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TCAN1145-Q1: Frame_OVF

Shinji Tsuji
Genius 14564 points
Part Number: TCAN1145-Q1


Tool/software:

Hi team,

I have a couple o questions for Frame_OVF below. 

1. Is the INH pin held at high level if frame_OVF occurs during sleep mode?
2: Does the chip transition from sleep mode to standby mode when frame_OVF occurs?
3: Is it possible to disable the frame error detection feature when entering sleep mode?
4: frame_OVF_enable=0 setting disables only nINT pin interrupt reporting and is an interrupt still occurring inside the IC?

regards,

  • 0
    TI__Mastermind 30640 points

    Hi Shinji,

    1. Frame overflow will wake up the device, thus it will enter standby mode and turn INH on.

    2. Yes.

    3. No it is not possible, frame detection is feature required by CAN standard.

    4. It will disable interrupt on nINT pin only, the frame overflow can still happen.

    Regards,

    Sean

  • 0 in reply to Sean Guo
    Prodigy 110 points

    Hi

    For point #1, does this also set the CANINT flag when the device wakes up because of Frame overflow. In one of my tests, I have observed both the FRAME_OVF as well as CANINT flag set to 1 when the device wakes up because of frame error counter overflow.

  • 0 in reply to Punith Chandra
    TI__Mastermind 30640 points

    Hi Punith,

    CANINT is set only by a WUP or WUF (in selective wakeup mode), and please note that this flag can be also set in standby mode. When there is a frame overflow, it will first set FRAME_OVF flag and wake up the device, then because of the frame overflow will turn off selective wakeup, any CAN frame on the bus can be a valid WUP, thus it will set CANINT flag. 

    Regards,

    Sean

  • 0 in reply to Sean Guo
    Prodigy 110 points

    Hi ,

    1. Does that mean if the device wakes up from SLEEP because of the frame error counter overflow, both these flags are set by default?

    2. Also, if the device is already wake up because of FRAME_OVF and is in STANDBY state, why does the next CAN frame is considered as WUP/UWF and set the CANINT flag.

    3. The low power receiver is ON in both SLEEP and STANDBY state as per the user manual. What would be the changes within the device when the device is already wakeup from FRAME_OVF and is in STANDBY state (INH is HIGH because of this) and then receive the CAN frame?




    Regards,

    Punith

  • 0 in reply to Punith Chandra
    TI__Mastermind 30640 points

    Hi Punith,

    1. They are not set by default, if you are still sending CAN frames after FRAME_OVF set, then you will see CANINT set.

    2. A valid WUP/WUF can always set CANINT in standby mode, to indicate a remote wakeup from CAN bus, as standby mode is also considered as low-power mode.

    3. Nothing will change here.

    Regards,

    Sean