hybridgroup.gobot/drivers/i2c/hmc6352_driver.go

package i2c

const hmc6352DefaultAddress = 0x21

// HMC6352Driver is a Driver for a HMC6352 digital compass
type HMC6352Driver struct {
	*Driver
}

// NewHMC6352Driver creates a new driver with specified i2c interface
// Params:
//		c Connector - the Adaptor to use with this Driver
//
// Optional params:
//		i2c.WithBus(int):	bus to use with this driver
//		i2c.WithAddress(int):	address to use with this driver
//
func NewHMC6352Driver(c Connector, options ...func(Config)) *HMC6352Driver {
	h := &HMC6352Driver{
		Driver: NewDriver(c, "HMC6352", hmc6352DefaultAddress),
	}
	h.afterStart = h.initialize

	for _, option := range options {
		option(h)
	}

	return h
}

// Heading returns the current heading
func (h *HMC6352Driver) Heading() (heading uint16, err error) {
	if _, err = h.connection.Write([]byte("A")); err != nil {
		return
	}
	buf := []byte{0, 0}
	bytesRead, err := h.connection.Read(buf)
	if err != nil {
		return
	}
	if bytesRead == 2 {
		heading = (uint16(buf[1]) + uint16(buf[0])*256) / 10
		return
	}

	err = ErrNotEnoughBytes
	return
}

func (h *HMC6352Driver) initialize() error {
	if _, err := h.connection.Write([]byte("A")); err != nil {
		return err
	}
	return nil
}