Why aren't some of the configuration functions for
both the compass and the ir seeker supported through
the mux?

For example...


Note that

is not in that list and there's no implementation for it for the mux elsewhere in
the file. Similar omissions exist for compass calibration functions.

Because the mux only allows reading from the sensors hooked to it but not writing to them. So unless the default mode of the sensor is what you want, good luck with changing sensor mode to non-default. I supposed that's why they call it "Sensor MUX" and not generic I2C MUX.

^-- What MHTS said.

It is a hardware limitation, no amount of programming or tweaking on my side will change that. If it's not in my driver suite, you can be pretty sure the sensor does not support it; I tend to expose all of the available functionality.

= Xander

Thanks for the response. That explains it.

We calibrated the compass by bypassing the mux.

For the IR seeker does anyone know if it defaults to the 1200hz DSP mode?

Odd though that the mux does not allow writes given that
you can get one of these

http://www.nxp.com/documents/data_sheet/PCA9548A.pdf

for about a dollar in quantity and you'll get full bi-directional
data flow. Then it's just a matter of getting the NXT brick to
understand how to select the correct port.

Given that it's possible to do generic i2c writes out a given link
it would seem that given a through hole package (i can't do surface
mount soldering), and appropriate connectors for the brick cables
it wouldn't be too difficult to build a pca9548 based mux to work with
lego sensors.

And for FTC it would be nice to have one with a voltage regulator, 7805,
to step down the voltage from the battery so it doesn't need a
separate battery pack.

But thanks Xander, I always refer to you as the nice man from Europe
who wrote all that nice software my kids are using. They laugh at me.

Yes, which also happens to be the standard frequency used by the IR beacons.


Maybe some company will come up with something like that. That wouldn't work with the analogue sensors, though.


I have a prototype HT SMUX (one of the first ones) with a nice Power Functions lead out of it, so I just hook it up to one of those battery packs.


Hah, I would probably laugh at that, too Thanks for the compliment!

= Xander

Also oddly enough we could not get the touch sensor to work through
the mux. We have the compass and IR sensor working, but add in the
touch sensor and it was a constant read of 1. The sensor works fine
directly connected to the nxt. And yes, we were using your library
functions and appropriate declarations for reading the touch sensor
through the mux vs the RobotC primitives and basic pragma setup
for reading it directly.



Please send me one.

Hrmm, are you using Driver Suite 3.2 and the 3.55 beta 2 ROBOTC? I know there were casting issues in previous versions but I thought they were fixed in beta 2.

= Xander

We are using RobotC 3.54 and whatever came before Driver Suite 3.2.

I fixed your signed/unsigned warnings in the ir-seeker file, and was going to
send you a diff when I noticed that you had released a new version and
looked at saw that you fixed them as well.

You should always use the latest of my driver suite, I only have enough time to support one version.

= Xander

Xander is good at being helpful!

[quote= "skatefriday"] Also oddly enough we could not get the touch sensor to work through
the mux. We have the compass and IR sensor working, but add in the
touch sensor and it was a constant read of 1. The sensor works fine
directly connected to the nxt. And yes, we were using your library
functions and appropriate declarations for reading the touch sensor
through the mux vs the RobotC primitives and basic pragma setup
for reading it directly.[/quote]

I had the same problem with the SMUX and the touch sensor always returning a 1.

I finally downloaded 3.55 Beta 2 with drivers 3.2.1 and i now seems to work properly.

Does anyone have any easy to use sample code for using the IR V2 on the MUX and returning the values 0 - 9?

Did you look at the hitechnic-irseeker-v2* programs? There should be a few SMUX examples in there.

= Xander

Yes I did but the programs I tried all returned raw values from the five independent channels. If you say there is sample code for returning values 0-9 Ill look harder.

Found it. Thank you.