Trait imxrt_usbd::Peripherals

pub unsafe trait Peripherals {
    fn instance(&self) -> Instance;
}

A type that owns all USB register blocks

An implementation of Peripherals is expected to own the USB1 or USB2 registers. This includes

• USB core registers
• USB PHY registers
• USB non-core registers
• USB analog registers

When an instance of Peripherals exists, you must make sure that nothing else, other than the owner of the Peripherals object, accesses those registers.

Safety

Peripherals should only be implemented on a type that owns the various register blocks required for all USB operation. Incorrect usage, or failure to ensure exclusive ownership, could lead to data races and incorrect USB functionality.

By implementing this trait, you ensure that the Instance identifier is valid for your chip. Not all i.MX RT peripherals have a USB2 peripheral instance, so you must ensure that the implementation is correct for your chip.

Example

A safe implementation of Peripherals that works with the imxrt-ral register access layer. Assume that ral is shorthand for imxrt_ral, like

use imxrt_ral as ral;

use ral::usb;

struct Peripherals {
    _usb: ral::usb::Instance,
    _phy: ral::usbphy::Instance,
    _nc: ral::usbnc::Instance,
    _analog: ral::usb_analog::Instance,
}

impl Peripherals {
    /// Panics if the instances are already taken
    fn usb1() -> Peripherals {
        Self {
            _usb: ral::usb::USB1::take().unwrap(),
            _phy: ral::usbphy::USBPHY1::take().unwrap(),
            _nc: ral::usbnc::USBNC1::take().unwrap(),
            _analog: ral::usb_analog::USB_ANALOG::take().unwrap(),
        }
    }
}

// This implementation is safe, because a `Peripherals` object
// owns the four imxrt-ral instances, which are
// guaranteed to be singletons. Given this approach, no one else
// can safely access the USB registers.
unsafe impl imxrt_usbd::Peripherals for Peripherals {
    fn instance(&self) -> imxrt_usbd::Instance {
        imxrt_usbd::Instance::USB1
    }
}

let peripherals = Peripherals::usb1();
let bus = imxrt_usbd::full_speed::BusAdapter::new(
    peripherals,
    // Rest of setup...
);

Required methods

fn instance(&self) -> Instance

Returns the instance identifier for the core registers

Warning: some i.MX RT peripherals have only one USB peripheral, USB1. The behavior is undefined if you return Instance::USB2 on one of these systems.

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Implementors

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