Go 1.19 started reformatting code in a way that makes it more obvious
how it will be rendered on pkg.go.dev. It gets it almost right, but not
entirely. Therefore, I had to modify some of the comments so that they
are formatted correctly.
Do it all at once in preparation for Go 1.18 support.
To make this commit, I've simply modified the `fmt-check` Makefile
target to rewrite files instead of listing the differences. So this is a
fully mechanical change, it should not have introduced any errors.
Interrupt based time. Adjust tick cost every 1 minute and when timer-0 is reconfigured (the time precision affected when timer-0 reconfigured). Keep all time in nanoseconds.
This commit refactors PWM support in the machine package to be more
flexible. The new API can be used to produce tones at a specific
frequency and control servos in a portable way, by abstracting over
counter widths and prescalers.
All the AVRs that I've looked at had the same pin/port structure, with
the possible states being input/floating, input/pullup, low, and high
(with the same PORT/DDR registers). The main difference is the number of
available ports and pins. To reduce the amount of code and avoid
duplication (and thus errors) I decided to centralize this, following
the design used by the atmega2560 but while using a trick to save
tracking a few registers.
In the process, I noticed that the Pin.Get() function was incorrect on
the atmega2560 implementation. It is now fixed in the unified code.
This commit changes pin numbering for atmega328 based boards (Uno, Nano)
to use the standard format, where pin number is determined by the
pin/port. Previously, pin numbers were based on what the Uno uses, which
does not seem to have a clear pattern.
One difference is that counting starts at port B, as there is no port A.
So PB0 is 0, PB1 is 1… PC0 is 8.
This commit also moves PWM code to the atmega328 file, as it may not be
generic to all ATmega chips.
Not tested on actual hardware, only on simavr. The main motivation for
adding this chip is to be able to run simulated tests using a much
larger memory space (16kB RAM, 128kB flash) without jumping to the XMega
devices that may not be as well supported by LLVM.
