Module embedded_hal::blocking::i2c
source · Expand description
Blocking I2C API
This API supports 7-bit and 10-bit addresses. Traits feature an AddressMode
marker type parameter. Two implementation of the AddressMode
exist:
SevenBitAddress
and TenBitAddress
.
Through this marker types it is possible to implement each address mode for
the traits independently in embedded-hal
implementations and device drivers
can depend only on the mode that they support.
Additionally, the I2C 10-bit address mode has been developed to be fully backwards compatible with the 7-bit address mode. This allows for a software-emulated 10-bit addressing implementation if the address mode is not supported by the hardware.
Since 7-bit addressing is the mode of the majority of I2C devices,
SevenBitAddress
has been set as default mode and thus can be omitted if desired.
Examples
embedded-hal
implementation for an MCU
Here is an example of an embedded-hal implementation of the Write
trait
for both modes:
/// I2C0 hardware peripheral which supports both 7-bit and 10-bit addressing.
pub struct I2c0;
impl Write<SevenBitAddress> for I2c0
{
fn write(&mut self, addr: u8, output: &[u8]) -> Result<(), Self::Error> {
// ...
}
}
impl Write<TenBitAddress> for I2c0
{
fn write(&mut self, addr: u16, output: &[u8]) -> Result<(), Self::Error> {
// ...
}
}
Device driver compatible only with 7-bit addresses
For demonstration purposes the address mode parameter has been omitted in this example.
const ADDR: u8 = 0x15;
pub struct TemperatureSensorDriver<I2C> {
i2c: I2C,
}
impl<I2C, E> TemperatureSensorDriver<I2C>
where
I2C: WriteRead<Error = E>,
{
pub fn read_temperature(&mut self) -> Result<u8, E> {
let mut temp = [0];
self.i2c
.write_read(ADDR, &[TEMP_REGISTER], &mut temp)
.and(Ok(temp[0]))
}
}
Device driver compatible only with 10-bit addresses
const ADDR: u16 = 0x158;
pub struct TemperatureSensorDriver<I2C> {
i2c: I2C,
}
impl<I2C, E> TemperatureSensorDriver<I2C>
where
I2C: WriteRead<TenBitAddress, Error = E>,
{
pub fn read_temperature(&mut self) -> Result<u8, E> {
let mut temp = [0];
self.i2c
.write_read(ADDR, &[TEMP_REGISTER], &mut temp)
.and(Ok(temp[0]))
}
}
Enums
- Transactional I2C operation.
Traits
- Address mode (7-bit / 10-bit)
- Blocking read
- Transactional I2C interface.
- Transactional I2C interface (iterator version).
- Blocking write
- Blocking write (iterator version)
- Blocking write (iterator version) + read
- Blocking write + read
Type Definitions
- 7-bit address mode type
- 10-bit address mode type