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onewire improvements

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This commit is contained in:
HattoriHanzo031
2024-10-02 20:07:17 +02:00
committed by Ron Evans
parent 07216d3051
commit 109cab4f3b
2 changed files with 19 additions and 11 deletions
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ds18b20/ds18b20.go
+2 -2
View File
@@ -19,7 +19,7 @@ type OneWireDevice interface {
Write(uint8)
Read() uint8
Select([]uint8) error
Сrc8([]uint8, int) uint8
Сrc8([]uint8) uint8
}
// Device wraps a connection to an 1-Wire devices.
@@ -69,7 +69,7 @@ func (d Device) ReadTemperatureRaw(romid []uint8) ([]uint8, error) {
for i := 0; i < 9; i++ {
spb[i] = d.owd.Read()
}
if d.owd.Сrc8(spb, 8) != spb[8] {
if d.owd.Сrc8(spb) != 0 {
return nil, errReadTemperature
}
return spb[:2:2], nil
onewire/onewire.go
+17 -9
View File
@@ -27,8 +27,9 @@ type Config struct{}
// Errors list
var (
errNoPresence = errors.New("Error: OneWire. No devices on the bus.")
errReadAddress = errors.New("Error: OneWire. Read address error: CRC mismatch.")
errNoPresence = errors.New("Error: OneWire. No devices on the bus.")
errTooManyDevices = errors.New("Error: OneWire. Too many devices on the bus.")
errReadAddress = errors.New("Error: OneWire. Read address error: CRC mismatch.")
)
// New creates a new GPIO 1-Wire connection.
@@ -46,7 +47,7 @@ func (d *Device) Configure(config Config) {}
func (d Device) Reset() error {
d.p.Configure(machine.PinConfig{Mode: machine.PinOutput})
time.Sleep(480 * time.Microsecond)
d.p.Configure(machine.PinConfig{Mode: machine.PinInput})
d.p.Configure(machine.PinConfig{Mode: machine.PinInputPullup})
time.Sleep(70 * time.Microsecond)
precence := d.p.Get()
time.Sleep(410 * time.Microsecond)
@@ -61,11 +62,11 @@ func (d Device) WriteBit(data uint8) {
d.p.Configure(machine.PinConfig{Mode: machine.PinOutput})
if data&1 == 1 { // Send '1'
time.Sleep(5 * time.Microsecond)
d.p.Configure(machine.PinConfig{Mode: machine.PinInput})
d.p.Configure(machine.PinConfig{Mode: machine.PinInputPullup})
time.Sleep(60 * time.Microsecond)
} else { // Send '0'
time.Sleep(60 * time.Microsecond)
d.p.Configure(machine.PinConfig{Mode: machine.PinInput})
d.p.Configure(machine.PinConfig{Mode: machine.PinInputPullup})
time.Sleep(5 * time.Microsecond)
}
}
@@ -82,7 +83,7 @@ func (d Device) Write(data uint8) {
func (d Device) ReadBit() (data uint8) {
d.p.Configure(machine.PinConfig{Mode: machine.PinOutput})
time.Sleep(3 * time.Microsecond)
d.p.Configure(machine.PinConfig{Mode: machine.PinInput})
d.p.Configure(machine.PinConfig{Mode: machine.PinInputPullup})
time.Sleep(8 * time.Microsecond)
if d.p.Get() {
data = 1
@@ -111,7 +112,7 @@ func (d Device) ReadAddress() ([]uint8, error) {
for i := 0; i < 8; i++ {
romid[i] = d.Read()
}
if d.Сrc8(romid, 7) != romid[7] {
if d.Сrc8(romid) != 0 {
return nil, errReadAddress
}
return romid, nil
@@ -187,15 +188,22 @@ func (d Device) Search(cmd uint8) ([][]uint8, error) {
}
d.WriteBit(bit)
}
if d.Сrc8(lastAddress) != 0 {
continue
}
lastFork = lastZero
copy(romIDs[romIndex], lastAddress)
romIndex++
if romIndex >= 32 {
return romIDs, errTooManyDevices
}
}
return romIDs[:romIndex:romIndex], nil
}
// Crc8 compute a Dallas Semiconductor 8 bit CRC.
func (d Device) Сrc8(buffer []uint8, size int) (crc uint8) {
func (_ Device) Сrc8(buffer []uint8) (crc uint8) {
// Dow-CRC using polynomial X^8 + X^5 + X^4 + X^0
// Tiny 2x16 entry CRC table created by Arjen Lentz
// See http://lentz.com.au/blog/calculating-crc-with-a-tiny-32-entry-lookup-table
@@ -205,7 +213,7 @@ func (d Device) Сrc8(buffer []uint8, size int) (crc uint8) {
0x00, 0x9D, 0x23, 0xBE, 0x46, 0xDB, 0x65, 0xF8,
0x8C, 0x11, 0xAF, 0x32, 0xCA, 0x57, 0xE9, 0x74,
}
for i := 0; i < size; i++ {
for i := 0; i < len(buffer); i++ {
crc = buffer[i] ^ crc // just re-using crc as intermediate
crc = crc8_table[crc&0x0f] ^ crc8_table[16+((crc>>4)&0x0f)]
}