AURIX™ Forum Discussions

[Krishnay10]

HI,

Most of the times trap 4 is being generated after CAN0_IR is being read in CanInterruptTx.

The processor is TC375. Please let me know what causes this.

[MoD]

Which trap you get (TIN)?

[Krishnay10]

Data Access Synchronous Error Trap occurred is the trap that is being generated

[Krishnay10]

DSTR register shows the below error LBE

[µC_Wrangler]

Since DEADD=0x00000004, it sounds like you've got a null pointer somewhere.

[Krishnay10]

Hi, Thanks for your reply. What would cause a read from CAN0_IR0 to be interpreted as a read from 0x0000004 address? Are there registers to check to explain it

[µC_Wrangler]

Can you share a screenshot of the disassembly where the error occurred (probably pointed to by A11)?  Also include the core registers (D0...D15 and A0...A15).

[Krishnay10]

Thanks for your reply.Here is the screenshot:

[Krishnay10]

Thanks for your reply. A11 content is shown in the above screenshot when the trap occurs. Unfortunately can't add cn to watch window

Thanks

Krishna

[µC_Wrangler]

Sure looks like Cn is null.  If you need more help as to why, you'll have to show the code where Cn is set.

[µC_Wrangler]

Can you add Cn to a watch window?  I have a sneaking suspicion it's null.

When the trap occurs, what's in A11?

[dw]

Please check TIN number, i.e. a Temporal Asynchronous Error trap (TAE - Class-4, Tin-7)

When a trap occurs identification is possible via trap class and trap identification number (TIN).
TIN is written into the core register D15

[µC_Wrangler]

D15=2, which means it's a Data Synchronous Exception / DSE (see Table 8 Supported Traps in TriCore_TC162P_core_architecture_volume_1_of_2.pdf).  That makes sense because reading from a NULL pointer is not defined in the AURIX memory map, so it results in a bus error.

[Krishnay10]

Thanks for your reply.How did you gather the info of Null Pointer reading?

Thanks

Krishna

[µC_Wrangler]

Might not be 100% correct because I don't know how Cn is declared, but this is the important bit:

if( (Cn->IR & Cn->IE & kCanIR_TC) != 0UL)

movh.a a15,#0x7000
lea a15,[a15]0x2618  ; probably Cn address 0x70002618 (check map file)
ld16.a a15,[a15]     ; what Cn points to (this is probably 0)
ld16.a a15,[a15]0x04 ; Cn->IR is 4 bytes after that (0+4=4, still bus error)

[Krishnay10 · Accepted solution]

Hi, Thanks for your help. This issue have been resolved now.

Many thanks

Krishna