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digital.go
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/
digital.go
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package main
import (
"log"
"os"
"github.com/kidoman/embd"
_ "github.com/kidoman/embd/host/rpi"
)
// Pin definitions
const (
Mcp23017IoDirA = 0x00
Mcp23017IoDirB = 0x01
Mcp23017GpioA = 0x12
Mcp23017GpioB = 0x13
Mcp23017GppuA = 0x0C
Mcp23017GppuB = 0x0D
Mcp23017OlatA = 0x14
Mcp23017OlatB = 0x15
Mcp23008GpioA = 0x09
Mcp23008GppuA = 0x06
Mcp23008OlatA = 0x0A
)
// error log - to quit on err
var (
Error *log.Logger
)
type PiioDigital struct {
i2c embd.I2CBus
address byte
numGpios uint
direction byte
}
func (pd *PiioDigital) Init(address byte, numGpios int) {
// initialize the Error!
Error = log.New(os.Stderr,
"ERROR: ",
log.Ldate|log.Ltime|log.Lshortfile)
var err error
if numGpios < 0 || numGpios > 16 {
Error.Fatal("Number of Gpios must be between 0 and 16.")
}
pd.i2c = embd.NewI2CBus(address)
pd.address = address
pd.numGpios = uint(numGpios)
// set defaults
if numGpios <= 8 {
if err := pd.i2c.WriteByte(Mcp23017IoDirA, 0xFF); err != nil { // all inputs on port A
Error.Fatal("Unable to write byte.")
}
if pd.direction, err = pd.i2c.ReadByte(Mcp23017IoDirA); err != nil {
Error.Fatal("Unable to write byte.")
}
if err := pd.i2c.WriteByte(Mcp23008GppuA, 0x00); err != nil {
Error.Fatal("Unable to write byte.")
}
} else if numGpios > 8 {
if err := pd.i2c.WriteByte(Mcp23017IoDirA, 0XFF); err != nil { // all inputs on port A
Error.Print(err)
Error.Fatal("Unable to write byte.")
}
if err := pd.i2c.WriteByte(Mcp23017IoDirB, 0XFF); err != nil { // all inpots on port B
Error.Fatal("Unable to write byte.")
}
var t1, t2 byte
if t1, err = pd.i2c.ReadByte(Mcp23017IoDirA); err != nil {
Error.Fatal("Unable to read byte.")
}
if t2, err = pd.i2c.ReadByte(Mcp23017IoDirB); err != nil {
Error.Fatal("Unable to read byte.")
}
pd.direction = t1 | (t2 << 8)
if err := pd.i2c.WriteByte(Mcp23017GppuA, 0x00); err != nil {
Error.Fatal("Unable to write byte.")
}
if err := pd.i2c.WriteByte(Mcp23017GppuB, 0x00); err != nil {
Error.Fatal("Unable to write byte.")
}
}
}
func (pd *PiioDigital) changebit(bitmap byte, bit uint, value uint) byte {
if value == 0 {
return bitmap & ^(1 << bit)
} else if value == 1 {
return bitmap | (1 << bit)
} else {
Error.Fatalf("Value is %d, must be 0 or 1", value)
return bitmap
}
}
func (pd *PiioDigital) readAndChangePin(port byte, pin uint, value uint) byte {
var err error
if pin < 0 || pin >= pd.numGpios {
Error.Fatalf("Pin number %d is invalid, only 0-%d are valid", pin, pd.numGpios)
}
var currvalue byte
if currvalue, err = pd.i2c.ReadByte(port); err != nil {
Error.Fatal("Unable to read byte.")
}
newvalue := pd.changebit(currvalue, pin, value)
if err := pd.i2c.WriteByte(port, newvalue); err != nil {
Error.Fatal("Unable to write byte.")
}
return newvalue
}
func (pd *PiioDigital) readAndChangePinWithCurrVal(port byte, pin uint, value uint, currval byte) byte {
if pin < 0 || pin >= pd.numGpios {
Error.Fatalf("Pin number %d is invalid, only 0-%d are valid", pin, pd.numGpios)
}
newvalue := pd.changebit(currval, pin, value)
if err := pd.i2c.WriteByte(port, newvalue); err != nil {
Error.Fatal("Unable to write byte.")
}
return newvalue
}
func (pd *PiioDigital) Pullup(pin uint, value uint) byte {
if pd.numGpios <= 8 {
return pd.readAndChangePin(Mcp23008GppuA, pin, value)
} else {
// if pin < 8 {
// return -1
// }
return pd.readAndChangePin(Mcp23017GppuB, pin-8, value) << 8
}
}
// set pin to either input or output mode
func (pd *PiioDigital) Config(pin uint, mode uint) byte {
if pd.numGpios <= 8 {
pd.direction = pd.readAndChangePin(Mcp23017IoDirA, pin, mode)
} else if pd.numGpios <= 16 {
if pin < 8 {
pd.direction = pd.readAndChangePin(Mcp23017IoDirA, pin, mode)
} else {
pd.direction |= pd.readAndChangePin(Mcp23017IoDirB, pin-8, mode) << 8
}
}
return pd.direction
}
func (pd *PiioDigital) output(pin uint, value uint) byte {
var tmp byte
var err error
if pd.numGpios <= 8 {
if tmp, err = pd.i2c.ReadByte(Mcp23008OlatA); err != nil {
Error.Fatal("Unable to read byte.")
}
return pd.readAndChangePinWithCurrVal(Mcp23008GpioA, pin, value, tmp)
} else {
if pin < 8 {
if tmp, err = pd.i2c.ReadByte(Mcp23017OlatA); err != nil {
Error.Fatal("Unable to read byte.")
}
return pd.readAndChangePinWithCurrVal(Mcp23017GpioA, pin, value, tmp)
}
if tmp, err = pd.i2c.ReadByte(Mcp23017OlatB); err != nil {
Error.Fatal("Unable to read byte.")
}
return pd.readAndChangePinWithCurrVal(Mcp23017GpioB, pin-8, value, tmp) << 8
}
// self.outputvalue = self.readandchangepin(Mcp23017IoDirA, pin, value, self.outputvalue)
}
func (pd *PiioDigital) Output(pin uint, value uint) byte {
return pd.readAndChangePinWithCurrVal(Mcp23017IoDirA, pin, value, pd.output(pin, value))
}
func (pd *PiioDigital) Input(pin uint) byte {
var err error
if pin < 0 || pin >= pd.numGpios {
Error.Fatalf("Pin number %d is invalid, only 0-%d are valid", pin, pd.numGpios)
}
if pd.direction&(1<<pin) != 0 {
Error.Fatalf("Pin %d not set to input", pin)
}
var value, value2 byte
if pd.numGpios <= 8 {
if value, err = pd.i2c.ReadByte(Mcp23008GpioA); err != nil {
Error.Fatal("Unable to read byte.")
}
} else if pd.numGpios > 8 && pd.numGpios <= 16 {
if value, err = pd.i2c.ReadByte(Mcp23017GpioA); err != nil {
Error.Fatal("Unable to read byte.")
}
if value2, err = pd.i2c.ReadByte(Mcp23017GpioB); err != nil {
Error.Fatal("Unable to read byte.")
}
value = value | (value2 << 8)
}
return value & (1 << pin)
}