This is a good board to demonstrate the use of Mboot because it only has a
USB HS port exposed so the native ST DFU mode cannot be used. With Mboot
this port can be used.
The pin alternate function information is derived from ST's datasheet
https://www.st.com/resource/en/datasheet/stm32l432kc.pdf
In the datasheet, the line 2 of AF4 includes I2C2 but actually the chip
does not have I2C2 so it is removed.
The macros are MICROPY_HEAP_START and MICROPY_HEAP_END, and if not defined
by a board then the default values will be used (maximum heap from SRAM as
defined by linker symbols).
As part of this commit the SDRAM initialisation is moved to much earlier in
main() to potentially make it available to other peripherals and avoid
re-initialisation on soft-reboot. On boards with SDRAM enabled the heap
has been set to use that.
MCUs that have a PLLSAI can use it to generate a 48MHz clock for USB, SDIO
and RNG peripherals. In such cases the SYSCLK is not restricted to values
that allow the system PLL to generate 48MHz, but can be any frequency.
This patch allows such configurability for F7 MCUs, allowing the SYSCLK to
be set in 2MHz increments via machine.freq(). PLLSAI will only be enabled
if needed, and consumes about 1mA extra. This fine grained control of
frequency is useful to get accurate SPI baudrates, for example.
Works with pins declared normally in mpconfigboard.h, eg. (pin_XX), as well
as (pyb_pin_XX).
Provides new mp_hal_pin_config_alt_static(pin_obj, mode, pull, fn_type)
function declared in pin_static_af.h to allow configuring pin alternate
functions by name at compile time.
The code was dereferencing 0x800 and loading a value from there, trying to
use a literal value (not address) defined in the linker script
(_ram_fs_cache_block_size) which was 0x800.
Pins with multiple alt-funcs for the same peripheral (eg USART_CTS_NSS)
need to be split into individual alt-funcs for make-pins.py to work
correctly.
This patch changes the following:
- Split `..._CTS_NSS` into `..._CTS/..._NSS`
- Split `..._RTS_DE` into `..._RTS/..._DE`
- Split `JTDO_SWO` into `JTDO/TRACESWO` for consistency
- Fixed `TRACECK` to `TRACECLK` for consistency
This patch allows a given board to configure which pins are used for the
CAN peripherals, in a similar way to all the other bus peripherals (I2C,
UART, SPI). To enable CAN on a board the mpconfigboard.h file should
define (for example):
#define MICROPY_HW_CAN1_TX (pin_B9)
#define MICROPY_HW_CAN1_RX (pin_B8)
#define MICROPY_HW_CAN2_TX (pin_B13)
#define MICROPY_HW_CAN2_RX (pin_B12)
And the board config file should no longer define MICROPY_HW_ENABLE_CAN.
The individual union members (like SPI, I2C) are never used, only the
generic "reg" entry is. And the union names can clash with macro
definitions in the HAL so better to remove them.
