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.
This commit lets the compiler know about interrupts and allows
optimizations to be performed based on that: interrupts are eliminated
when they appear to be unused in a program. This is done with a new
pseudo-call (runtime/interrupt.New) that is treated specially by the
compiler.
These all-caps constants aren't in the Go style, so rename it to
CPUFrequency (which is more aligned with Go style). Additionally, make
it a function so that it is possible to add support for changing the
frequency in the future.
Tested by running `make smoketest`. None of the outputs did change.
* machine/uart: add core support for multiple UARTs by allowing for multiple RingBuffers
* machine/uart: complete core support for multiple UARTs
* machine/uart: no need to store pointer to UART, better to treat like I2C and SPI
* machine/uart: increase ring buffer size to 128 bytes
* machine/uart: improve godocs comments and use comma-ok idiom for buffer Put/Get methods
