communicate over a USB or Ethernet port to the devices on a CAN network. Devices are connected to the bus through a host processor, a CAN controller, and a CAN transceiver.
Data Structures |
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struct | CAN_MessageObject_TypeDef |
CAN Message Object TypeDef structure.
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struct | CAN_Init_TypeDef |
CAN initialization structure.
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Functions |
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void | CAN_Init (CAN_TypeDef *can, const CAN_Init_TypeDef *init) |
Initialize CAN.
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uint32_t | CAN_GetClockFrequency (CAN_TypeDef *can) |
Get the CAN module frequency.
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bool | CAN_MessageLost (CAN_TypeDef *can, uint8_t interface, uint8_t msgNum) |
Read a Message Object to find if a message was lost ; reset the 'Message Lost' flag.
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void | CAN_SetRoute (CAN_TypeDef *can, bool active, uint16_t pinRxLoc, uint16_t pinTxLoc) |
Set the ROUTE registers.
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void | CAN_SetBitTiming (CAN_TypeDef *can, uint32_t bitrate, uint16_t propagationTimeSegment, uint16_t phaseBufferSegment1, uint16_t phaseBufferSegment2, uint16_t synchronisationJumpWidth) |
Set the bitrate and its parameters.
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void | CAN_SetMode (CAN_TypeDef *can, CAN_Mode_TypeDef mode) |
Set the CAN operation mode.
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void | CAN_SetIdAndFilter (CAN_TypeDef *can, uint8_t interface, bool useMask, const CAN_MessageObject_TypeDef *message, bool wait) |
Set the ID and the filter for a specific Message Object.
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void | CAN_ConfigureMessageObject (CAN_TypeDef *can, uint8_t interface, uint8_t msgNum, bool valid, bool tx, bool remoteTransfer, bool endOfBuffer, bool wait) |
Configure valid, TX/RX, remoteTransfer for a specific Message Object.
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void | CAN_SendMessage (CAN_TypeDef *can, uint8_t interface, const CAN_MessageObject_TypeDef *message, bool wait) |
Send data from the Message Object message.
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bool | CAN_ReadMessage (CAN_TypeDef *can, uint8_t interface, CAN_MessageObject_TypeDef *message) |
Read data and ID from a Message Object in RAM and store it in a message.
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void | CAN_AbortSendMessage (CAN_TypeDef *can, uint8_t interface, uint8_t msgNum, bool wait) |
Abort sending a message.
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void | CAN_ResetMessages (CAN_TypeDef *can, uint8_t interface) |
Reset all Message Objects and set their data to 0.
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void | CAN_Reset (CAN_TypeDef *can) |
Set all CAN registers to RESETVALUE.
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void | CAN_WriteData (CAN_TypeDef *can, uint8_t interface, const CAN_MessageObject_TypeDef *message) |
Write data from a message to the MIRx registers.
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void | CAN_SendRequest (CAN_TypeDef *can, uint8_t interface, uint8_t msgNum, bool wait) |
Send a request for writing or reading RAM of the Message Object msgNum.
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void | CAN_Enable (CAN_TypeDef *can, bool enable) |
Enable the Host Controller to send messages.
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bool | CAN_IsEnabled (CAN_TypeDef *can) |
Give the communication capabilities state.
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void | CAN_ReadyWait (CAN_TypeDef *can, uint8_t interface) |
Waiting function.
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CAN_ErrorCode_TypeDef | CAN_GetLastErrorCode (CAN_TypeDef *can) |
Get the last error code and clear its register.
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uint32_t | CAN_HasNewdata (CAN_TypeDef *can) |
Indicates which message objects have received new data.
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void | CAN_StatusIntClear (CAN_TypeDef *can, uint32_t flags) |
Clear one or more pending CAN status interrupts.
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void | CAN_StatusIntDisable (CAN_TypeDef *can, uint32_t flags) |
Disable CAN status interrupts.
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void | CAN_StatusIntEnable (CAN_TypeDef *can, uint32_t flags) |
Enable CAN status interrupts.
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uint32_t | CAN_StatusIntGet (CAN_TypeDef *can) |
Get pending CAN status interrupt flags.
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uint32_t | CAN_StatusIntGetEnabled (CAN_TypeDef *can) |
Get pending and enabled CAN status interrupt flags.
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void | CAN_StatusIntSet (CAN_TypeDef *can, uint32_t flags) |
Set one or more CAN status interrupts.
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uint32_t | CAN_StatusGet (CAN_TypeDef *can) |
Get CAN status.
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void | CAN_StatusClear (CAN_TypeDef *can, uint32_t flags) |
Clear CAN status.
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uint32_t | CAN_GetErrorCount (CAN_TypeDef *can) |
Get the error count.
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void | CAN_MessageIntClear (CAN_TypeDef *can, uint32_t flags) |
Clear one or more pending CAN message interrupts.
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void | CAN_MessageIntDisable (CAN_TypeDef *can, uint32_t flags) |
Disable CAN message interrupts.
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void | CAN_MessageIntEnable (CAN_TypeDef *can, uint32_t flags) |
Enable CAN message interrupts.
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uint32_t | CAN_MessageIntGet (CAN_TypeDef *can) |
Get pending CAN message interrupt flags.
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uint32_t | CAN_MessageIntGetEnabled (CAN_TypeDef *can) |
Get CAN message interrupt flags that are pending and enabled.
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void | CAN_MessageIntSet (CAN_TypeDef *can, uint32_t flags) |
Set one or more CAN message interrupts.
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Macros |
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#define | CAN_INIT_DEFAULT |
Default initialization of
CAN_Init_TypeDef
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Enumerations |
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enum |
CAN_ErrorCode_TypeDef
{
canErrorNoError = CAN_STATUS_LEC_NONE, canErrorStuff = CAN_STATUS_LEC_STUFF, canErrorForm = CAN_STATUS_LEC_FORM, canErrorAck = CAN_STATUS_LEC_ACK, canErrorBit1 = CAN_STATUS_LEC_BIT1, canErrorBit0 = CAN_STATUS_LEC_BIT0, canErrorCrc = CAN_STATUS_LEC_CRC, canErrorUnused = CAN_STATUS_LEC_UNUSED } |
CAN Status codes.
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enum |
CAN_Mode_TypeDef
{
canModeNormal , canModeBasic , canModeLoopBack , canModeSilentLoopBack , canModeSilent } |
CAN peripheral mode.
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Function Documentation
◆ CAN_Init()
void CAN_Init | ( | CAN_TypeDef * |
can,
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const CAN_Init_TypeDef * |
init
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Initialize CAN.
- Parameters
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[in] can
A pointer to the CAN peripheral register block. [in] init
A pointer to the CAN initialization structure.
◆ CAN_GetClockFrequency()
uint32_t CAN_GetClockFrequency | ( | CAN_TypeDef * |
can
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Get the CAN module frequency.
An internal prescaler of 2 is inside the CAN module.
- Parameters
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[in] can
A pointer to the CAN peripheral register block.
- Returns
- A clock value.
◆ CAN_MessageLost()
bool CAN_MessageLost | ( | CAN_TypeDef * |
can,
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uint8_t |
interface,
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uint8_t |
msgNum
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Read a Message Object to find if a message was lost ; reset the 'Message Lost' flag.
- Parameters
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[in] can
A pointer to the CAN peripheral register block. [in] interface
Indicate which Message Interface Register to use. [in] msgNum
A message number of the Message Object, [1 - 32].
- Returns
- True if a message was lost, false otherwise.
◆ CAN_SetRoute()
void CAN_SetRoute | ( | CAN_TypeDef * |
can,
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bool |
active,
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uint16_t |
pinRxLoc,
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uint16_t |
pinTxLoc
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Set the ROUTE registers.
- Parameters
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[in] can
A pointer to the CAN peripheral register block. [in] active
A boolean indicating whether or not to activate the ROUTE registers. [in] pinRxLoc
A location of the RX pin. [in] pinTxLoc
A location of the TX pin.
◆ CAN_SetBitTiming()
void CAN_SetBitTiming | ( | CAN_TypeDef * |
can,
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uint32_t |
bitrate,
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uint16_t |
propagationTimeSegment,
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uint16_t |
phaseBufferSegment1,
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uint16_t |
phaseBufferSegment2,
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uint16_t |
synchronisationJumpWidth
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Set the bitrate and its parameters.
Multiple parameters need to be properly configured. See the reference manual for a detailed description. Careful : the BRP (Baud Rate Prescaler) is calculated by: 'brp = freq / (period * bitrate);'. freq is the frequency of the CAN device, period the time of transmission of a bit. The result is an uint32_t. Hence it's truncated, causing an approximation error. This error is non negligible when the period is high, the bitrate is high, and frequency is low.
- Parameters
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[in] can
A pointer to the CAN peripheral register block. [in] bitrate
A wanted bitrate on the CAN bus. [in] propagationTimeSegment
A value for the Propagation Time Segment. [in] phaseBufferSegment1
A value for the Phase Buffer Segment 1. [in] phaseBufferSegment2
A value for the Phase Buffer Segment 2. [in] synchronisationJumpWidth
A value for the Synchronization Jump Width.
◆ CAN_SetMode()
void CAN_SetMode | ( | CAN_TypeDef * |
can,
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CAN_Mode_TypeDef |
mode
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Set the CAN operation mode.
In initialization mode, the CAN module is deactivated. Reset the messages in all other modes to be sure that there is no leftover data that needs to be configured before use.
- Parameters
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[in] can
A pointer to the CAN peripheral register block. [in] mode
Mode of operation : Init, Normal, Loopback, SilentLoopback, Silent, Basic.
◆ CAN_SetIdAndFilter()
void CAN_SetIdAndFilter | ( | CAN_TypeDef * |
can,
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uint8_t |
interface,
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bool |
useMask,
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const CAN_MessageObject_TypeDef * |
message,
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bool |
wait
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Set the ID and the filter for a specific Message Object.
The initialization bit has to be 0 to use this function.
- Parameters
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[in] can
A pointer to the CAN peripheral register block. [in] interface
Indicate which Message Interface Register to use. [in] useMask
A boolean to choose whether or not to use the masks. [in] message
A Message Object. [in] wait
If true, wait for the end of the transfer between the MIRx registers and the RAM to exit. If false, exit immediately, the transfer can still be in progress.
◆ CAN_ConfigureMessageObject()
void CAN_ConfigureMessageObject | ( | CAN_TypeDef * |
can,
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uint8_t |
interface,
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uint8_t |
msgNum,
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bool |
valid,
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bool |
tx,
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bool |
remoteTransfer,
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bool |
endOfBuffer,
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bool |
wait
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) |
Configure valid, TX/RX, remoteTransfer for a specific Message Object.
The initialization bit has to be 0 to use this function.
- Parameters
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[in] can
A pointer to the CAN peripheral register block. [in] interface
Indicate which Message Interface Register to use. [in] msgNum
A message number of this Message Object, [1 - 32]. [in] valid
True if the Message Object is valid, false otherwise. [in] tx
True if the Message Object is used for transmission, false if used for reception. [in] remoteTransfer
True if the Message Object is used for remote transmission, false otherwise. [in] endOfBuffer
True if it is for a single Message Object or the end of a FIFO buffer, false if the Message Object is part of a FIFO buffer and not the last. [in] wait
If true, wait for the end of the transfer between the MIRx registers and the RAM to exit. If false, exit immediately, the transfer can still be in progress.
◆ CAN_SendMessage()
void CAN_SendMessage | ( | CAN_TypeDef * |
can,
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uint8_t |
interface,
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const CAN_MessageObject_TypeDef * |
message,
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bool |
wait
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Send data from the Message Object message.
If the message is configured as TX and remoteTransfer = 0, calling this function will send the data of this Message Object if its parameters are correct. If the message is TX and remoteTransfer = 1, this function will set the data of message to RAM and exit. Data will be automatically sent after reception of a remote frame. If the message is RX and remoteTransfer = 1, this function will send a remote frame to the corresponding ID. If the message is RX and remoteTransfer = 0, the user shouldn't call this function. It will also send a remote frame.
- Parameters
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[in] can
A pointer to the CAN peripheral register block. [in] interface
Indicate which Message Interface Register to use. [in] message
A Message Object. [in] wait
If true, wait for the end of the transfer between the MIRx registers and RAM to exit. If false, exit immediately. The transfer can still be in progress.
◆ CAN_ReadMessage()
bool CAN_ReadMessage | ( | CAN_TypeDef * |
can,
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uint8_t |
interface,
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CAN_MessageObject_TypeDef * |
message
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Read data and ID from a Message Object in RAM and store it in a message.
Read the information from RAM on this Message Object. Data and the configuration of the Message Object is read. The information is only read if the message stored in the Message Object is new and valid.
- Parameters
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[in] can
A pointer to the CAN peripheral register block. [in] interface
Indicate which Message Interface Register to use. [in] message
A Message Object.
- Returns
- True if the Message Object in RAM holds a new and valid message, which was not read earlier, false otherwise.
◆ CAN_AbortSendMessage()
void CAN_AbortSendMessage | ( | CAN_TypeDef * |
can,
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uint8_t |
interface,
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uint8_t |
msgNum,
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bool |
wait
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Abort sending a message.
Set the TXRQST of the CTRL register to 0. Doesn't touch data or the other parameters. The user can call CAN_SendMessage() to send the object after using CAN_AbortSendMessage() .
- Parameters
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[in] can
A pointer to the CAN peripheral register block. [in] interface
Indicate which Message Interface Register to use. [in] msgNum
A message number of this Message Object, [1 - 32]. [in] wait
If true, wait for the end of the transfer between the MIRx registers and the RAM to exit. If false, exit immediately. The transfer can still be in progress.
◆ CAN_ResetMessages()
void CAN_ResetMessages | ( | CAN_TypeDef * |
can,
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uint8_t |
interface
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Reset all Message Objects and set their data to 0.
- Parameters
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[in] can
A pointer to the CAN peripheral register block. [in] interface
Indicate which Message Interface Register to use.
◆ CAN_Reset()
void CAN_Reset | ( | CAN_TypeDef * |
can
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Set all CAN registers to RESETVALUE.
Leave the CAN device disabled.
- Parameters
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[in] can
A pointer to the CAN peripheral register block.
◆ CAN_WriteData()
void CAN_WriteData | ( | CAN_TypeDef * |
can,
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uint8_t |
interface,
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const CAN_MessageObject_TypeDef * |
message
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Write data from a message to the MIRx registers.
- Parameters
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[in] can
A pointer to the CAN peripheral register block. [in] interface
Indicate which Message Interface Register to use. [in] message
A Message Object.
◆ CAN_SendRequest()
void CAN_SendRequest | ( | CAN_TypeDef * |
can,
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uint8_t |
interface,
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uint8_t |
msgNum,
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bool |
wait
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Send a request for writing or reading RAM of the Message Object msgNum.
- Parameters
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[in] can
A pointer to the CAN peripheral register block. [in] interface
Indicate which Message Interface Register to use. [in] msgNum
A message number of the Message Object, [1 - 32]. [in] wait
If true, wait for the end of the transfer between the MIRx registers and the RAM to exit. If false, exit immediately. The transfer can still be in progress.
◆ CAN_Enable()
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inline |
Enable the Host Controller to send messages.
- Parameters
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[in] can
A pointer to the CAN peripheral register block. [in] enable
True to enable CAN device, false to disable it. If the CAN device is enabled, it goes to normal mode (the default working mode).
◆ CAN_IsEnabled()
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inline |
Give the communication capabilities state.
- Parameters
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[in] can
A pointer to the CAN peripheral register block.
- Returns
- True if the Host Controller can send messages, false otherwise.
◆ CAN_ReadyWait()
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inline |
Waiting function.
- Parameters
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[in] can
A pointer to the CAN peripheral register block. [in] interface
Indicate which Message Interface Register to use.
◆ CAN_GetLastErrorCode()
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inline |
Get the last error code and clear its register.
- Parameters
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[in] can
Pointer to CAN peripheral register block.
- Returns
- return Last error code.
◆ CAN_HasNewdata()
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inline |
Indicates which message objects have received new data.
- Parameters
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[in] can
A pointer to the CAN peripheral register block.
- Returns
- State of MESSAGEDATA register indicating which message objects have received new data.
◆ CAN_StatusIntClear()
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inline |
Clear one or more pending CAN status interrupts.
- Parameters
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[in] can
A pointer to the CAN peripheral register block. [in] flags
Pending CAN status interrupt source(s) to clear.
◆ CAN_StatusIntDisable()
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inline |
Disable CAN status interrupts.
- Parameters
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[in] can
A pointer to the CAN peripheral register block. [in] flags
CAN status interrupt source(s) to disable.
◆ CAN_StatusIntEnable()
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inline |
Enable CAN status interrupts.
- Parameters
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[in] can
A pointer to the CAN peripheral register block. [in] flags
CAN status interrupt source(s) to enable.
◆ CAN_StatusIntGet()
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inline |
Get pending CAN status interrupt flags.
- Note
- This function does not clear event bits.
- Parameters
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[in] can
A pointer to the CAN peripheral register block.
- Returns
- CAN interrupt source(s) pending.
◆ CAN_StatusIntGetEnabled()
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inline |
Get pending and enabled CAN status interrupt flags.
- Note
- This function does not clear event bits.
- Parameters
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[in] can
A pointer to the CAN peripheral register block.
- Returns
- CAN interrupt source(s) pending and enabled.
◆ CAN_StatusIntSet()
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inline |
Set one or more CAN status interrupts.
- Parameters
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[in] can
A pointer to the CAN peripheral register block. [in] flags
CAN status interrupt source(s) to set to pending.
◆ CAN_StatusGet()
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inline |
Get CAN status.
- Parameters
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[in] can
A pointer to the CAN peripheral register block.
- Returns
- A value of CAN register STATUS.
◆ CAN_StatusClear()
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inline |
Clear CAN status.
- Parameters
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[in] can
A pointer to the CAN peripheral register block. [in] flags
CAN status bits to clear.
◆ CAN_GetErrorCount()
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inline |
Get the error count.
- Parameters
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[in] can
A pointer to the CAN peripheral register block.
- Returns
- Error count.
◆ CAN_MessageIntClear()
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inline |
Clear one or more pending CAN message interrupts.
- Parameters
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[in] can
A pointer to the CAN peripheral register block. [in] flags
Pending CAN message interrupt source(s) to clear.
◆ CAN_MessageIntDisable()
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inline |
Disable CAN message interrupts.
- Parameters
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[in] can
A pointer to the CAN peripheral register block. [in] flags
CAN message interrupt source(s) to disable.
◆ CAN_MessageIntEnable()
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inline |
Enable CAN message interrupts.
- Parameters
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[in] can
A pointer to the CAN peripheral register block. [in] flags
CAN message interrupt source(s) to enable.
◆ CAN_MessageIntGet()
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inline |
Get pending CAN message interrupt flags.
- Note
- This function does not clear event bits.
- Parameters
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[in] can
A pointer to the CAN peripheral register block.
- Returns
- CAN message interrupt source(s) pending.
◆ CAN_MessageIntGetEnabled()
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inline |
Get CAN message interrupt flags that are pending and enabled.
- Note
- This function does not clear event bits.
- Parameters
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[in] can
A pointer to the CAN peripheral register block.
- Returns
- CAN message interrupt source(s) pending and enabled.
◆ CAN_MessageIntSet()
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inline |
Set one or more CAN message interrupts.
- Parameters
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[in] can
A pointer to the CAN peripheral register block. [in] flags
CAN message interrupt source(s) to set as pending.
Macro Definition Documentation
◆ CAN_INIT_DEFAULT
#define CAN_INIT_DEFAULT |
Default initialization of CAN_Init_TypeDef .
The total duration of a bit with these default parameters is 10 tq (time quantum : tq = brp/fsys, brp being the baudrate prescaler and being set according to the wanted bitrate, fsys beeing the CAN device frequency).
Enumeration Type Documentation
◆ CAN_ErrorCode_TypeDef
CAN Status codes.
◆ CAN_Mode_TypeDef
enum CAN_Mode_TypeDef |
CAN peripheral mode.