The regular port access is around 4 cycles, instead of the usual 2
cycles for a store instruction on Cortex-M0+. The IOBUS however is
faster, I didn't measure exactly but I guess it's 2 cycles as expected.
This fixes a bug in the WS2812 driver that only happens on samd21 chips:
https://github.com/tinygo-org/drivers/issues/540
I didn't add this method in the initial PR.
Also, I found that a few of my assumptions were incorrect. I've changed
the code that configures the pin to make input (floating and pullup)
actually work. These chips really are quite different from all the older
AVRs.
If a pointer value was xor'ed with a value other than 0, it would not
have been run at runtime but instead would fall through to the generic
integer operations. This would likely result in a "cannot convert
pointer to integer" panic.
This commit fixes this subtle case.
This is just support for the chip, no boards are currently supported.
However, you can use this target on a custom board.
Notes:
- This required a new runtime and machine implementation, because the
hardware is actually very different (and much nicer than older
AVRs!).
- I had to update gen-device-avr to support this chip. This also
affects the generated output of other AVRs, but I checked all chips
we support and there shouldn't be any backwards incompatible
changes.
- I did not implement peripherals like UART, I2C, SPI, etc because I
don't need them. That is left to do in the future.
You can flash these chips with only a UART and a 1kOhm resistor, which
is really nice (no special hardware needed). Here is the program I've
used for this purpose: https://pypi.org/project/pymcuprog/
This refactors gen-device-avr to output two different formats: one for
all the existing AVR chips (that don't really have the concept of a
peripheral, just a bunch of registers), and one for all the new chips
like the ATtiny1616 (tinyAVR 1-series and 2-series) that have
peripherals like the Cortex-M chips with type structs and instances.
I checked the generated code for all the AVR chips we have support for
(atmega1280, atmega1284p, atmega2560, atmega328p, atmega32u4, attiny85)
and while the generated Go code did change, it looks safe to me.
This is a small change that's not really important in itself, but it
avoids duplicate errors in a future commit that adds error messages to
//go:wasmimport.
This basically reverts https://github.com/tinygo-org/tinygo/pull/3357
and replaces it with a different mechanism to get to the same goal.
I do not think filtering tags like this is a good idea: it's the wrong
part of the compiler to be concerned with such tags (that part sets
tags, but doesn't modify existing tags). Instead, I've written the
//go:build lines in such a way that it has the same effect: WASI
defaults to leveldb, everything else defaults to fnv, and it's possible
to override the default using build tags.
It could be expensive to call Size() three times, and it is unnecessary.
Instead, do it only once.
This results in a very small reduction of binary size if Zero() is used.
This makes reviewing PRs a lot easier because I don't have to run this
myself :)
This only uses the drivers repo so far, which is a good starting point
but doesn't include binary size changes for WebAssembly for example. A
future change could add some real-world programs to get a better idea of
the real-world impact.
To be clear: the intention is not to just look at the number at the
bottom. It is important to look at the actual size difference to see the
overall pattern (like, the difference may be due to a few outlier).
This avoids a dependency on nrfutil. I have verified that it creates
equivalent zip files to a wasp-os DFU zip file I downloaded here:
https://github.com/wasp-os/wasp-os/releases/
I have also tested that it produces valid DFU files that can be uploaded
using the dfu.py program here to my PineTime:
3d6fd30d33
There are some minor differences in the generated file that should not
matter in practice (JSON whitespace, firmware file name, zip
compression).
* Initialize the ADC in Configure() (instead of in Get()).
* Do not set all channels to "not connected" - that's already the
reset value.
* Don't disable the ADC after use. It's not necessary to disable
(current consumption appears to remain the same whether enabled or
disabled).
* Rename pinetime-devkit0 to pinetime because the production device is
almost the same hardware (the only noticeable difference is a
different accelerometer, which isn't part of the board file).
* Remove the UART and set serial to none. The UART uses a lot of
current by default, so it seems better to disable it.
This is a breaking change, but honestly I think I'm the only one who has
ever actually used TinyGo for the PineTime and I'm fine with this
change :)
