pub trait I2c<A: AddressMode = SevenBitAddress>: ErrorType {
// Required method
async fn transaction(
&mut self,
address: A,
operations: &mut [Operation<'_>],
) -> Result<(), Self::Error>;
// Provided methods
async fn read(
&mut self,
address: A,
read: &mut [u8],
) -> Result<(), Self::Error> { ... }
async fn write(
&mut self,
address: A,
write: &[u8],
) -> Result<(), Self::Error> { ... }
async fn write_read(
&mut self,
address: A,
write: &[u8],
read: &mut [u8],
) -> Result<(), Self::Error> { ... }
}
Expand description
Async I2c.
Required Methods§
sourceasync fn transaction(
&mut self,
address: A,
operations: &mut [Operation<'_>],
) -> Result<(), Self::Error>
async fn transaction( &mut self, address: A, operations: &mut [Operation<'_>], ) -> Result<(), Self::Error>
Execute the provided operations on the I2C bus as a single transaction.
Transaction contract:
-
Before executing the first operation an ST is sent automatically. This is followed by SAD+R/W as appropriate.
-
Data from adjacent operations of the same type are sent after each other without an SP or SR.
-
Between adjacent operations of a different type an SR and SAD+R/W is sent.
-
After executing the last operation an SP is sent automatically.
-
If the last operation is a
Read
the master does not send an acknowledge for the last byte. -
ST
= start condition -
SAD+R/W
= slave address followed by bit 1 to indicate reading or 0 to indicate writing -
SR
= repeated start condition -
SP
= stop condition
Provided Methods§
sourceasync fn read(&mut self, address: A, read: &mut [u8]) -> Result<(), Self::Error>
async fn read(&mut self, address: A, read: &mut [u8]) -> Result<(), Self::Error>
Reads enough bytes from slave with address
to fill buffer
.
§I2C Events (contract)
Master: ST SAD+R MAK MAK ... NMAK SP
Slave: SAK B0 B1 ... BN
Where
ST
= start conditionSAD+R
= slave address followed by bit 1 to indicate readingSAK
= slave acknowledgeBi
= ith byte of dataMAK
= master acknowledgeNMAK
= master no acknowledgeSP
= stop condition
sourceasync fn write(&mut self, address: A, write: &[u8]) -> Result<(), Self::Error>
async fn write(&mut self, address: A, write: &[u8]) -> Result<(), Self::Error>
Writes bytes to slave with address address
.
§I2C Events (contract)
Master: ST SAD+W B0 B1 ... BN SP
Slave: SAK SAK SAK ... SAK
Where
ST
= start conditionSAD+W
= slave address followed by bit 0 to indicate writingSAK
= slave acknowledgeBi
= ith byte of dataSP
= stop condition
sourceasync fn write_read(
&mut self,
address: A,
write: &[u8],
read: &mut [u8],
) -> Result<(), Self::Error>
async fn write_read( &mut self, address: A, write: &[u8], read: &mut [u8], ) -> Result<(), Self::Error>
Writes bytes to slave with address address
and then reads enough bytes to fill read
in a
single transaction.
§I2C Events (contract)
Master: ST SAD+W O0 O1 ... OM SR SAD+R MAK MAK ... NMAK SP
Slave: SAK SAK SAK ... SAK SAK I0 I1 ... IN
Where
ST
= start conditionSAD+W
= slave address followed by bit 0 to indicate writingSAK
= slave acknowledgeOi
= ith outgoing byte of dataSR
= repeated start conditionSAD+R
= slave address followed by bit 1 to indicate readingIi
= ith incoming byte of dataMAK
= master acknowledgeNMAK
= master no acknowledgeSP
= stop condition