ESP32: Add AM2320 support

[thornley-david]

• This PR is for the dev-esp32 branch rather than for master.
• This PR is compliant with the other contributing guidelines as well (if not, please describe why).
• I have thoroughly tested my contribution.
• The code changes are reflected in the documentation at docs/*.

Ported almost raw from ESP8266 implementation (https://github.com/nodemcu/nodemcu-firmware/blob/release/app/modules/am2320.c).

[marcelstoer]

I'd like to land #3135 from @nwf first and then for you to rebase.

[thornley-david]

No problems, this can definitely wait.

…

On Thu, 9 Jul 2020 at 8:24 pm, Marcel Stör ***@***.***> wrote: I'd like to land #3135 <#3135> from @nwf <https://github.com/nwf> first and then for you to rebase. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#3202 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAKXTGWELLQJ7O2A7LSRD2LR2WLEJANCNFSM4OUUS2UA> .

[nwf]

Giving the C a quick once-over, there doesn't seem to be any reason that this should be a C module (or ESP32 specific) and not just some Lua code: the sensor communicates over I2C, there appear to be no timing requirements, and all math is on small integers. Maybe see #3197 or the similar Lua modules (e.g., bh1750 or ds2321 or mcp23008)?

ETA: if that's true, then there's no reason to stay blocked behind #3135.

[thornley-david]

@nwf, good point. I was just trying to reuse/migrate what was already there, however if there is a better way I am happy to rewrite it.

There are a couple of microsecond timing delays in the read negotiation, but they are likely not strict. To be honest, I am not aware if these can be transitioned to lua efficiently, and I was also not sure if the methodology I used was even correct when migrating (os_delay_us -> ets_delay_us).

I'll take a look at the sample modules in detail and disband the PR if I manage to rewrite it as a lua module.

[marcelstoer]

I'll take a look at the sample modules in detail and disband the PR if I manage to rewrite it as a lua module.

Have you come to a conclusion yet?

[marcelstoer]

In case you rebase this will have to become NODEMCU_CMODULE_AM2320.

[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. Thank you for your contributions.