Tuning the frequencies #142

stianvikanes · 2023-06-28T09:31:41Z

No description provided.

gauteh · 2023-06-28T13:20:18Z

sfy-buoy/sfy-artemis/src/main.rs

@@ -303,7 +303,7 @@ fn main() -> ! {

        // XXX: This needs to be adapted to frequency, and queue length. Maybe just remove when we
        // have the remaining space check? Check after Hjeltefjorden deployment.
-        const LOOP_DELAY: u32 = 14 * 40_000;
+        const LOOP_DELAY: u32 = 10 * 40_000;                     ///////////////////////


The queue length is a little more than 14. While the time it takes to fill up a 1024 elements long buffer with 26 Hz is about 40 seconds (40_000 ms). This is the output frequency from the FIR filter, which is still 26 Hz (or 52 Hz if so configured) even if you run the IMU faster. So this should stay the same.

But you can reduce it to get more debug output of course :)

Alright, I will keep it at 14 for now, then. Thanks

…ast-2000-hz

gauteh · 2023-07-07T06:31:04Z

We are using the IMU in FIFO mode. The ODR sets the general output rate if you sample the IMU manually (i.e. read the value at the sample rate). In FIFO mode, an internal buffer is filled up on the IMU. The RTC (real time clock) interrupt in sfy-artemis/src/main.rs runs the routine at a specified interval configured in the setup code in main.rs. It calls code in lib.rs and then in waves.rs that drains the FIFO. If the buffer on the artemis is full, it makes a package and queues it for transmission home and resets the artemis-buffer.

The FIFO rate is configured with the BDR (probably in addition to the ODR), but both of those should be set correctly if you change the frequency constant. But if any of those are missing from the driver you need to make sure they are available both places.

stianvikanes · 2023-07-10T08:49:55Z

417Hz is okay. I am still working on how to increase it further. Your comment above is helpful (I locate the problem), but I still have not figured out how to make it work.

stianvikanes · 2023-07-13T10:07:06Z

I thought that if I enabled compression in FIFO (increase buffer size) i'd be able to do 833Hz, but it seems like it didn't do any difference. I'll leave it here, as it might have something to it, and i am not sure if I did it correctly :)

gauteh · 2023-07-13T10:46:01Z

sfy-buoy/sfy-artemis/src/main.rs

@@ -107,7 +107,7 @@ fn main() -> ! {
    info!("Setting up IOM and RTC.");
    delay.delay_ms(1_000u32);

-    let i2c4 = i2c::I2c::new(dp.IOM4, pins.d10, pins.d9, i2c::Freq::F400kHz);
+    let i2c4 = i2c::I2c::new(dp.IOM4, pins.d10, pins.d9, i2c::Freq::F100kHz);


This decreases the communication frequency with the SD-card, should probably not be done?

I am not sure. i2c4 is the notecarrier, and it was at 100kHz originally, so i figured i would change it back since it did not make a difference

gauteh · 2023-07-13T10:48:37Z

I thought that if I enabled compression in FIFO (increase buffer size) i'd be able to do 833Hz, but it seems like it didn't do any difference. I'll leave it here, as it might have something to it, and i am not sure if I did it correctly :)

Nice :) I did not enable it since we don't react to FIFO-full events, but drain it at regular intervals. So we would risk that it works sometimes (in the lab), but not on real data with higher entropy.

It should be easier to get high sample-rate to work without storage enabled, worth trying that first!

Are you getting any errors? Or how do you recognize that it is failing?

gauteh · 2023-07-13T10:52:36Z

Maybe you need to decrease the loop-delay in the main loop. But if it turns out that the RTC interrupt is too infrequent, you may have to do FIFO draining (current RTC interrupt handler) in the main loop.

jerabaul29 · 2023-07-13T11:00:47Z

Just curious: what frequency are you running the I2C port at? If I remember correctly the default frequencies of 100 or 400kHz are too low to sustain data transfer at 833Hz. But both the Artemis and the ISM support 1MHz I2C frequency (which is what I use om the OMB). Can this come into play, or are you already using 1MHz I2C frequency?

gauteh · 2023-07-13T11:11:05Z

Just curious: what frequency are you running the I2C port at? If I remember correctly the default frequencies of 100 or 400kHz are too low to sustain data transfer at 833Hz. But both the Artemis and the ISM support 1MHz I2C frequency (which is what I use om the OMB). Can this come into play, or are you already using 1MHz I2C frequency?

Yep, I'm pretty sure it is at 1 MHz now for the IMU. I think the modem can't do more than 100 kHz or 400 kHz, the SD-card can do many MHz (12 after initialization?). I think I was wrong, the port you have configured here in this PR is for the notecard, but it should still probably not be modified.

stianvikanes · 2023-07-13T11:54:34Z

I thought that if I enabled compression in FIFO (increase buffer size) i'd be able to do 833Hz, but it seems like it didn't do any difference. I'll leave it here, as it might have something to it, and i am not sure if I did it correctly :)

Nice :) I did not enable it since we don't react to FIFO-full events, but drain it at regular intervals. So we would risk that it works sometimes (in the lab), but not on real data with higher entropy.

It should be easier to get high sample-rate to work without storage enabled, worth trying that first!

Are you getting any errors? Or how do you recognize that it is failing?

Okay, good to know!

I am currently not having storage enabled. The error that keeps appearing is the TooFewSamples:

ERROR Too few samples, IMU may be stuck: 3010
IMU ISR failed: TooFewSamples(3010), resetting IMU..

It is originating from the check_retrieve function in lib.rs, because fifo_full = true

stianvikanes · 2023-07-13T12:12:02Z

Just curious: what frequency are you running the I2C port at? If I remember correctly the default frequencies of 100 or 400kHz are too low to sustain data transfer at 833Hz. But both the Artemis and the ISM support 1MHz I2C frequency (which is what I use om the OMB). Can this come into play, or are you already using 1MHz I2C frequency?

Yep, I'm pretty sure it is at 1 MHz now for the IMU. I think the modem can't do more than 100 kHz or 400 kHz, the SD-card can do many MHz (12 after initialization?). I think I was wrong, the port you have configured here in this PR is for the notecard, but it should still probably not be modified.

Correct, it is at 1mHz for the imu. The notecard was originally at 100kHz, so I just switched it back from 400, after trying.

gauteh · 2023-07-13T12:30:35Z

That explains it 😁

…ast-2000-hz

rebase

stianvikanes · 2023-07-18T09:32:45Z

Maybe you need to decrease the loop-delay in the main loop. But if it turns out that the RTC interrupt is too infrequent, you may have to do FIFO draining (current RTC interrupt handler) in the main loop.

I think I've figured out that the problem is the interrupt handler. It can interrupt at a frequency of CentiSecond but not faster, and that is not sufficient for sampling rate faster than 417Hz.

gauteh · 2023-07-18T10:09:39Z

Ok, then we can try to drain the FIFO in the main loop? That is a big change though. tir. 18. jul. 2023, 11:32 skrev stianvikanes ***@***.***>:

…

Maybe you need to decrease the loop-delay in the main loop. But if it turns out that the RTC interrupt is too infrequent, you may have to do FIFO draining (current RTC interrupt handler) in the main loop. I think I've figured out that the problem is the interrupt handler. It can interrupt at a frequency of CentiSecond but not faster, and that is not sufficient for sampling rate faster than 417Hz. — Reply to this email directly, view it on GitHub <#142 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAAN36Z4GLIMGAN2PX7LMNLXQZJ4RANCNFSM6AAAAAAZWYWMYQ> . You are receiving this because you commented.Message ID: ***@***.***>

stianvikanes · 2023-07-18T11:50:21Z

Ok, then we can try to drain the FIFO in the main loop? That is a big change though. tir. 18. jul. 2023, 11:32 skrev stianvikanes @.>:
…
Maybe you need to decrease the loop-delay in the main loop. But if it turns out that the RTC interrupt is too infrequent, you may have to do FIFO draining (current RTC interrupt handler) in the main loop. I think I've figured out that the problem is the interrupt handler. It can interrupt at a frequency of CentiSecond but not faster, and that is not sufficient for sampling rate faster than 417Hz. — Reply to this email directly, view it on GitHub <#142 (comment)>, or unsubscribe https://github.com/notifications/unsubscribe-auth/AAAN36Z4GLIMGAN2PX7LMNLXQZJ4RANCNFSM6AAAAAAZWYWMYQ . You are receiving this because you commented.Message ID: @.>

Yes, Let us try!
Do you have any thoughts on how it would be done?

gauteh · 2023-07-18T13:57:22Z

The SHORT_LOOP_DELAY is to avoid doing too many checks, or communicating too much with the notecard since that uses more power.

You essentially have to call the contents of the RTC function in the main loop, and remove the asm::wfi and delay instructions. You can add a delay later. Alternatively we should set up another hardware connection from the IMU to the artemis and configure it to send a signal when the FIFO is 3/4 full, it would be the best solution, but I think this is too complicated to do now. You can investigate if you want. However, if you can make it work from the main loop that is anyway proof that we can later get it to work with some hardware modifications.

So you have to move most of the contents of the RTC function to the main loop, probably before the existing if-block. You could in theory simplify stuff with the queuing since it is now not on a different interrupt (which you can think of as a separate thread), but lets keep it so that we can later use the IMU interrupt.

stianvikanes · 2023-07-19T07:26:12Z

The SHORT_LOOP_DELAY is to avoid doing too many checks, or communicating too much with the notecard since that uses more power.

You essentially have to call the contents of the RTC function in the main loop, and remove the asm::wfi and delay instructions. You can add a delay later. Alternatively we should set up another hardware connection from the IMU to the artemis and configure it to send a signal when the FIFO is 3/4 full, it would be the best solution, but I think this is too complicated to do now. You can investigate if you want. However, if you can make it work from the main loop that is anyway proof that we can later get it to work with some hardware modifications.

So you have to move most of the contents of the RTC function to the main loop, probably before the existing if-block. You could in theory simplify stuff with the queuing since it is now not on a different interrupt (which you can think of as a separate thread), but lets keep it so that we can later use the IMU interrupt.

Thanks!
I will look into it and see if I can make it work.

gauteh reviewed Jun 28, 2023

View reviewed changes

stianvikanes added 4 commits June 29, 2023 14:52

Tuning the frequencies

2217578

Trying to tune the frequencies.

ca32091

Changed dependencies

ee2770b

Temporary changes

d4eb288

stianvikanes force-pushed the 134-run-imu-and-kalman-filter-at-atleast-2000-hz branch from 2da10f8 to d4eb288 Compare June 29, 2023 12:55

Merge branch 'gauteh:main' into 134-run-imu-and-kalman-filter-at-atle…

63130b6

…ast-2000-hz

Sample rate 417Hz OK

896800a

stianvikanes added 4 commits July 10, 2023 11:07

Gets less offset with higher interrupt freq.

6b041e0

increase freq

2a9b2da

feat: Enable compression in FIFO (increases FIFO-size from 3kb to 9kb)

892be93

fix: updated freq to 833hz

409ec4f

gauteh reviewed Jul 13, 2023

View reviewed changes

stianvikanes and others added 3 commits July 13, 2023 15:25

Merge branch 'gauteh:main' into 134-run-imu-and-kalman-filter-at-atle…

39f12d3

…ast-2000-hz

Trying to tune the frequencies.

2161f05

rebase

fix: my own mistakes

33a32e3

Disable: compression

c185807

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Tuning the frequencies #142

Tuning the frequencies #142

stianvikanes commented Jun 28, 2023

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Tuning the frequencies #142

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Tuning the frequencies #142

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