AURIX™ Forum Discussions

[ATY]

Hello Community,

I've been trying for a while to do CAN communication with a cancase using Canalyzer.

I tested the loopback with an example from infineon and it works well, then i configured the tx and rx pins with this way

#define CAN01_TXD_PIN IfxCan_TXD01_P15_2_OUT
#define CAN01_RXD_PIN IfxCan_RXD01A_P15_3_IN

const IfxCan_Can_Pins can01Pins = {
.txPin = &CAN01_TXD_PIN,
.txPinMode = IfxPort_OutputMode_pushPull,
.rxPin = &CAN01_RXD_PIN,
.rxPinMode = IfxPort_InputMode_pullUp,
.padDriver = IfxPort_PadDriver_cmosAutomotiveSpeed1
};

I only see errors: screnn attached

for information, I changed the configuration for the measurement of time quanta because it seems weird the default config:

here is my config:

.baudrate=500000,

.samplePoint = 8000,

.syncJumpWidth = 1,

.prescaler=8,

.timeSegment1 = 15,

.timeSegment2 = 4

the clock frequency of my MCMCAN cell = 80 Mhz measured in debug mode, and I have correctly configured the baudrate at 500kbits/s on the Canalyzer side could you help me please because i'm stuck on this part and i can't find any information

My first question: could you explain to me the default configuration that exists in all the examples of the MCMCAN: .baudrate=500000,

.samplePoint = 8000,

.syncJumpWidth = 3,

.prescaler=0,

.timeSegment1 = 3,

.timeSegment2 = 10

How they will generate a baudrate of 500kb/s with this configuration and also I put the project in zip if you have any ideas

thanks a lot for your help

[dw]

Please start from the demo code, and an email has been send to you for a modified.

Below settings is correct to make 500kbps baudrate.

        .baudRate                                    = {
            .baudrate      = 500000,
            .samplePoint   = 8000,
            .syncJumpWidth = 3,
            .prescaler     = 0,
            .timeSegment1  = 3,
            .timeSegment2  = 10
        },

[ATY]

Thank you for your feedback and thank you for the document .

By information, the external clock value on our electronic board didied in the test is 24 Mhz and when I changed the value in the CAN driver it worked, because the value IFX_CFG_SCU_XTAL_FREQUENCY in the driver is 20000000 hz, that's why, it didn't work.

Is there a cleaner way to change this?

Est ce qu'il y'a un moyen plus propre pour modifier ça ?

float32 IfxScuCcu_getPerPllFrequency1(void)
{
Ifx_SCU *scu = &MODULE_SCU;
float32 pllFrequency1;
float32 oscFreq;
//oscFreq = IfxScuCcu_getOscFrequency();

oscFreq = 24000000;

pllFrequency1 = (oscFreq * (scu->PERPLLCON0.B.NDIV + 1)) / ((scu->PERPLLCON0.B.PDIV + 1) * (scu->PERPLLCON1.B.K2DIV + 1));

return pllFrequency1;
}

Thank you for your help 

[dw]

Hi ATY, do you mean this issue is fixed? Please refer to below function for freq setting:

float32 IfxScuCcu_setMcanFrequency(float32 mcanFreq)

[ATY]

Hi DW,

Yes is fixed, I changed the external clock frequency and I redid the bit timing calculation using this link with the correct clock frequency and baudrate .

A question please, I'm not talking about the frequency of the MCMCAN but about the source clock (the external clock IFX_CFG_SCU_XTAL_FREQUENCY = 20MHZ) defined in the file Ifx_Cfg.h, is there a clean way to change this value?

Thank you very much dw for your help

[dw]

If you check below function, you will notice there are MACROs for OSC freqency.

IFX_INLINE float32 IfxScuCcu_getOscFrequency(void)
{
    float32 freq;

    if (SCU_SYSPLLCON0.B.INSEL == IfxScuCcu_PllInputClockSelection_fOsc1)
    {
        freq = IFXSCU_EVR_OSC_FREQUENCY;
    }
    else if (SCU_SYSPLLCON0.B.INSEL == IfxScuCcu_PllInputClockSelection_fOsc0)
    {
        freq = (float32)IFX_CFG_SCU_XTAL_FREQUENCY;
    }
    else if (SCU_SYSPLLCON0.B.INSEL == IfxScuCcu_PllInputClockSelection_fSysclk)
    {
        freq = IFX_CFG_SCU_SYSCLK_FREQUENCY;
    }
    else
    {
        /* Reserved values, this */
        freq = 0.0;
    }

    return freq;
}

[ATY]

Yes this is what I modified at the beginning but if we do the modification of the macro here, you can try and see ( IFX_CFG_SCU_XTAL_FREQUENCY = 24000000) to modify just the macro, it will generate quite a lot of compile error because it will not find the IFXSCU_CFG_PLL_STEPS_24MHZ_300MHZ in the project and I don't know how to set up this part 

[dw]

#if (IFX_CFG_SCU_XTAL_FREQUENCY == (20000000))
#define IFXSCU_CFG_XTAL_FREQ        20MHZ
#elif (IFX_CFG_SCU_XTAL_FREQUENCY == (25000000))
#define IFXSCU_CFG_XTAL_FREQ        25MHZ
#elif (IFX_CFG_SCU_XTAL_FREQUENCY == (40000000))
#define IFXSCU_CFG_XTAL_FREQ        40MHZ
#elif (IFX_CFG_SCU_XTAL_FREQUENCY == (16000000))
#define IFXSCU_CFG_XTAL_FREQ        16MHZ
#else
#error "Wrong XTAL frequency configuration! check IFX_CFG_SCU_XTAL_FREQUENCY configuration in Ifx_Cfg.h."
#error "AurixPlus Triboard supported crystal frequencies are  16MHz, 20MHz, 25MHz and 40MHz"
#endif

In the iLLD, only 4 crystal frequencies are used as above code showed.