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//go:build atmega || nrf || sam || stm32 || fe310 || k210 || rp2040
package machine
import (
"errors"
)
// TWI_FREQ is the I2C bus speed. Normally either 100 kHz, or 400 kHz for high-speed bus.
//
// Deprecated: use 100 * machine.KHz or 400 * machine.KHz instead.
const (
TWI_FREQ_100KHZ = 100000
TWI_FREQ_400KHZ = 400000
)
var (
errI2CWriteTimeout = errors.New("I2C timeout during write")
errI2CReadTimeout = errors.New("I2C timeout during read")
errI2CBusReadyTimeout = errors.New("I2C timeout on bus ready")
errI2CSignalStartTimeout = errors.New("I2C timeout on signal start")
errI2CSignalReadTimeout = errors.New("I2C timeout on signal read")
errI2CSignalStopTimeout = errors.New("I2C timeout on signal stop")
errI2CAckExpected = errors.New("I2C error: expected ACK not NACK")
errI2CBusError = errors.New("I2C bus error")
errI2COverflow = errors.New("I2C receive buffer overflow")
errI2COverread = errors.New("I2C transmit buffer overflow")
)
// I2CTargetEvent reflects events on the I2C bus
type I2CTargetEvent uint8
const (
// I2CReceive indicates target has received a message from the controller.
I2CReceive I2CTargetEvent = iota
// I2CRequest indicates the controller is expecting a message from the target.
I2CRequest
// I2CFinish indicates the controller has ended the transaction.
//
// I2C controllers can chain multiple receive/request messages without
// relinquishing the bus by doing 'restarts'. I2CFinish indicates the
// bus has been relinquished by an I2C 'stop'.
I2CFinish
)
// I2CMode determines if an I2C peripheral is in Controller or Target mode.
type I2CMode int
const (
// I2CModeController represents an I2C peripheral in controller mode.
I2CModeController I2CMode = iota
// I2CModeTarget represents an I2C peripheral in target mode.
I2CModeTarget
)
// WriteRegister transmits first the register and then the data to the
// peripheral device.
//
// Many I2C-compatible devices are organized in terms of registers. This method
// is a shortcut to easily write to such registers. Also, it only works for
// devices with 7-bit addresses, which is the vast majority.
func (i2c *I2C) WriteRegister(address uint8, register uint8, data []byte) error {
buf := make([]uint8, len(data)+1)
buf[0] = register
copy(buf[1:], data)
return i2c.Tx(uint16(address), buf, nil)
}
// ReadRegister transmits the register, restarts the connection as a read
// operation, and reads the response.
//
// Many I2C-compatible devices are organized in terms of registers. This method
// is a shortcut to easily read such registers. Also, it only works for devices
// with 7-bit addresses, which is the vast majority.
func (i2c *I2C) ReadRegister(address uint8, register uint8, data []byte) error {
return i2c.Tx(uint16(address), []byte{register}, data)
}
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