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package firmata
import (
// "gobot.io/x/gobot/drivers/i2c"
"gobot.io/x/gobot/platforms/firmata/client"
)
type firmataI2cConnection struct {
address int
adaptor *Adaptor
}
// NewFirmataI2cConnection creates an I2C connection to an I2C device at
// the specified address
func NewFirmataI2cConnection(adaptor *Adaptor, address int) (connection *firmataI2cConnection) {
return &firmataI2cConnection{adaptor: adaptor, address: address}
}
// Read tries to read a full buffer from the i2c device.
// Returns an empty array if the response from the board has timed out.
func (c *firmataI2cConnection) Read(b []byte) (read int, err error) {
ret := make(chan []byte)
if err = c.adaptor.Board.I2cRead(c.address, len(b)); err != nil {
return
}
c.adaptor.Board.Once(c.adaptor.Board.Event("I2cReply"), func(data interface{}) {
ret <- data.(client.I2cReply).Data
})
result := <-ret
copy(b, result)
read = len(result)
return
}
func (c *firmataI2cConnection) Write(data []byte) (written int, err error) {
var chunk []byte
for len(data) >= 16 {
chunk, data = data[:16], data[16:]
err = c.adaptor.Board.I2cWrite(c.address, chunk)
if err != nil {
return
}
written += len(chunk)
}
if len(data) > 0 {
err = c.adaptor.Board.I2cWrite(c.address, data[:])
written += len(data)
}
return
}
func (c *firmataI2cConnection) Close() error {
return nil
}
func (c *firmataI2cConnection) ReadByte() (val byte, err error) {
buf := []byte{0}
if _, err = c.Read(buf); err != nil {
return
}
val = buf[0]
return
}
func (c *firmataI2cConnection) ReadByteData(reg uint8) (val uint8, err error) {
if err = c.WriteByte(reg); err != nil {
return
}
return c.ReadByte()
}
func (c *firmataI2cConnection) ReadWordData(reg uint8) (val uint16, err error) {
if err = c.WriteByte(reg); err != nil {
return
}
buf := []byte{0, 0}
if _, err = c.Read(buf); err != nil {
return
}
low, high := buf[0], buf[1]
val = (uint16(high) << 8) | uint16(low)
return
}
func (c *firmataI2cConnection) WriteByte(val byte) (err error) {
buf := []byte{val}
_, err = c.Write(buf)
return
}
func (c *firmataI2cConnection) WriteByteData(reg uint8, val byte) (err error) {
buf := []byte{reg, val}
_, err = c.Write(buf)
return
}
func (c *firmataI2cConnection) WriteWordData(reg uint8, val uint16) (err error) {
low := uint8(val & 0xff)
high := uint8((val >> 8) & 0xff)
buf := []byte{reg, low, high}
_, err = c.Write(buf)
return
}
func (c *firmataI2cConnection) WriteBlockData(reg uint8, data []byte) (err error) {
if len(data) > 32 {
data = data[:32]
}
buf := make([]byte, len(data)+1)
copy(buf[:1], data)
buf[0] = reg
_, err = c.Write(buf)
return
}
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