boards/esp32: adds Heltec WiFi LoRa 32 V2 board definition

[gschorcht]

Contribution description

This PR adds the board definition for Heltec WiFi LoRa 32 V2 board. Heltec WiFi LoRa 32 V2 is an ESP32 development board with 8 MB Flash that uses the EPS32 chip directly. It integrates

• a SemTech SX1276 or SX1278 for LoRaWAN communication and
• a SSD1306 128x64 OLED display connected via I2C.

Many GPIOs are broken out. Since the board is open source hardware, a number of clones are available.

Testing procedure

Application examples/lorawan can be used to test the board including the LoRaWAN functionality.

DRIVER=sx127x make BOARD=esp32-heltec-lora32-v2 -C examples/lorawan/ flash

Issues/PRs references

Depends on PR #13685

[aabadie]

Here you could also add (maybe it has other implication with esp stuff ?):

ifneq (,$(filter netdev_default,$(USEMODULE)))
  USEMODULE += sx1276
endif

[gschorcht]

Hm, ..., not sure what the most usual case is. Default network interface might be also esp_now or esp_wifi.

[benpicco]

Why is it either or?
With this you'd get both sx1276 and esp_now.

But this can be added when #12994 is merged so the user doesn't have to be careful not to forget to adding GNRC_NETIF_NUMOF=2, or else run into an assert failure when the pre-allocated netif slots run out.

[gschorcht]

@yegorich Squased.

[MrKevinWeiss]

release status ping, should I change the milestone?

[gschorcht]

@MrKevinWeiss Sorry for late answer, I'm quite busy at the moment. From my point of view, it is ready for release. I'm just waiting for a trigger to squash it.

[gschorcht]

@MrKevinWeiss Sorry for late answer, I'm quite busy at the moment. From my point of view, it is ready for release. I'm just waiting for a trigger to squash it.

[MrKevinWeiss]

Does anyone else have this board? If not I can add it to the wishlist but then I don't think it will get in to this release. Please advise otherwise I will move the milestone.

[MrKevinWeiss]

I think we can wait until next release for this one.

[fjmolinas]

@gschorcht if you can run compile_and_test_for_board and post the output it would be enough to move forward with this one.

[yegorich]

@gschorcht I think, the only thing missing is board_init() in board.h.

[gschorcht]

@gschorcht I think, the only thing missing is board_init() in board.h.

Yes, it will become a problem once I rebased it.

[gschorcht]

With the last commit, I added a small section on how to use the board's display.

[gschorcht]

May I squash this PR?

[benpicco]

More than a month has passed, I'd say it's safe to squash 😉

[gschorcht]

Squashed. But I have removed the USEMODULE += boards_common_esp32 from Makefile.dep. It will be pulled in by boards/common/esp32/Makefile.dep once PR #13685 is merged. We should wait for this cleanup.

Another question remains. @aabadie suggested to use sx1276 as netdev default.

ifneq (,$(filter netdev_default,$(USEMODULE)))
  USEMODULE += sx1276
endif

This would mean that it would pull in esp_now and sx1276. Would this be OK?

[benpicco]

You can squash again 😉

[benpicco]

Just contains definitions for common code, very straightforward.

Enabling the sx1276 radio can be done when having more than one network interface enabled by default doesn't require additional user configuration.

[gschorcht]

@benpico Thanks for reviewing and merging.