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LAUNCHXL-F28P65X: MCAN Bit Timing Calculation for choosing Nominal rate as 1Mbps and Data rate as 5Mbps

Yash Bhati
Prodigy 120 points
Part Number: LAUNCHXL-F28P65X
Other Parts Discussed in Thread: SYSCONFIG

Tool/software:

Hello TI Team,

I wanted to know how to configure the Bit Timing of MCAN, as multiple parameters required for configuration, like: nomRatePrescaler, nomTimeSeg1, nomTimeSeg2, nomSyncJumpWidth similar parameters for Data bit.

I have  checked with data sheet and reference manual for any formula or  information on this, but did not found any relevant points. 

Need your help on how to change current baud rate/bit timing(Nominal 500Kbps & Data 1Mbps) to required baud rate(Nominal 1Mbps and Data 5Mbps). I am currently using the mcan example 4 and 9 for transmit and receive.

Hardware used- LAUNCHXL-F28P65x development board.

The current bit timing values for 500Kbps and 1Mbps are:

bitTimes.nomRatePrescalar =     0x3U; // Nominal Baud Rate Pre-scaler
bitTimes.nomTimeSeg1 =            0x9U; // Nominal Time segment before SP
bitTimes.nomTimeSeg2 =            0x8U; // Nominal Time segment after SP
bitTimes.nomSynchJumpWidth = 0x8U; // Nominal SJW
bitTimes.dataRatePrescalar =      0x1U; // Data Baud Rate Pre-scaler
bitTimes.dataTimeSeg1 =             0x9U; // Data Time segment before SP
bitTimes.dataTimeSeg2 =             0x8U; // Data Time segment after SP
bitTimes.dataSynchJumpWidth = 0x8U; // Data SJW

Looking forward for your response.

Regards

Yash

  • 0
    Prodigy 120 points

    I have tried configuring it the with SysConfig file by opening MCAN Bit Timing calculator, it says "Cannot find excel". 

  • 0
    Prodigy 120 points

    I have used the provided TI's MCAN_BitTimingCalculator excel file to configure the desired Bit Timing (Nominal Bit rate as 1 Mbps and Data Bit rate as 5 Mbps). Those values  then feeded to the respective parameters. Shown in below screenshot-

    After feeding these bit timing values and  watching the signals on Oscilloscope, unable to watch the data signals there. Below is the Oscilloscope screenshot attached-

    Now attaching the TI MCAN transmit example number 9(Nominal Bit rate 500Kbps and Data bit rate 1Mbps) screenshot which works fine and able to watch the data signals on oscilloscope too-

    Data visible clearly on oscilloscope-

    Regards

    Yash