- nRF51: Use `uart_conf_t` for consistency with nRF52
- nRF52832: Use UARTE (UART with EasyDMA) over UART (without DMA), as
done for all other nRF52 family members
- use `UARTE_PRESENT` to detect whether an UARTE can be used, rather
than family names
The `i2c_read_bytes()` and `i2c_write_bytes()` function return the
number of bytes written / read, instead of `0` as the API contract
says. This fixes the issue.
With only 8 possible prescalers, we can just loop over the values
and shift the clock. In addition to being much easier to read, using
shifts over divisions can be a lot faster on CPUs without hardware
division.
In addition an `assert()` is added that checks if the API contract
regarding the SPI frequency is honored. If the requested clock is too
low to be generated, we should rather have a blown assertion than
hard to trace communication errors.
Finally, the term prescaler is used instead of divider, as divider may
imply that the frequency is divided by the given value n, but
in fact is divided by 2^(n+1).
Previously, the /CS signal was performed by enabling / disabling the
SPI peripheral. This had the disadvantage that clock polarity settings
where not applied starting with `spi_acquire()`, as assumed by e.g.
the SPI SD card driver, but only just before transmitting data.
Now the SPI peripheral is enabled on `spi_acquire()` and only disabled
when calling `spi_release()`, and the `SPI_CR2_SSOE` bit in the `CR2`
register is used for hardware /CS handling (as supposed to).
This doesn't change the firmware, since for all STM32 MCUs with an
SPI driver the register setting in the mode did match the SPI mode
number by chance. But for some STM32 MCUs with no SPI driver yet
the register layout is indeed different. This will help to provide an
SPI driver for them as well.
The CR2 register was only written to if the settings differ from the
reset value. This wasn't actually a bug, since it was cleared in
`spi_release()` to the reset value again. Still, it looks like a bug,
may cause a pipeline flush due to the branch, and increased `.text`
size. So let's get rid of this.
The `SWJ_CFG` field of the `AFIO_MAPR` register is write only and values
read are undefined (random). Hence, using `AFIO->MAPR |= mask;` to
enable flags can corrupt the state of the `SWJ_CFG` (configure it to
an unintended value).
Two helper functions have been introduced:
- `afio_mapr_read()` reads the value, but sanitizes the `SWJ_CFG` field
to zero
- `afio_mapr_write()` writes the given value, but applies the `SWJ_CFG`
configured by the board before writing.
Finally, the `nucleo-f103rb` and `bluepill*`/`blackpill*` boards have
been updated to no longer specify `STM32F1_DISABLE_JTAG`, as this
is handled by the `SWJ_CFG` setting (which defaults to disabling JTAG).
`flash_<funcname>()` is implemented by `<funcname>_P()` provided by
the AVR libc on AVR targets. Previously, the preprocessor was used
to do the aliasing, but this causes issues with LLVM: The signatures of
e.g. `printf_P()` expects `const char *`, whereas flash utils expects
`FLASH_ATTR const char *`. For GCC this will just implicitly drop the
`FLASH_ATTR`, while it requires an explicit cast for LLVM.
To implement the explicit cast, `static inline` function wrappers
where used instead where possible. But for the variadic functions
(e.g. `printf(fmt, ...)`) the linker is used to provide the aliases,
as there is no way to pass the variadic functions throw in C. The
alternative would be to implement `flash_printf()` by calling
`vprintf_P()`, but that increased ROM size quite a bit.
Finally, a work around for a bug in Ubuntu's toolchain has been added:
An unused function that calls to `printf_P()`, `fprintf_P()` and
`snprintf_P()`. Since this function is garbage collected anyway, it
has no impact on the generated ELF file.
20009: cpu/native: fix bug in periph_timer r=MrKevinWeiss a=maribu
### Contribution description
While debugging https://github.com/RIOT-OS/RIOT/pull/18977#issuecomment-1764258356 it became obvious that the `periph_timer` in `native` is broken and issues early IRQs. This replaces the use of `setitimer` that cannot use a monotonic clock source with `timer_settime()`.
### Testing procedure
I have some non-publishable code that tests if the time an ISR fires in terms of `timer_read()` is no earlier than the time expected. This occasionally triggered with `master`, but I didn't see any of these issues anymore with this PR. I guess I should revive my PR to spice up the periph timer tests and add a polished version of this and let this run for an hour or two.
The tests ins `tests/periph/timer*` should still succeed on `native`. (They do for me in a container running `riot/riotbuild`).
### Issues/PRs references
Found while debugging https://github.com/RIOT-OS/RIOT/pull/18977#issuecomment-1764258356
20042: dist/tools/uf2: add target to also copy families.json file r=MrKevinWeiss a=MichelRottleuthner
### Contribution description
The updated UF2 pkg (#20035) stores the family ID in an external .json file. I overlooked that and flashing fails if this file is not present. This PR fixes it by also copying the json into the tool folder.
### Testing procedure
Check if the `feather-nrf52840-sense` can be flashed when the new UF2 pkg is cloned freshly.
### Issues/PRs references
Fixes a regression introduced with #20035
Co-authored-by: Marian Buschsieweke <marian.buschsieweke@posteo.net>
Co-authored-by: Michel Rottleuthner <michel.rottleuthner@haw-hamburg.de>
Also use `CLOCK_MONOTONIC` for the timeouts, not just for
`timer_read()`. This fixes mismatches between when a timeout
occurs and what is expected in the context of the values returned by
`timer_read()`.
