MLX90393.begin() Status Problems

[danielgarratt]

Hey,

I am trying to use two MLX90393 boards vie I2C simultaneously (eventually I will need to use four). I have a script that yields what I believe to be believable measurements from both of the sensors. An issue arises though in that I print the status of both the boards on begin and more often than not they read 255 - we have yet to see both statuses return 0 at the same time and it is fairly normal for one to return 0 while the other returns 255. I do not know how much of an issue this really is since, as I mentioned, they seem to give valid measurements despite the status regularly reading failure.

What's more is that if we call the individual methods of the begin function and print the return (ie. mlx.checkStatus(mlx.reset()), mlx.setGainSel(7), etc.) those all return 0.

Here is the setup excerpt from the script:

#include <MLX90393.h>

MLX90393 mlx1;
MLX90393 mlx2;

void setup(){

  Serial.begin(9600);
  Serial.println("hello");
  
  Wire.begin();

  delay(1000);
  uint8_t status = mlx1.begin(0, 0);
  Serial.println(status);
  uint8_t status2 = mlx2.begin(1, 0);
  Serial.println(status2);
}

[tedyapo]

I don't have a pair of boards handy to test at the moment. I wonder if both boards need to be reset() before the other commands can be sent on the shared bus. I don't think there's a convenient way to test this with the current API, but if you want to try an experiment, you might grab just enough code from begin(), reset(), and send_command() to issue resets to both boards before any other calls to either. EDIT: Actually, calling begin() a second time on each board might test this. You can check if the second set of begin()'s returns an error code.

…

On Tue, Oct 30, 2018 at 7:23 PM danielgarratt ***@***.***> wrote: Hey, I am trying to use two MLX90393 boards vie I2C simultaneously (eventually I will need to use four). I have a script that yields what I believe to be believable measurements from both of the sensors. An issue arises though in that I print the status of both the boards on begin and more often than not they read 255 - we have yet to see both statuses return 0 at the same time and it is fairly normal for one to return 0 while the other returns 255. I do not know how much of an issue this really is since, as I mentioned, they seem to give valid measurements despite the status regularly reading failure. What's more is that if we call the individual methods of the begin function and print the return (ie. mlx.checkStatus(mlx.reset()), mlx.setGainSel(7), etc.) those all return 0. Here is the setup excerpt from the script: #include <MLX90393.h> MLX90393 mlx1; MLX90393 mlx2; void setup(){ Serial.begin(9600); Serial.println("hello"); Wire.begin(); delay(1000); uint8_t status = mlx1.begin(0, 0); Serial.println(status); uint8_t status2 = mlx2.begin(1, 0); Serial.println(status2); } — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#41>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ATGvQONvv83FFZxRhLX-X31gHwdpjR4wks5uqN-DgaJpZM4YDEHw> .

[danielgarratt]

Yeah, I tried calling begin() several more times and it is only on the first time that an error is returned. I am just going to write in a couple begin() codes for each board and proceed as normal from there. The measurements seem to behave as expected anyways so I don't think it is really a problem. If I figure out why an error is being returned on the first begin() I will update this issue, but for now I think it is fine.

[tedyapo]

Thanks for reporting. I guess I could add a pre_begin(A1, A0) function which would only reset the part. You'd call pre_begin() for all parts addressable on the bus, then call begin() for them. I think the net result would be the same as two rounds of calling begin(), but no calls would fail (presumably).

I'm going to leave this open while I consider the approach and round up a few boards for testing.