cc1310 evhSetupGpioTrigger() interrupt latency

The Sensor Controller is always on, it's the CM3 that wakes up. The latency is due to wake up of the CM3 with sync of clock domains, including 32 kHz and so on.

The sensor controller is not targeting tasks where a interrupt needs instant handling. Either all calculations has to be done in the sensor controller and/ or the sensor controller let the CM3 know that it has a value ready for processing.

Could you describe a bit closer what you want to do and we can see if it's other ways to do it?

The Sensor Controller task is rather simple. I just trigger a GPIO detection and toggle a output pin to measure the latency.

My Event Handler Code:

gpioSetOutput(AUXIO_O_DEBUG);
evhSetupGpioTrigger(0, PIN_WAKE_INDEX, 1, EVH_GPIO_TRIG_ON_EDGE);       // wait for positive wake edge
gpioClearOutput(AUXIO_O_DEBUG);

I don't wake up the CM3, but if the CM3 is in standby the latency of this interrupt increases, as you can see in my first post.

Ok, but what would the final application do (if you had short latency?)

It would decode a manchester coded serial signal. All within the sensor controller and at the end, if the package is complete, it would wake up the CM3 and pass on the data.

Do you have the format and bit/ symbol rate of the signal you want to receive?

You'll find information about the Manchester Code here: 

We would use a bit rate of 4096 Bit/s.

Sorry, what I wanted to know was the packet format, eq do you use preamble, sync etc?

I use an AMS chip. This provides a WAKE signal triggered by pattern matching and the manchester data on a DAT output. So I don't have to bother with preamble and sync.

I'm still interested to minimize the interrupt latency of the sensor controller, if possible.

Till then I keep the sensor controller task running (10 - 100ms) to receive the serial data stream, but this will delay my other tasks & drain more power.

Sorry about the delay.

We haven't looked into this type of use case in detail and have therefore not written any code. Two potential solutions:
- Use gpioGetInputValue() to poll the IO at a rate that give low enough ripple. When an edge is detected use a timer or the TDC to find the width of the pulse
- Use a IO + timer + DMA. Start/ stop timer on edge, use DMA to mode data to an array. This solution will probably give smaller code size.

Hi Armin,

I have the same problem. Can you tell me please, how did you solve it?

Thanks a lot in advance,

Rachenka