Flexcan problem on KE1xF

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Flexcan problem on KE1xF

Contributor I

HI, I'm developing an application with a KE16F256. I generated the sdk with pins and clock and inside I found examples for the TWR-KE18F evaluation board. I tried to use the loopback, loopback transfer and interrupt examples but without any success. I'm not able to send / receive. If I use the blocking tx the tx function hangs. The only thing that seems working is that when I set the loopback on, everytime I call the non blocking transfer I have my callback called to notify the TX idle.

I configured correctly Tx and Rx pin alternate function. I enabled the clock for the flexcan.

I'm quite new to kinetis world (I'm coming from STM32). 

Is there a check list to see if I'm not fogotting something?

Just for reference I attach some code:

this is the can init function:

void flexcan_configure(uint32_t baudRate)

/* Init FlexCAN module. */
flexcan_config_t flexcanConfig;
flexcan_rx_mb_config_t mbConfig;
* flexcanConfig.clkSrc = kFLEXCAN_ClkSrcOsc;
* flexcanConfig.baudRate = 125000U;
* flexcanConfig.maxMbNum = 16;
* flexcanConfig.enableLoopBack = false;
* flexcanConfig.enableSelfWakeup = false;
* flexcanConfig.enableIndividMask = false;
* flexcanConfig.enableDoze = false;
flexcanConfig.clkSrc = kFLEXCAN_ClkSrcPeri;
flexcanConfig.enableLoopBack = true;
flexcanConfig.baudRate = baudRate;

FLEXCAN_Init(CAN_IF, &flexcanConfig, CAN_CLK_FREQ);

/* Create FlexCAN handle structure and set call back function. */
FLEXCAN_TransferCreateHandle(CAN_IF, &flexcanHandle, flexcan_callback, NULL);

/* Enable Rx Message Buffer interrupt. */

/* Setup Rx Message Buffer. */
mbConfig.format = kFLEXCAN_FrameFormatStandard;
mbConfig.type = kFLEXCAN_FrameTypeData;
mbConfig.id = FLEXCAN_ID_STD(0x680);
FLEXCAN_SetRxMbConfig(CAN_IF, RX_MESSAGE_BUFFER_NUM, &mbConfig, true);

/* Setup Tx Message Buffer. */

// /* Enable Rx Message Buffer interrupt. */
// FLEXCAN_EnableMbInterrupts(CAN_IF, 1 << RX_MESSAGE_BUFFER_NUM);
// EnableIRQ(CAN_IRQn);


 this is my send function:

void flexcan_send(uint16_t ID, uint8_t data[8],uint8_t DLC)
/* Prepare Tx Frame for sending. */
txFrame.format = kFLEXCAN_FrameFormatStandard;
txFrame.type = kFLEXCAN_FrameTypeData;
txFrame.id = FLEXCAN_ID_STD(ID);
txFrame.length = DLC;
txFrame.dataWord0 = CAN_WORD0_DATA_BYTE_0(data[0]) | CAN_WORD0_DATA_BYTE_1(data[1]) | CAN_WORD0_DATA_BYTE_2(data[2]) |
txFrame.dataWord1 = CAN_WORD1_DATA_BYTE_4(data[4]) | CAN_WORD1_DATA_BYTE_5(data[5]) | CAN_WORD1_DATA_BYTE_6(data[6]) |

txXfer.frame = &txFrame;
FLEXCAN_TransferSendNonBlocking(CAN_IF, &flexcanHandle, &txXfer);

/* Send data through Tx Message Buffer using polling function. */
// FLEXCAN_TransferSendBlocking(CAN_IF, TX_MESSAGE_BUFFER_NUM, &txFrame);

this is my board init:

void BOARD_InitPins(void) {
CLOCK_EnableClock(kCLOCK_PortA); /* Clock Control: 0x01u */
CLOCK_EnableClock(kCLOCK_PortB); /* Clock Control: 0x01u */
CLOCK_EnableClock(kCLOCK_PortC); /* Clock Control: 0x01u */
CLOCK_EnableClock(kCLOCK_PortD); /* Clock Control: 0x01u */
CLOCK_EnableClock(kCLOCK_PortE); /* Clock Control: 0x01u */

CLOCK_EnableClock(kCLOCK_Flexcan0); /* Clock Control: 0x01u */

PORT_SetPinMux(PORTA, PIN1_IDX, kPORT_PinDisabledOrAnalog); /* PORTA1 (pin 49) is configured as ADC0_SE1 */
PORT_SetPinMux(PORTA, PIN10_IDX, kPORT_MuxAlt7); /* PORTA10 (pin 58) is configured as JTAG_TDO */
PORT_SetPinMux(PORTA, PIN3_IDX, kPORT_MuxAlt6); /* PORTA3 (pin 47) is configured as LPUART0_TX */
PORT_SetPinMux(PORTA, PIN4_IDX, kPORT_MuxAlt7); /* PORTA4 (pin 64) is configured as JTAG_TMS */
PORT_SetPinMux(PORTA, PIN5_IDX, kPORT_MuxAlt6); /* PORTA5 (pin 63) is configured as JTAG_TRST_b */
PORT_SetPinMux(PORTA, PIN6_IDX, kPORT_PinDisabledOrAnalog); /* PORTA6 (pin 38) is configured as ACMP1_IN0 */
PORT_SetPinMux(PORTA, PIN7_IDX, kPORT_PinDisabledOrAnalog); /* PORTA7 (pin 37) is configured as ADC0_SE3 */
PORT_SetPinMux(PORTB, PIN0_IDX, kPORT_MuxAlt2); /* PORTB0 (pin 34) is configured as LPUART0_RX */
PORT_SetPinMux(PORTB, PIN2_IDX, kPORT_MuxAlt3); /* PORTB2 (pin 32) is configured as LPSPI0_SCK */
PORT_SetPinMux(PORTB, PIN3_IDX, kPORT_MuxAlt2); /* PORTB3 (pin 31) is configured as FTM1_CH1 */
PORT_SetPinMux(PORTB, PIN5_IDX, kPORT_MuxAlt3); /* PORTB5 (pin 18) is configured as LPSPI0_PCS1 */
PORT_SetPinMux(PORTB, PIN6_IDX, kPORT_PinDisabledOrAnalog); /* PORTB6 (pin 12) is configured as XTAL */
PORT_SetPinMux(PORTB, PIN7_IDX, kPORT_PinDisabledOrAnalog); /* PORTB7 (pin 11) is configured as EXTAL */
PORT_SetPinMux(PORTC, PIN14_IDX, kPORT_MuxAsGpio); /* PORTC14 (pin 30) is configured as PTC14 */
PORT_SetPinMux(PORTC, PIN15_IDX, kPORT_MuxAsGpio); /* PORTC15 (pin 29) is configured as PTC15 */
PORT_SetPinMux(PORTC, PIN16_IDX, kPORT_MuxAsGpio); /* PORTC16 (pin 28) is configured as PTC16 */
PORT_SetPinMux(PORTC, PIN2_IDX, kPORT_MuxAlt3); /* PORTC2 (pin 21) is configured as CAN0_RX */
PORT_SetPinMux(PORTC, PIN3_IDX, kPORT_MuxAlt3); /* PORTC3 (pin 20) is configured as CAN0_TX */
PORT_SetPinMux(PORTC, PIN4_IDX, kPORT_MuxAlt7); /* PORTC4 (pin 62) is configured as JTAG_TCLK */
PORT_SetPinMux(PORTC, PIN5_IDX, kPORT_MuxAlt7); /* PORTC5 (pin 61) is configured as JTAG_TDI */
PORT_SetPinMux(PORTC, PIN6_IDX, kPORT_MuxAlt2); /* PORTC6 (pin 52) is configured as LPUART1_RX */
PORT_SetPinMux(PORTC, PIN7_IDX, kPORT_MuxAlt2); /* PORTC7 (pin 51) is configured as LPUART1_TX */
PORT_SetPinMux(PORTC, PIN8_IDX, kPORT_MuxAsGpio); /* PORTC8 (pin 36) is configured as PTC8 */
PORT_SetPinMux(PORTC, PIN9_IDX, kPORT_MuxAsGpio); /* PORTC9 (pin 35) is configured as PTC9 */
PORT_SetPinMux(PORTD, PIN1_IDX, kPORT_MuxAlt4); /* PORTD1 (pin 1) is configured as FTM2_CH1 */
PORT_SetPinMux(PORTD, PIN16_IDX, kPORT_PinDisabledOrAnalog); /* PORTD16 (pin 14) is configured as ACMP2_IN0 */
PORT_SetPinMux(PORTE, PIN1_IDX, kPORT_MuxAlt2); /* PORTE1 (pin 59) is configured as LPSPI0_SIN */
PORT_SetPinMux(PORTE, PIN11_IDX, kPORT_MuxAlt2); /* PORTE11 (pin 3) is configured as PWT_IN1 */
PORT_SetPinMux(PORTE, PIN2_IDX, kPORT_MuxAlt2); /* PORTE2 (pin 54) is configured as LPSPI0_SOUT */
PORT_SetPinMux(PORTE, PIN4_IDX, kPORT_MuxAsGpio); /* PORTE4 (pin 6) is configured as PTE4 */
PORT_SetPinMux(PORTE, PIN5_IDX, kPORT_MuxAsGpio); /* PORTE5 (pin 5) is configured as PTE5 */
PORT_SetPinMux(PORTE, PIN6_IDX, kPORT_MuxAsGpio); /* PORTE6 (pin 53) is configured as PTE6 */
PORT_SetPinMux(PORTE, PIN7_IDX, kPORT_MuxAsGpio); /* PORTE7 (pin 39) is configured as PTE7 */


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2 Replies

NXP Employee
NXP Employee

Hi Giovanni Gherardi

I have tested some examples codes in my side and they are working fine, I tested loopback_transfer and loopback example located in drivers example (SDK_2.2_TWR-KE18F\boards\twrke18f\driver_examples\flexcan\loopback_transfer\), both of these example works for me, did you modify this codes when you test them?

I was checking your code and I noticed that you have

FLEXCAN_Init(CAN_IF, &flexcanConfig, CAN_CLK_FREQ);
/* Create FlexCAN handle structure and set call back function. */
FLEXCAN_TransferCreateHandle(CAN_IF, &flexcanHandle, flexcan_callback, NULL);
/* Enable Rx Message Buffer interrupt. */

loopback transfer and loopback examples differs in the interrupts handlers, loopback transfer uses FLEXCAN_TransferCreateHandle and it uses callback, and loopback only uses interruption and define the handler. If you go inside FLEXCAN_TransferCreateHandle you will see that here they enable interruption and define the callback, so there is no need to use both, could you check this and tell me if it works.

Have a great day,

Note: If this post answers your question, please click the Correct Answer button. Thank you!

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Contributor I

Dear Jorge, yes the interrupt and callback are there because it was one of my several attempts to get it working. I still have the issue. Basically I have the can TX pin always at 0v when I try to send a frame. The rx pin is also at 0 but I think this is due to my transceiver that goes to sleep since the TX pin is not high. I cannot directly run the example since I'm using a custom made board with a ke16f256 not the ke18 evaluation board. I don't un test and if the problem is in the clock configuration or somewhere else. I'm running the micro with an external 24mhz crystal, a bus clock of 75mhz and a pull clock of 150mhz. I don't know if I have to set the flexcan clock with peripheral clock (in that case 75 or 150mhz) or with the oscillator clock (I guess 24mhz). I cannot find any other example on the internet except for the provided by the sdk. I really need help. 

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