C28x "zero latency interrupts" option in SYS/BIOS

Burak Kelleci

Other Parts Discussed in Thread: SYSBIOS

Hi,

I am trying to use zero latency interrupt for EPWM1_INT interrupt. Since this interrupt is located in PIE Group 3 I used the following settings in .cfg file

var Hwi = xdc.useModule('ti.sysbios.family.c28.Hwi');
Hwi.zeroLatencyIERMask = 0x0004;

I added following lines in main function before BIOS_start().

Hwi_plug(48,OffsetISR);
Hwi_enablePIEIER(3,0x0001);

Following lines are added at the end of the OffsetISR function

PieCtrlRegs.PIEACK.bit.ACK3 = 1; // Acknowledge interrupt to PIE

The code compiles without an error or warning. I run it on ezDsp28335 board PIE registers are

PIEIER3= 0x0001

PIEIFR3= 0x0001

However, the interrupt register in the core

IER.INT3 is zero in other words it seems INT3 is not activated.

I installed bios_setupwin32_6_34_01_14.exe but it does not help.

Can somebody send an example code for implementation of zero latency interrupts?

Regards,

Burak Kelleci

over 12 years ago

Mike Volzer over 12 years ago

Intellectual 990 points

Is the global interrupt enable register bit set for that PIE group? Both the PIEIER and the IER must be enabled. IER |= 0x4

I don't think SYS/BIOS will enable the IER for you if it is unaware of the interrupt (zero latency)

Burak Kelleci over 12 years ago in reply to Mike Volzer

Prodigy 60 points

Hi,

Thanks for the reply.

I added IER |= 0x4 after Hwi_enablePIEIER(3,0x0001);

Now it gives me the following error when I run it

gged interrupt flagged: intr# 19
xdc.runtime.Error.raise: terminating execution

Regards,

Burak Kelleci

Mike Volzer over 12 years ago in reply to Burak Kelleci

Intellectual 990 points

So now it seems you have some other problem. Interrupt 19 is going off which in the Piccolo parts is an Illegal operation interrupt. You might be able to reference this post for information on how to debug xdc runtime errors. Getting the stack call trace would most likely point you in the direction you need to go.

Edit: Note that if timing is an issue you may want to read through this post which gives some good insight on how to speed things up with zero latency interrupts.

Steve Runion over 12 years ago in reply to Mike Volzer

Intellectual 960 points

Minor detail that can get you. Make sure you have "interrupt" in front of the definition of you interrupt function that will be used outside of BIOS.

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C28x "zero latency interrupts" option in SYS/BIOS