STM32G0 SYSCLK can be sourced from PLLRCLK. Given that the HSI runs at
16 MHz and the HSE range is 4-48 MHz, the PLL is the only way to reach
64 MHz. This commit adds `ClockSrc::PLL`.
The PLL sources from either HSI16 or HSE, divides it by `m`, and locks
its VCO to multiple `n`. It then divides the VCO by `r`, `p`, and `q`
to produce up to three associated clock signals:
* PLLRCLK is one of the inputs on the SYSCLK mux. This is the main
reason the user will configure the PLL, so `r` is mandatory and
the output is enabled unconditionally.
* PLLPCLK is available as a clock source for the ADC and I2S
peripherals, so `p` is optional and the output is conditional.
* PLLQCLK exists only on STM32G0B0xx, and exists only to feed the
MCO and MCO2 peripherals, so `q` is optional and the output is
conditional.
When the user specifies `ClockSrc::PLL(PllConfig)`, `rcc::init()`
calls `PllConfig::init()` which initializes the PLL per [RM0454]. It
disables the PLL, waits for it to stop, enables the source
oscillator, configures the PLL, waits for it to lock, and then
enables the appropriate outputs. `rcc::init()` then switches the
clock source to PLLRCLK.
`rcc::init()` is now also resonsible for calculating and setting flash
wait states. SYSCLCK < 24 MHz is fine in the reset state, but 24-48 MHz
requires waiting 1 cycle and 48-64 MHz requires waiting 2 cycles. (This
was likely a blocker for anyone using HSE >= 24 MHz, with or without
the PLL.) Flash accesses are now automatically slowed down as needed
before changing the clock source, and sped up as permitted after
changing the clock source. The number of flash wait states also
determines if flash prefetching will be profitable, so that is now
handled automatically too.
[RM0454]: https://www.st.com/resource/en/reference_manual/rm0454-stm32g0x0-advanced-armbased-32bit-mcus-stmicroelectronics.pdf
776: Automatically set ADC clock prescaler on v2 ADC to respect max frequency r=Dirbaio a=matoushybl
Co-authored-by: Matous Hybl <hyblmatous@gmail.com>
PLL settings remained intact because these bits are not writable when PLL is enabled,
but prescaler settings were overwritten by selecting PLL as sysclk (CFGR.SW[1:0]).
The replacement is `embassy-usb`. There's a WIP driver for stm32 USBD in #709,
there's no WIP driver for stm32 USB_OTG. This means we're left without
USB_OTG support for now.
Reason for removing is I'm going to soon remove `embassy::io`, and
USB uses it. I don't want to spend time maintaining "dead" code
that is going to be removed. Volunteers welcome, either to update
old USB to the new IO, or write a USB_OTG driver fo the new USB.
743: Add PLL config support for F2 r=Dirbaio a=Gekkio
- minor changes to make the F2 RCC API a bit more flexible
- low-level PLL config with assertions based on datasheet specs. It shouldn't be very difficult to later add a "reverse API" where you pass the clocks you want to a function and it generates a `PLLConfig` struct for you
- PLL API tested on my custom board with 12 MHz HSE as source for PLL to generate max clocks for SYSCLK/AHB/APB/APB1/PLL48
- the example *should* work but is untested since I don't have the Nucleo board 😞
Co-authored-by: Joonas Javanainen <joonas.javanainen@gmail.com>
SMI Ethernet PHYs all share a common base set of registers that can do
90% of all tasks. The LAN8742 driver used some vendor-specific
registers to check link negotiation status, but the need for that was
debatable, so I migrated it to a generic driver instead, anybody who
wants extra functionality can copy it and impl their own on top of it.
This makes the configuration more flexible and closer to the underlying
configuration register structure. For example, we could use HSI for the
system clock, but use HSE to output a clock with MCO.
* Add flash drivers for L0, L1, L4, WB and WL. Not tested for WB, but
should be similar to WL.
* Add embassy-boot-stm32 for bootloading on STM32.
* Add flash examples and bootloader examples
* Update stm32-data
714: add more clock options for l4 and l5 r=Dirbaio a=ant32
- added an assert so it panics if pll48div is not 48Mhz
- added MSI as a clock source for PLL
- removed hsi48 option for MCUs mentioned in l4 rcc presentation
- copied some code from l4 to l5, but don't have a way of testing it.
Co-authored-by: Philip A Reimer <antreimer@gmail.com>
715: stm32/dac: Check proper channel r=Dirbaio a=michalsrb
Small fix. Otherwise it panics when trying to use channel 1 if channel 2 does not exist.
Co-authored-by: Michal Srb <michalsrb@gmail.com>
