MC7455 AT!ANTSEL

IoT Modules MC/EM Series
1

Hi,

I’m trying to use at!antsel on my MC7455.

at!antsel=?
AT!ANTSEL= ,,,,[]
Band: 1-60
gpio1-4: GPIO Level(0 -2)
0: LOW
1: HIGH
2: Not used

Which gpio corresponds with which antenna? Is it:

gpio1 = antenna 1
gpio2 = antenna 2
gpio3 = aux / gps
gpio4 = ???

How do the gpio’s line up?

Thanks!

2

Those GPIOs don’t have any relation to onboard antenna connectors.
It’s all about signal lines on module’s system connector: pin 3 (gpio1), pin 5 (gpio2) and pin 44 (gpio3) in case of MC7455.

AT command we are talking about is to set predefined pin levels - low or high, 0 or 1 - combination for every supported band. When you switch (or modem itself switches) the currend band, you will see the corresponding levels switching on those gpioX pins.

The idea here was to switch external antennas or tune some parameters in single external antenna configurations on switching bands.

3

Thanks for the reply.

So, is there a tutorial on how to determine how to drive the GPIO’s for best performance? Would this affect speed?

I’m using external antennas. Does this set which external antenna is active on specific bands? Am I thinking about this wrong?

Thanks.

4

Yes. Let’s try again.
Those GPIOs are just three logical signal lines - 3 of 52 pins in PCIe Mini connector. Typically, they are not connected to anything from outside the modem, they are assigned to “reserved” positions in host PCIe Mini slot.

Let’s imagine that you have 5 separate external antennas - one antenna for one (from 5) single 3GPP band - and some kind of 5-way microwave switch that’s designed to select the antenna which will be connected to your modem’s antenna connector. Now you can use mentioned GPIOs to control that switch. For example, 0:0:0 control levels combination for gpio3:gpio2:gpio1 could select antenna #1, 0:0:1 combo - antenna #2, and so on.

Please note that control levels we are talking about don’t affect anything in modem and antennas themselves, they can only be used to control connections between them. Or maybe to control some internal switch in complicated multiband antenna that requires some internal tuning for every supported band.

5

Ahh… I understand.

Thank you for your patience on this one. I won’t mess with that anymore.

Is there anyway to clear the bands that I have set with antsel?

Thanks again.

6

You didn’t set any bands. You have defined some logical states for some floating, not connected to anything, pins on your modem’s connector. It doesn’t matter at all. Simply forget about them. Don’t waste your time, do something useful instead…

But if you are a perfectionist :smiley: and would like to see clear !ANTSEL list, use “2” value for all of GPIOs for specific band. See example below:

at!entercnd="A710"
OK
at!antsel?
No Setting


OK
at!antsel=3,0,0,1
OK
at!antsel?
BAND 3:  0, 0, 1, 2

Conflicts :


OK
at!antsel=3,2,2,2
OK
at!antsel?
No Setting


OK