Feature: shortcut I2C support for atmel-samd boards #841

matt-land · 2018-05-15T17:58:35Z

Feature: Add default I2C buses to boards
Following a maintainer discussion in Oct '17, there was a desire to have a standardized way to initialize I2C devices when using micropython.

This PR implements a standard way to initialize I2C. It does not remove any existing methods that perform the same.

import board
my_i2c = board.I2C()

The defaults are assigned following the SDA/SCL definitions of the ~~'Pinout' section in /ports/amtel-sand/boards/README.rst (when available) and best effort otherwise.~~ pins.h file of each board. A few of the boards do not have MP_QSTR_SDA/MP_QSTR_SCL defined, so I2C support was not added.

Thanks to Scott

Suppored:

Arduino Zero
Circuitplayground Express
Feather M0 Adalogger
Feather M0 Basic
Feather M0 Express
Feather M0 RFM69
Feather M0 RFM9X
Feather M0 Supersized
Feather M4 Express
Gemma M0
Itsybitsy M0 Express
Itsybitsy M4 Express
Metro M0 Express
Metro M4 Express
Metro M4 Express Rev B
Trinket M0
Trinket M0 haxpress

Not Supported:

UGame
PirKey

jerryneedell · 2018-05-15T18:09:28Z

Just curious what functionality this is adding? Isn't I2C already supported on these boards?

rhooper · 2018-05-15T18:18:36Z

ports/atmel-samd/board_busses.c

+
+STATIC mp_obj_t board_i2c(void) {
+    #if !defined(DEFAULT_I2C_BUS_SDA) || !defined(DEFAULT_I2C_BUS_SCL)
+        mp_raise_NotImplementedError('no default bus');


This should probably be "No default I2C bus" so that it's clear what the error relates to.

done. thanks

matt-land · 2018-05-15T18:30:24Z

Implementing
#372

jerryneedell · 2018-05-15T18:36:18Z

ports/atmel-samd/board_busses.c

+
+            assert_pin_free(DEFAULT_I2C_BUS_SDA);
+            assert_pin_free(DEFAULT_I2C_BUS_SCL);
+            common_hal_busio_i2c_construct(self, DEFAULT_I2C_BUS_SCL, DEFAULT_I2C_BUS_SDA, 400000);


Is the frequency always fixed at 400000? If so, is this what is wanted? Can this be overridden somehow?

It can't be over-ridden. What do you recommend? I'm still around for sprints tomorrow.

I followed what @tannewt recommended.

I think you can set your own fequency when you explicitly create the i2c object.

ah - so this is an alternative to the way we do it now? I'm just trying to understand what is being done, not objecting to it...

The idea is to default to the board's standard I2C pins when they haven't been specified.

OK - thanks for clarifying - so if you omit SCL/SDA it will trigger this. Will it still accept the full set of keyword arguments in the current API? Sorry if I am just confused.

It gives you a board.I2C that is an instance of the default I2C bus for the board, which you can then pass to your drivers. If you need to change the pins or frequency, construct your own I2C object instead.

OK - that make sense - Thanks for explaining it.

BTW - I think this will have a conflict with PR #829 but we can work that out

deshipu · 2018-05-15T20:52:52Z

Could you please explain in the pull request message what this patch actually does? This would let us avoid confusion like the one in the recent comments.

matt-land · 2018-05-16T13:59:45Z

@deshipu yes, I've updated the PR message

tannewt

For the two boards without SCL and SDA can you still add the board global entry for I2C? That way they'll raise the NotImplementedError with the better message instead of a NameError.

jerryneedell · 2018-05-16T20:50:30Z

These failures are due to PR #829 there needs to be dummy argument for the timeout.It is ignored for busio, but needed for bitbangio.

I think it just needs

change
common_hal_busio_i2c_construct(self, DEFAULT_I2C_BUS_SCL, DEFAULT_I2C_BUS_SDA, 400000); 
to
common_hal_busio_i2c_construct(self, DEFAULT_I2C_BUS_SCL, DEFAULT_I2C_BUS_SDA, 400000, 0);

or if this will ever feed into bitbangio then use 255 as the default timeout for consistency.

…obal entry for I2C? That way they'll raise the NotImplementedError with the better message instead of a NameError.

…to feature-i2c-gemma

matt-land · 2018-05-17T00:50:24Z

How do I resolve the "Changes Requested" flag?

kattni · 2018-05-17T00:51:27Z

You resolve the issues and then the reviewer who requested the changes resolves the flag.

tannewt · 2018-05-17T00:51:33Z

@matt-land just mention me asking for a re-review. I haven't figured out what the GitHub workflow is meant to be.

stale

tannewt

Looks great! Thank you!

Matt Land added 4 commits May 15, 2018 13:15

review code

b0bacd9

support for 2

a10f04a

zero + feather logger

bd7f603

formatting

cd1f662

rhooper reviewed May 15, 2018

View reviewed changes

fix non- builds

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matt-land changed the title ~~Feature: I2C support for atmel-samd boards~~ Feature: shortcut I2C support for atmel-samd boards May 15, 2018

jerryneedell reviewed May 15, 2018

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Matt Land added 3 commits May 15, 2018 15:28

feather m0 boards

4e65752

best effort

ff6e6b5

better error message

fbb57f9

Matt Land added 2 commits May 16, 2018 15:54

used pins.c instead of README.rst

2c067ed

formatting, trailing newlines

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tannewt previously requested changes May 16, 2018

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Matt Land added 3 commits May 16, 2018 17:02

For the two boards without SCL and SDA can you still add the board gl…

e8e75c0

…obal entry for I2C? That way they'll raise the NotImplementedError with the better message instead of a NameError.

Merge branch 'master' of https://github.com/adafruit/circuitpython in…

0a185c4

…to feature-i2c-gemma

Merge branch 'master' of https://github.com/adafruit/circuitpython in…

0511bec

…to feature-i2c-gemma

matt-land mentioned this pull request May 17, 2018

Feature: 'default' SPI support for atmel-samd boards #844

Merged

tannewt approved these changes May 17, 2018

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tannewt merged commit 91db71e into adafruit:master May 17, 2018

dhalbert mentioned this pull request May 23, 2018

Add default buses to board #372

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Feature: shortcut I2C support for atmel-samd boards #841

Feature: shortcut I2C support for atmel-samd boards #841

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Feature: shortcut I2C support for atmel-samd boards #841

Feature: shortcut I2C support for atmel-samd boards #841

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