STM32F042-Drivers-Pub/can.c

/*!
 * @file can.c
 * @author Francesco Gritti
 * @brief can peripheral driver implementation
 *
 * This files implements all CAN bus funcitonalities
 *
 *
 * */


#include "mcu.h"

#ifdef use_can

#include "can.h"
#include <fifo.h>
#include <string.h>




//#define CAN_IMPLEMENT_FIFO
//#define CAN_FIFO_DEPTH
#define CAN_MINIMAL_IMPLEMENTATION





/* CAN bus Flasher

  - flashare il mcu con del nuovo codice dalla periferica can bus.
  - funzionare correttamente con altri dispositivi connessi al bus
  - error detection / retransmission


  STRUTTURA CODICE

  - è necessario che TUTTO il codice eseguito durante la fase di programmazione sia
    caricato in RAM => Anche l' Interrupt Handler, il codice per inviare dati sul CAN
    e qualsiasi di queste cose. Durante la fase di programmazione è fondamentale
    assicurarsi che non vengano lanciati interrupt o altro da periferiche (a parte il CAN)
    => DISABILITO INTERRUPT QUANDO ENTRO IN ROUTINE PROGRAMMAZIONE


  PROCEDURA


  1) il rpogrammatore invia il comando PROGRAMMING_INIT con payload l'ID
  	 del dispositivo che si vuole riprogrammare

  2) Il dispositivo corrispondente entra nella routine can_flasher_SRAM
     mentre tutti gli altri smettono di inviare comandi sul can bus dal
     momento che questo potrebbe interferire o rallentare la procedura di
     caricamento del nuovo firmware

  3) il programmatore invia ogni un pacchetto da 8 byte alla volta e attende
     l'ACK del dispositivo che si sta riprogrammando. Questo è necessario
     poichè lo standard CAN richiede che ogni dispositivo connesso alla rete
     invii un messaggio di acknowledge quando riceve un messaggio con CRC corretto,
     anche se non è tra i suoi filtri.

  3-b) in caso di errore, sia che venga ricevuto un NACK al messaggio CAN,
  	   sia che NON venga ricevuto alcun messaggio da parte del sispositivo
  	   in programmazione si prova a reinviare il blocco dati per un numero N
  	   di volte

   4) una volta inviato l'intero firmware, il programmator einvia il comando
   	  PROGRAMMING_EXIT con cui notifica al dispositivo di resettarsi e a tutti
   	  gli altri di riprendere le loro normali funzioni

 * */



#ifdef CAN_IMPLEMENT_FIFO
FIFO_CREATE(canMessage_t, CAN_TxFIFO, CAN_FIFO_DEPTH);
#endif


/* Static functions */
static u8 	s_mailbox_transmit (u8 mbx, u16 ID, u8 * data, u8 len, canIdExtension idType, canDataRemote dataRemote);
static u8 	s_abort_mailbox_transmit (u8 mbx);
static void s_can_read_message (u8 mailbox);




__attribute__ ((weak)) void CAN_TxOverride (void) {}
__attribute__ ((weak)) void CAN_busError (void) {}
__attribute__ ((weak)) void CAN_onNACK (canMessage_t *message) {(void) message;}
__attribute__ ((weak)) void can_message_received (canMessage_t *message) {(void) message;}







canNetworkStatus_t can_get_network_status () {

	canNetworkStatus_t netStat = {
		.TEC = 			(CAN->ESR & CAN_ESR_TEC_Msk) >> CAN_ESR_TEC_Pos,
		.REC = 			(CAN->ESR & CAN_ESR_REC_Msk) >> CAN_ESR_REC_Pos,
		.error_warning = (CAN->ESR & CAN_ESR_BOFF_Msk)>> CAN_ESR_BOFF_Pos,
		.error_passive =	(CAN->ESR & CAN_ESR_EPVF_Msk)>> CAN_ESR_EPVF_Pos,
		.bus_off = 		(CAN->ESR & CAN_ESR_EWGF_Msk)>> CAN_ESR_EWGF_Pos,
		.LEC = 			(CAN->ESR & CAN_ESR_LEC_Msk) >> CAN_ESR_LEC_Pos,
	};
	return netStat;
}




void CEC_CAN_IRQHandler (void) {


	// check if there are messages to be read in FIFO0 and FIFO1
	u8 nMessagesFIFO0 = (CAN->RF0R & CAN_RF0R_FMP0_Msk) >> CAN_RF0R_FMP0_Pos;
	u8 nMessagesFIFO1 = (CAN->RF1R & CAN_RF1R_FMP1_Msk) >> CAN_RF1R_FMP1_Pos;

	for (; nMessagesFIFO0>0; nMessagesFIFO0--) {
		s_can_read_message (0);
		CAN->RF0R |= CAN_RF0R_RFOM0;
	}
	for (; nMessagesFIFO1>0; nMessagesFIFO1--) {
		s_can_read_message (1);
		CAN->RF1R |= CAN_RF1R_RFOM1;
	}


#ifdef CAN_IMPLEMENT_FIFO

	// check if one of the mailbox has completed transmission
	if ((CAN->TSR & (CAN_TSR_TXOK0 | CAN_TSR_TXOK1 | CAN_TSR_TXOK2)) != 0) {

		// clear all mailboxes status flag
		CAN->TSR |= CAN_TSR_RQCP0 | CAN_TSR_RQCP1 | CAN_TSR_RQCP2;

		if (!FIFO_isEmpty (&CAN_TxFIFO)) {
			// get the message from FIFO
			canMessage_t *message = (canMessage_t*) FIFO_Pop (&CAN_TxFIFO);
			// make sure pointer is valid
			if (message != 0) {

				u8 mbxCode = (CAN->TSR & (CAN_TSR_CODE_Msk)) >> CAN_TSR_CODE_Pos;
				// make sure that a mailbox is actually free. If it is, it is the one identified
				// by mbxCode
				if ((CAN->TSR & (CAN_TSR_TME0_Msk | CAN_TSR_TME1_Msk | CAN_TSR_TME2_Msk)) != 0) {

					s_mailbox_transmit (mbxCode,message->id, message->data, message->data_len, message->std_ext_id, message->data_remote_frame);
				}
				else {
					FIFO_Append (&CAN_TxFIFO, (u8*)message);
				}
			}
		}
	}
#endif
}

void s_can_read_message (u8 mailbox) {

	canMessage_t rxMessage;
	rxMessage.std_ext_id = (CAN->sFIFOMailBox[mailbox].RIR & CAN_RI0R_IDE) != 0;
	rxMessage.data_remote_frame = (CAN->sFIFOMailBox[mailbox].RIR & CAN_RI0R_RTR) != 0;
	rxMessage.id = (rxMessage.std_ext_id == canSTD_ID ? (CAN->sFIFOMailBox[mailbox].RIR & CAN_RI0R_STID) >> CAN_RI0R_STID_Pos :
											            (CAN->sFIFOMailBox[mailbox].RIR & CAN_RI0R_EXID) >> CAN_RI0R_EXID_Pos);

	rxMessage.data_len = (CAN->sFIFOMailBox[mailbox].RDTR & CAN_RDT0R_DLC_Msk) >> CAN_RDT0R_DLC_Pos;

	rxMessage.data [0] = (CAN->sFIFOMailBox[mailbox].RDLR & CAN_RDL0R_DATA0) >> CAN_RDL0R_DATA0_Pos;
	rxMessage.data [1] = (CAN->sFIFOMailBox[mailbox].RDLR & CAN_RDL0R_DATA1) >> CAN_RDL0R_DATA1_Pos;
	rxMessage.data [2] = (CAN->sFIFOMailBox[mailbox].RDLR & CAN_RDL0R_DATA2) >> CAN_RDL0R_DATA2_Pos;
	rxMessage.data [3] = (CAN->sFIFOMailBox[mailbox].RDLR & CAN_RDL0R_DATA3) >> CAN_RDL0R_DATA3_Pos;

	rxMessage.data [4] = (CAN->sFIFOMailBox[mailbox].RDHR & CAN_RDH0R_DATA4) >> CAN_RDH0R_DATA4_Pos;
	rxMessage.data [5] = (CAN->sFIFOMailBox[mailbox].RDHR & CAN_RDH0R_DATA5) >> CAN_RDH0R_DATA5_Pos;
	rxMessage.data [6] = (CAN->sFIFOMailBox[mailbox].RDHR & CAN_RDH0R_DATA6) >> CAN_RDH0R_DATA6_Pos;
	rxMessage.data [7] = (CAN->sFIFOMailBox[mailbox].RDHR & CAN_RDH0R_DATA7) >> CAN_RDH0R_DATA7_Pos;
	can_message_received (&rxMessage);
}





i8 can_init (void) {

	RCC_CAN1_CLK_ENABLE();

	// configure GPIO
	GPIO_AF_PP (CAN_TX);
	GPIO_AF_PP (CAN_RX);
	GPIO_SET_AFRH (CAN_TX, 0x04);
	GPIO_SET_AFRH (CAN_RX, 0x04);


	// enter initialization mode
	u32 startTick = flib_GetTick();
	CAN->MCR |= CAN_MCR_INRQ;

	// wait 10ms for the CAN peripheral to enter initialization mode
	// otherwise, return error
	while ((CAN->MSR & CAN_MSR_INAK) == 0U) {
		if((flib_GetTick() - startTick) > 10)
			return CAN_INIT_ERROR;
	}
	CAN->MCR &= ~CAN_MCR_SLEEP;
	//CAN_BTR_LBKM
	CAN->BTR = ((CAN_SJW-1) << CAN_BTR_SJW_Pos) | ((CAN_SEG2-1) << CAN_BTR_TS2_Pos) | ((CAN_SEG1-1) << CAN_BTR_TS1_Pos) | ((CAN_PRESCALER-1) << CAN_BTR_BRP_Pos);

	// enable interrupt on error and on FIFO 0/1 not empty and TX request complete (abort or transmit)
	CAN->IER = CAN_IER_ERRIE | CAN_IER_FMPIE1 | CAN_IER_FMPIE0 | CAN_IER_TMEIE;
	//CAN->MSR |= CAN_MSR_ERRI;

	// enable interrupt request
	NVIC_SetPriority(CEC_CAN_IRQn, 2);
	NVIC_EnableIRQ(CEC_CAN_IRQn);

	// enter normal mode. Do not wait for peripheral acknowledge since if there
	// are transmissions going on on the bus it might take a while for the
	// peripheral to enter normal mode and it is not necessary to wait
	CAN->MCR &= ~CAN_MCR_INRQ;

	return CAN_INIT_OK;
}



void can_init_minimal (void) {

	RCC_CAN1_CLK_ENABLE();

	// configure GPIO
	GPIO_AF_PP (CAN_TX);
	GPIO_AF_PP (CAN_RX);
	GPIO_SET_AFRH (CAN_TX, 0x04);
	GPIO_SET_AFRH (CAN_RX, 0x04);


	CAN->MCR |= CAN_MCR_INRQ;

	while ((CAN->MSR & CAN_MSR_INAK) == 0U);
	CAN->MCR &= ~CAN_MCR_SLEEP;
	//CAN_BTR_LBKM
	CAN->BTR = ((CAN_SJW-1) << CAN_BTR_SJW_Pos) | ((CAN_SEG2-1) << CAN_BTR_TS2_Pos) | ((CAN_SEG1-1) << CAN_BTR_TS1_Pos) | ((CAN_PRESCALER-1) << CAN_BTR_BRP_Pos);

	// enable interrupt on error and on FIFO 0/1 not empty and TX request complete (abort or transmit)
	CAN->IER = CAN_IER_ERRIE | CAN_IER_FMPIE1 | CAN_IER_FMPIE0 | CAN_IER_TMEIE;

	// enable interrupt request
	NVIC_SetPriority(CEC_CAN_IRQn, 2);
	NVIC_EnableIRQ(CEC_CAN_IRQn);

	CAN->MCR &= ~CAN_MCR_INRQ;
	// wait for peripheral to enter normal mode
}







i8 can_transmit_f32 (u16 ID, f32 data, canIdExtension idType, canDataRemote dataRemote, canTxOverrideBehaviorE override) {

	f32 localData = data;
	u8 *buffer = (u8*) (&localData);
	return can_transmit (ID, buffer, 4, idType, dataRemote, override);
}


i8 can_transmit_u32 (u16 ID, u32 data, canIdExtension idType, canDataRemote dataRemote, canTxOverrideBehaviorE override) {

	u32 localData = data;
	u8 *buffer = (u8*) (&localData);
	return can_transmit (ID, buffer, 4, idType, dataRemote, override);
}

f32 can_extract_f32 (u8 *payload) {

	f32* data = (f32*) (payload);
	return *data;
}
u32 can_extract_u32 (u8 *payload) {

	u32* data = (u32*) (payload);
	return *data;
}





// with 16bit registers only STD IDs can be mapped
u8 can_config_filter_mask_mode_16bit (u8 filterId, canFIFO assignedFIFO, canDataRemote dataRemote, u16 id1, u16 id2, u16 mask1, u16 mask2) {

	if (filterId >= N_FILTERS)
		return 0;

	u32 filterBitMask = (u32)(1 << filterId);

	// deactivate filter
	CAN->FA1R &= ~filterBitMask;
	// enter filter configuration mode
	CAN->FMR |= CAN_FMR_FINIT;

	// set mask mode
	CAN->FM1R &= ~ filterBitMask;
	// set scale mode to 16 bit
	CAN->FS1R &= ~ filterBitMask;


	u32 mask1_reg = ((u32)mask1 << 5);
	u32 id1_reg = ((u32) id1 << 5);
	u32 mask2_reg = ((u32)mask2 << 5);
	u32 id2_reg = ((u32) id2 << 5);
	if (dataRemote == canREMOTE_FRAME) {
		mask1_reg |= (1 << 4);
		id1_reg |= (1 << 4);
		mask2_reg |= (1 << 4);
		id2_reg |= (1 << 4);
	}

	CAN->sFilterRegister [filterId].FR1 = (mask1_reg << 16) | id1_reg;
	CAN->sFilterRegister [filterId].FR2 = (mask2_reg << 16) | id2_reg;

	// assign FIFO
	if (assignedFIFO == canFIFO_0)
		CAN->FFA1R &= ~filterBitMask;
	else
		CAN->FFA1R |= filterBitMask;

	CAN->FMR &= ~CAN_FMR_FINIT;

	return 1;
}


// can map both STD and EXTENDED IDs
u8 can_config_filter_mask_mode_32bit (u8 filterId, canFIFO assignedFIFO, canIdExtension extendedId, canDataRemote dataRemote, u32 id, u32 mask) {


	if (filterId >= N_FILTERS)
		return 0;

	u32 filterBitMask = (u32)(1 << filterId);

	// deactivate filter
	CAN->FA1R &= ~filterBitMask;
	// enter filter configuration mode
	CAN->FMR |= CAN_FMR_FINIT;

	// set mask mode
	CAN->FM1R &= ~ filterBitMask;
	// set scale mode to 32 bit
	CAN->FS1R |= filterBitMask;

	if (extendedId == canSTD_ID) {
		CAN->sFilterRegister [filterId].FR1 = ((u32)id << 21);
		CAN->sFilterRegister [filterId].FR2 = ((u32)mask << 21);
	}
	else {
		CAN->sFilterRegister [filterId].FR1 = ((u32)id << 3) | (1 << 2);
		CAN->sFilterRegister [filterId].FR2 = ((u32)mask << 3) | (1 << 2);

		if (dataRemote == canREMOTE_FRAME) {
			CAN->sFilterRegister [filterId].FR1 |= (1<<1);
			CAN->sFilterRegister [filterId].FR2 |= (1<<1);
		}
	}

	// assign FIFO
	if (assignedFIFO == canFIFO_0)
		CAN->FFA1R &= ~filterBitMask;
	else
		CAN->FFA1R |= filterBitMask;

	CAN->FMR &= ~CAN_FMR_FINIT;

	return 1;
}



u8 can_config_filter_list_mode_16bit (u8 filterId, canFIFO assignedFIFO, canDataRemote dataRemote, u16 id1, u16 id2, u16 id3, u16 id4) {

	if (filterId >= N_FILTERS)
		return 0;

	u32 filterBitMask = (u32)(1 << filterId);

	CAN->FA1R &= ~filterBitMask;	// deactivate filter
	CAN->FMR |= CAN_FMR_FINIT;		// enter filter configuration mode

	CAN->FM1R |= filterBitMask;		// set list mode
	CAN->FS1R &= ~ filterBitMask;	// set scale mode to 16 bit


	u32 id1_reg = ((u32)id1 << 5);
	u32 id2_reg = ((u32)id2 << 5);
	u32 id3_reg = ((u32)id3 << 5);
	u32 id4_reg = ((u32)id4 << 5);
	if (dataRemote == canREMOTE_FRAME) {
		id1_reg |= (1 << 4);
		id2_reg |= (1 << 4);
		id3_reg |= (1 << 4);
		id4_reg |= (1 << 4);
	}

	CAN->sFilterRegister [filterId].FR1 = (id1_reg << 16) | id2_reg;
	CAN->sFilterRegister [filterId].FR2 = (id3_reg << 16) | id4_reg;

	// assign FIFO
	if (assignedFIFO == canFIFO_0)
		CAN->FFA1R &= ~filterBitMask;
	else
		CAN->FFA1R |= filterBitMask;

	CAN->FMR &= ~CAN_FMR_FINIT;

	return 1;
}


u8 can_config_filter_list_mode_32bit (u8 filterId, canFIFO assignedFIFO, canIdExtension extendedId, canDataRemote dataRemote, u32 id1, u32 id2) {


	if (filterId >= N_FILTERS)
		return 0;

	u32 filterBitMask = (u32)(1 << filterId);

	CAN->FA1R &= ~filterBitMask;	// deactivate filter
	CAN->FMR |= CAN_FMR_FINIT;		// enter filter configuration mode

	CAN->FM1R |= filterBitMask;		// set list mode
	CAN->FS1R |= filterBitMask;		// set scale mode to 32 bit

	if (extendedId == canSTD_ID) {
		CAN->sFilterRegister [filterId].FR1 = (id1 << 21);
		CAN->sFilterRegister [filterId].FR2 = (id2 << 21);
	}
	else {
		CAN->sFilterRegister [filterId].FR1 = (id1 << 3) | (1 << 2);
		CAN->sFilterRegister [filterId].FR2 = (id2 << 3) | (1 << 2);

		if (dataRemote == canREMOTE_FRAME) {
			CAN->sFilterRegister [filterId].FR1 |= (1<<1);
			CAN->sFilterRegister [filterId].FR2 |= (1<<1);
		}
	}

	// assign FIFO
	if (assignedFIFO == canFIFO_0)
		CAN->FFA1R &= ~filterBitMask;
	else
		CAN->FFA1R |= filterBitMask;

	CAN->FMR &= ~CAN_FMR_FINIT;
	return 1;
}





void can_enable_filter (u8 filterId) {

	if (filterId >= N_FILTERS)
		return;
	CAN->FA1R |= (u32)(1<<filterId);
}
void can_disable_filter (u8 filterId) {

	if (filterId >= N_FILTERS)
		return;
	CAN->FA1R &= ~ (u32)(1<<filterId);
}










i8 can_transmit (u16 ID, u8 * data, u8 len, canIdExtension idType, canDataRemote dataRemote, canTxOverrideBehaviorE override) {

	if (idType != canSTD_ID && idType != canEXTENDED_ID)
		return -1;
	if (dataRemote != canDATA_FRAME && dataRemote != canREMOTE_FRAME)
		return -1;
	if (len > 8 || len == 0)
		return -1;


	// check if the mailbox addressed by
	u8 mbxCode = (CAN->TSR & (CAN_TSR_CODE_Msk)) >> CAN_TSR_CODE_Pos;

	// check if at least one mailbox is free. In this case, its id is the one
	// previously read from CAN_TSR <CODE>
	if ((CAN->TSR & (CAN_TSR_TME0_Msk | CAN_TSR_TME1_Msk | CAN_TSR_TME2_Msk)) != 0) {

		s_mailbox_transmit (mbxCode, ID, data, len, idType, dataRemote);
		return CAN_TX_OK;
	}

	// in case none of the mailbox is free, if OVERRIDE LOW PRIO flag was set, look
	// for the mailbox with the message of lowest priority, abort its transmission
	// and request the transmission of the new message. The mailbox code with lowest
	// priority is the one read from CAN_TSR <CODE>
	else if (override == CAN_OVERRIDE_LOW_PRIO) {

		if (s_abort_mailbox_transmit (mbxCode) && s_mailbox_transmit ((mbxCode-1), ID, data, len, idType, dataRemote)) {
			return CAN_TX_OK;
		}
		return CAN_TX_ERROR;
	}


	else if (override == CAN_OVERRIDE_IF_HIGHER_PRIO) {

		// get lowest priority mailbox message ID type (STD or extended)
		u8 mbxIdType = (CAN->sTxMailBox [mbxCode].TIR & CAN_TI0R_IDE_Msk) >> CAN_TI0R_IDE_Pos;

		// make sure the two messages have the same ID type (STD or extended)
		if (mbxIdType == idType) {

			// standard address case
			if (mbxIdType == 0) {
				u16 stdId = (CAN->sTxMailBox [mbxCode].TIR & CAN_TI0R_STID_Msk) >> CAN_TI0R_STID_Pos;

				// in case the message for which transmission was requested has higher priority,
				// abort transmission of the previous and request transmission of the current one
				if (ID < stdId) {
					if (s_abort_mailbox_transmit (mbxCode) &&
						s_mailbox_transmit (mbxCode-1, ID, data, len, idType, dataRemote)) {
						return CAN_TX_OK;
					}
					return CAN_TX_ERROR;
				}
			}

			// extended address
			else {
				u32 extID = (CAN->sTxMailBox [mbxCode].TIR & CAN_TI0R_EXID_Msk) >> CAN_TI0R_EXID_Pos;
				if (ID < extID) {
					if (s_abort_mailbox_transmit (mbxCode) &&
						s_mailbox_transmit (mbxCode-1, ID, data, len, idType, dataRemote)) {
						return CAN_TX_OK;
					}
					return CAN_TX_ERROR;
				}
			}

		}
	}

	else if (override == CAN_OVERRIDE_ID) {

		// look for the given ID in the transmit mailboxes

		for (u8 mbx=0; mbx <3; mbx++) {

			u8 mbxExtId = (CAN->sTxMailBox [mbxCode].TIR & CAN_TI0R_IDE_Msk) >> CAN_TI0R_IDE_Pos;

			if (mbxExtId == idType) {

				if (mbxExtId) {
					u32 extId = (CAN->sTxMailBox [mbxCode].TIR & CAN_TI0R_EXID_Msk) >> CAN_TI0R_EXID_Pos;
					if (extId == ID) {
						if (s_abort_mailbox_transmit (mbxCode) &&
							s_mailbox_transmit (mbxCode-1, ID, data, len, idType, dataRemote)) {
							return CAN_TX_OK;
						}
						return CAN_TX_ERROR;
					}
				}
				else {
					u16 stdId = (CAN->sTxMailBox [mbxCode].TIR & CAN_TI0R_STID_Msk) >> CAN_TI0R_STID_Pos;
					if (stdId == ID) {
						if (s_abort_mailbox_transmit (mbxCode) &&
						    s_mailbox_transmit (mbxCode-1, ID, data, len, idType, dataRemote)) {
							return CAN_TX_OK;
						}
						return CAN_TX_ERROR;
					}
				}
			}
		}
	}
	// if none of the previous transmits were successful, append the message to the FIFO

	// disable CAN interrupt so that ISR cannot change FIFO content while updating here
	// NOTE: it is important disable all CAN interrupt since inside ISR the flag for TX
	// complete is always checked, even if the actual source if the interrupt was another
	// flag.
	NVIC_DisableIRQ(CEC_CAN_IRQn);


#ifdef CAN_IMPLEMENT_FIFO
	if (!FIFO_isFull (&CAN_TxFIFO)) {

		// construct the message
		canMessage_t message = {
			.std_ext_id = idType,
			.data_remote_frame = dataRemote,
			.id = ID,
			.data_len = len
		};
		memcpy (message.data, data, len);
		FIFO_Append (&CAN_TxFIFO, (u8*)&message);
		NVIC_EnableIRQ(CEC_CAN_IRQn);
		return CAN_TX_OK;
	}
	else {
		NVIC_EnableIRQ(CEC_CAN_IRQn);
		CAN_TxOverride ();
		return CAN_TX_ERROR;
	}
#endif

	return CAN_TX_ERROR;
}




void can_enable_automatic_retransmission (void) {
	// write to MCR register can be done outside initialization mode
	CAN->MCR &= ~CAN_MCR_NART;
}

void can_desable_automatic_retransmission (void) {

	CAN->MCR |= CAN_MCR_NART;
}








u8 s_abort_mailbox_transmit (u8 mbx) {

	u32 abortMAsk = 0;
	u32 testMask = 0;

	switch (mbx) {
	case 1:
		abortMAsk = CAN_TSR_ABRQ0_Msk;
		testMask = CAN_TSR_TME0_Msk;
		break;

	case 2:
		abortMAsk = CAN_TSR_ABRQ1_Msk;
		testMask = CAN_TSR_TME1_Msk;
		break;

	case 3:
		abortMAsk = CAN_TSR_ABRQ2_Msk;
		testMask = CAN_TSR_TME2_Msk;
		break;
	default:
		return 0;
	}

	CAN->TSR |= abortMAsk;

	u32 startTick = flib_GetTick ();
	while ((CAN->TSR & testMask) == 0) {
		if((flib_GetTick() - startTick) > 10)
			return 0; // flag error
	}

	return 1;
}


u8 s_mailbox_transmit (u8 mbx, u16 ID, u8 * data, u8 len, canIdExtension idType, canDataRemote dataRemote) {

	// make sure the mailbox is actually free
	if (mbx >= 3 || (CAN->TSR & (CAN_TSR_TME0_Msk << mbx)) == 0)
		return 0;

	CAN->sTxMailBox[mbx].TIR = ID << (idType == canSTD_ID ? CAN_TI0R_STID_Pos : CAN_TI0R_EXID_Pos);
	if (idType == canEXTENDED_ID)
		CAN->sTxMailBox[mbx].TIR |= CAN_TI0R_IDE_Msk;
	if (dataRemote == canREMOTE_FRAME)
		CAN->sTxMailBox[mbx].TIR |= CAN_TI0R_RTR_Msk;

	// set data length register
	CAN->sTxMailBox[mbx].TDTR = (len & 0x0f);

	// reset data registers
	CAN->sTxMailBox[mbx].TDLR = 0x0000;
	CAN->sTxMailBox[mbx].TDHR = 0x0000;

	CAN->sTxMailBox[mbx].TDLR |= data[0];
	if (len > 1)
		CAN->sTxMailBox[mbx].TDLR |= (data[1] << 8);
	if (len > 2)
		CAN->sTxMailBox[mbx].TDLR |= (data[2] << 16);
	if (len > 3)
		CAN->sTxMailBox[mbx].TDLR |= (data[3] << 24);
	if (len > 4)
		CAN->sTxMailBox[mbx].TDHR |= data[4];
	if (len > 5)
		CAN->sTxMailBox[mbx].TDHR |= (data[5] << 8);
	if (len > 6)
		CAN->sTxMailBox[mbx].TDHR |= (data[6] << 16);
	if (len > 7)
		CAN->sTxMailBox[mbx].TDHR |= (data[7] << 24);

	// request transmission
	CAN->sTxMailBox[mbx].TIR |= CAN_TI0R_TXRQ_Msk;
	return 1;
}


#endif