Allow capturing (and distinguishing) non-SOP packets as well. The
default configuration will just configure SOP packets. For ease of use
the default receive function signature is unchanged as for PD sinks
(which is likely the common usage) just SOP is enough so no need to
differentiate.
PD3.0 spec requires concurrent control of CC resistors for collision avoidance.
Needed to introduce some "ref counting" (its just a bool) for drop code.
`select(rx.receive(), tx.transmit()` had subtle interrupt enable race conditions.
Combine receiver and transmitter into one new `PdPhy` struct to disallow the
problematic pattern.
Scanning through the USB PD 2.0 specification there is no need to have RX and TX
running concurrently (after all the USB PD communication is half-duplex).
* Improved interrupt handling: Clear flags in ISR, check state change in future
* Disable pull-up/pull-down resistors and voltage monitor on drop
* nightly rustfmt
* Implemented boost mode dance (RM0440 p234-245, 6.5.1)
* Enabled boost mode in usb_serial example, tested on hardware
* Removed hard requirement of a valid 48MHz source (HSI48 is checked if
requested, PLL passed through as-is and assumed to be valid)
* Used calc_pclk to calculate APB frequencies
* Refactored 48MHz configuration code to remove unnecessary let and block
* Renamed ahb_freq to hclk for clarity and consistency
* Copied API from f.rs where applicable
* HSE and HSI independantly configurable
* Boost mode set by user rather
* Added HSE, pll1_q and pll1_p frequencies to set_clocks call
* Stubbed max module based on f.rs, needs cleanup
With the embedded-hal rc3 update I changed them to require `&mut self`, but
in retrospect I think `&self` is better, for extra flexibility.
This PR reverts the changes from the rc3 update to inherent methods.
