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package digispark
import (
"errors"
)
type digisparkI2cConnection struct {
address uint8
adaptor *Adaptor
}
// NewDigisparkI2cConnection creates an i2c connection to an i2c device at
// the specified address
func NewDigisparkI2cConnection(adaptor *Adaptor, address uint8) (connection *digisparkI2cConnection) {
return &digisparkI2cConnection{adaptor: adaptor, address: address}
}
// Init makes sure that the i2c device is already initialized
func (c *digisparkI2cConnection) Init() (err error) {
if !c.adaptor.i2c {
if err = c.adaptor.littleWire.i2cInit(); err != nil {
return
}
c.adaptor.i2c = true
}
return
}
// Test tests i2c connection with the given address
func (c *digisparkI2cConnection) Test(address uint8) error {
if !c.adaptor.i2c {
return errors.New("Digispark i2c not initialized")
}
return c.adaptor.littleWire.i2cStart(address, 0)
}
// UpdateDelay updates i2c signal delay amount; tune if neccessary to fit your requirements
func (c *digisparkI2cConnection) UpdateDelay(duration uint) error {
if !c.adaptor.i2c {
return errors.New("Digispark i2c not initialized")
}
return c.adaptor.littleWire.i2cUpdateDelay(duration)
}
// 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 *digisparkI2cConnection) Read(b []byte) (read int, err error) {
if !c.adaptor.i2c {
err = errors.New("Digispark i2c not initialized")
return
}
if err = c.adaptor.littleWire.i2cStart(c.address, 1); err != nil {
return
}
l := 8
stop := uint8(0)
for stop == 0 {
if read+l >= len(b) {
l = len(b) - read
stop = 1
}
if err = c.adaptor.littleWire.i2cRead(b[read:read+l], l, stop); err != nil {
return
}
read += l
}
return
}
func (c *digisparkI2cConnection) Write(data []byte) (written int, err error) {
if !c.adaptor.i2c {
err = errors.New("Digispark i2c not initialized")
return
}
if err = c.adaptor.littleWire.i2cStart(c.address, 0); err != nil {
return
}
l := 4
stop := uint8(0)
for stop == 0 {
if written+l >= len(data) {
l = len(data) - written
stop = 1
}
if err = c.adaptor.littleWire.i2cWrite(data[written:written+l], l, stop); err != nil {
return
}
written += l
}
return
}
func (c *digisparkI2cConnection) Close() error {
return nil
}
func (c *digisparkI2cConnection) ReadByte() (val byte, err error) {
b := make([]byte, 1)
if err = c.adaptor.littleWire.i2cRead(b, 1, 1); err != nil {
return
}
val = b[0]
return
}
func (c *digisparkI2cConnection) ReadByteData(reg uint8) (val uint8, err error) {
if err = c.WriteByte(reg); err != nil {
return
}
return c.ReadByte()
}
func (c *digisparkI2cConnection) 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 *digisparkI2cConnection) WriteByte(val byte) (err error) {
b := []byte{val}
err = c.adaptor.littleWire.i2cWrite(b, 1, 1)
return
}
func (c *digisparkI2cConnection) WriteByteData(reg uint8, val byte) (err error) {
buf := []byte{reg, val}
_, err = c.Write(buf)
return
}
func (c *digisparkI2cConnection) 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 *digisparkI2cConnection) 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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