This ensures that stdout (println etc) keeps working in interrupts.
Generally you shouldn't print anything in an interrupt. However,
printing things for debugging is very useful and printing panic messages
can be critical when the code doesn't work for some reason.
This is only very minimal support. More support (such as tinygo flash,
or peripheral access) should be added in later commits, to keep this one
focused.
Importantly, this commit changes the LLVM repo from llvm/llvm-project to
tinygo-org/llvm-project. This provides a little bit of versioning in
case something changes in the Espressif fork. If we want to upgrade to
LLVM 11 it's easy to switch back to llvm/llvm-project until Espressif
has updated their fork.
This also fixes a bug: the Bluefruit doesn't have a low frequency
crystal. Somehow non-SoftDevice code still worked. However, the
SoftDevice won't initialize when this flag is set incorrectly.
- Fix UART & putChar
- Timer-based sleep
- Enable systick in abort
- Buffered, interrupt-based UART TX
- Use the new interrupt API and fix sleepTicks
- Make pins behave more like other boards
- Use the MCU's UART numbering
- Allow interrupts to wake the scheduler (#1214)
The `machine.Pin` type was a int8, which works fine but limits the
number of pin numbers to 127. This patch changes the type to uint8 and
changes NoPin to 0xff, which allows more pins to be used.
Some boards might not have that many pins but their internal
organization requires more pin numbers to be used (because it is
organized in pin ports and not all pins in a port have a physical
connection). Therefore the range of a int8 is too low to address these
higher pins.
This patch also has the surprising side effect of reducing binary size
in a number of cases. If there is a reduction it's usually just a few
bytes, with one outlier: the driver example amg88xx when compiled for
the pybadge board. I have not seen any increases in binary size.
There was what appears to be a race condition in the Tx function. While
it would work fine in many cases, when there were interrupts (such as
when using BLE), the function would just hang waiting for `EVENTS_READY`
to arrive.
I think what was happening was that the `spi.Bus.RXD.Get()` would start
the next transfer, which would complete (and generate an event) before
`EVENTS_READY` was reset to 0. The fix is easy: clear `EVENTS_READY`
before doing something that can trigger an event.
I believe I've seen this bug before on the PineTime but I couldn't find
the issue back then.
