TCAN1145-Q1: Datasheet related issues

Hello,

Thank you for bring these questions to E2E.

Yunmiao Li said:

  1.Which register does this reset refer to?FRAME_CNT_THRESHOLD(46H) or FRAME_CNTx(45H)?

This is referring to FRAME_CNTx(45H).

Yunmiao Li said:

  2.Is the error counter mentioned in the manual (the default threshold  is 31) the same register as the error counter (TEC/REC) that detects whether the node state has changed to error passive and bus off in ISO11898 ?

No, the error counter you are referring to is within the CAN controller. This transceiver has its own counter not referencing the error counter in the CAN controller.

Yunmiao Li said:

  3.When the chip is in sleep-mode with WUF function enabled and VCC and VIO powered off, CAN Vsup be used only to detect CAN messages in WUF wake up and pull up INH?

Yes, this is the intended use. The transceiver can detect the WUP and WUF with only VSUP present. Once the device wakes, it will transition into Standby mode and INH will go into a high state.

Yunmiao Li said:

  4.In the wake up behavior configuration of RXD, the configuration of Toggle is different from that of pull-down. There is a tmode_slp_stby(yellow mask) and a tmode1(red mask). The tmode_slp_stby can be obtained according to the table in the manual. What is the tmode1 time length? What are the factors affecting it?

This is a typo, tmode1 should also say tmode_slp_stby.

Yunmiao Li said:

  5.If RXD is configured to pull down wake-up, what is the waveform rule when it is held in stand-mode?(Flip once whenever the bus level duration exceeds twk_filter RXD?)

It will mirror the bus state if more wake requests are received, otherwise it will be in the recessive state.

Yunmiao Li said:

  However, it is also mentioned that the failure scope does not include VIO undervoltage, so in addition to VIO undervoltage, what other faults in 8 'h50~8' h54 are not included in the nINT interrupt scope? Or what register sets in 8 'h50 to 8' h54 will pull nINT down?

What this is actually saying is that if UVIO is present, nINT does not work because VIO powers the interrupt registers. Every other fault will be indicated by the nINT pin.

Regards,

Eric Hackett 

Yunmiao,

Yunmiao Li said:

So RXD waits for a tmode_slp_stby after WUP, then pulls down a tmode_slp_stby before performing the toggle activity? Is it equivalent to waiting for two tmode_slp_stbys to enter standby-mode?

This is typo on datasheet, tmode1 is actually tTOGGLE, RXD will wait for tmode_slp_stby after WUP, then perform the toggle activity.

Yunmiao Li said:

I'm not quite sure what you mean, do you mean similar logic to tcan1044a-q1?

If RXD is configured to pull down wake-up, it will just be pulled low after receiving a valid WUP, until transition to normal or listen mode.

Yunmiao Li said:

According to the reset status of registers 50 to 54H, only poweron(52H[6]) will be reset to 1b(In normal working condition, the result of all registers or operations will be 1), so does nINT perform or operations on all registers 50 to 54H except 52H[6]?

When all enabled interrupts are cleared, the nINT signal will be in a high impedance state, so an external pull-up source to VIO will be needed to use nINT. . So during the UVIO event the nINT pin will just not work, no matter what kind of interrupt it is. 

Regards,

Sean

Yunmiao,

nINT will also work if PWRON 52H[6]) set 1.

Regards,

Sean