makefiles: default-channel.inc.mk -> Supporting Sam R30 Xpro working on frequency=868MHz when sending UDP packet

[Jiawei-Lu]

Contribution description

New feature: Enable easier Channel/Page selection on the samr30-xpro.
Allows setting of the ISM 868MHz frequency band (e.g. for EU).
Use the FBAND variable like:
make BOARD=samr30-xpro FBAND=EU flash term
will change the default channel and page number into 0. This has been tested by sending UDP packets between two samr30-xpro. Check page: 387 of IEEE 802.15.4-2015 for more details about Channel/Page numbering.

Testing procedure

1.Checked UDP with:
tests/gnrc_udp by passing the FBAND variable as shown below:
make BOARD=samr30-xpro ISM=EU flash term
This has been tested by sending UPD packets between two samr30-xpro", see result shown below:


2.Also using radio checker to observe the working frequence, in my test, all packet is sending in the central frequence of 868.3MHz

Issues/PRs references

Thanks to the work of #13537, this time we don't need to change SPI_CLK into 1MHz to make it work.

[Jiawei-Lu]

Hi @jue89, Thank you for your great work #13537. This PR, I added a new parameter ISM=EU to enable Sam R30 working on 868MHz. Could you kindly help me to check my first PR?

[maribu]

One inline remark. Maybe it makes more sense to refer to the ITU region? If I remember correctly, e.g. people in Africa are using the same channel maps as the EU (as both are region 1). It would be strange for them to select EU.

Also: Most users of RIOT are ITU region 1. So why not just making this the default?

[maribu]

This is not a 802.15.4 transceiver and might be better handled separate from the others. More specifically: The channels for the cc110x driver are virtual RIOT specific numbers. What they map to is determined by the channel map. The default channel map is EU only.

[maribu]

Maybe my point is not clear. It is not possible to change the region by setting a different channel for that transceiver. Instead, one would have to fiddle with the parameters in cc110x_params.h to choose an appropriate channel map. In addition: While the chip is capable of supporting every base frequency between 300 MHz and 1GHz (with only the ISM bands in that range are tested by the vendor), the antenna circuit is specific to one ISM band. I don't know anyone with a CC110x connected to an antenna circuit suitable for 900 MHz. So no channel map for that was every tested or merged to RIOT. So someone in ITU region 2 would have to provide her/his own channel map as well; or better get that merged upstream.

[kmartinez]

this PR is only meant to affect the AT86RF212B not the cc110x driver...
You may have a point about making it ITU region 1 rather than EU... we hand't thought of that.
Default is probably stuck on USA 915 ? as its been like this for a while? however if so few people use the samr30 then lets swap it now?
Cheers!

[kmartinez]

we've worked out a sensible change - Thanks!

[jue89]

Is the 868MHz SRD band actually used in the whole ITU region 1?

[kmartinez]

looks like it: https://www.mapability.com/ei8ic/maps/regions.php

https://www.wikiwand.com/en/ITU_Region

[Jiawei-Lu]

Thanks for your suggestion! I made some changes , I hope it might be more sensible.

[kmartinez]

we decided to propose FBAND for frequency band instead to avoid confusion

[maribu]

You really should move the cc110x stuff out of this. E.g. when sticking to the FBAND approach it should be like this:

ifeq (868,$(FBAND))
  ...
else
  ...
endif

ifneq (,$(DEFAULT_CHANNEL))
  ifneq (,$(filter cc110x,$(USEMODULE)))        # radio is cc110x sub-GHz
    CFLAGS += -DCC110X_DEFAULT_CHANNEL=$(DEFAULT_CHANNEL)
  endif
endif

As said: The ISM region cannot be chosen for the CC110x transceivers, it depends on the hardware (which antenna circuit is used). Thus, it is a hardware detail that should be better configured via cc110x_params.h.

[kmartinez]

perhaps a PR for someone who can test a CC110x to make sure it tests ok?

@jue89 :
I like the suggestion to make a build-time warning if an FBAND is not set - I have no idea how many people would be impacted by a change in the default for this radio.. so this seems like a good pragmatic change

[jue89]

Thank you for your PR, @Jiawei-Lu!

To be clear: I'm just a contributor like you and not in the maintainer team of RIOT ;)

First of all, I wan't to know your motivation behind this PR. Is it the trap for young players to use the US frequencies in Europe accidentally? In that case we should rather tackle this problem than setting another default and push programmers of the US into this trap.

Maybe some descriptive warning during compilation if no channel is set explicitly? This wouldn't change the behavior of RIOT but will force everybody to consider selecting the right channel.

[Jiawei-Lu]

Thank you for your PR, @Jiawei-Lu!

To be clear: I'm just a contributor like you and not in the maintainer team of RIOT ;)

First of all, I wan't to know your motivation behind this PR. Is it the trap for young players to use the US frequencies in Europe accidentally? In that case we should rather tackle this problem than setting another default and push programmers of the US into this trap.

Maybe some descriptive warning during compilation if no channel is set explicitly? This wouldn't change the behavior of RIOT but will force everybody to consider selecting the right channel.

Thank your for your suggestion @jue89 ! I hope this PR can help more people to select right frequency band easier.

As a young player, the first question came into my mind is the frequency legitimacy. Choosing correct frequency band should the primary issue. I’d like to use 868MHz frequency band as I’m basically deploying my nodes in the U.K., thus I do need a change channel/ page number. With the increasing interest in IEEE 802.15.4 Standard, I noticed that Channel and Page number should be changed. Also there is a very detailed discussion in #12761 . Disscussion in this issue let me know how to make Smar30 working on 868MHz. However, changing the default setting is a little bit complicated. I spent long time to find this makefile that can help change the channle/page number quickly. I hope the channel/page selection can be easier for someone who want changed it so I made this PR.

Yes I think you are right I should think about that to avoid traps for user from different area. I will definitely try to improve that.

[kmartinez]

now with removed whitespace so hopefully the autotests like it better

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. If you want me to ignore this issue, please mark it with the "State: don't stale" label. Thank you for your contributions.