Part Number: TMS320F28075
A rather old problem could be narrowed down to a HWI (Nr. 102, which is CANB_0). The HWI suddenly disappears after a couple of days using the program. This looks like that (I/O timing analysis):
1) The HWI disappears.
2) Our problem occurs because of the missing HWI.
The CAN traffic goes on, but our node went deaf. However, the CPU is still executing our program. I managed to crack the hood open and take a look at the registers. CAN_GLB_INT_FLG is 0x00000001, which tells me that an interrupt INT0 is pending and should cause the CPU to switch context to the ISR, that should be connected to the HWI as it was for a couple of days obviously. So, next I went down the rabbit hole and checked where the interrupt signal could go missing, since I cannot see for myself what SYS/BIOS is doing.
As I understand the datasheet the pending interrupt is transferred via the PIE to the CPU like
The CANB_0 is connected to channel 7 group 9. PIEIER9.INTx7 is set to 1. PIEACK.ACK9 is set to 0. IER.INT9 is set to 1. ST1.INTM is set to 0. Is there any other place I have overlook where this could go wrong? I do not get why the HWI is not executed, because it should be. The interrupt is there.
Thanks in advance for the help!
Registers_when_HWI_s_missing.txt
