Add error check for d.bus.Tx()

Signed-off-by: deadprogram <ron@hybridgroup.com>

dht20/dht20.go

@@ -0,0 +1,144 @@
+// Package dht20 implements a driver for the DHT20 temperature and humidity sensor.
+//
+// Datasheet: https://cdn-shop.adafruit.com/product-files/5183/5193_DHT20.pdf
+
+package dht20
+
+import (
+	"errors"
+	"time"
+
+	"tinygo.org/x/drivers"
+)
+
+var (
+	errUpdateCalledTooSoon = errors.New("Update() called within 80ms is invalid")
+)
+
+// Device wraps an I2C connection to a DHT20 device.
+type Device struct {
+	bus            drivers.I2C
+	Address        uint16
+	data           [8]uint8
+	temperature    float32
+	humidity       float32
+	prevAccessTime time.Time
+}
+
+// New creates a new DHT20 connection. The I2C bus must already be
+// configured.
+//
+// This function only creates the Device object, it does not touch the device.
+func New(bus drivers.I2C) Device {
+	return Device{
+		bus:     bus,
+		Address: defaultAddress, // Using the address defined in registers.go
+	}
+}
+
+// Configure sets up the device for communication and initializes the registers if needed.
+func (d *Device) Configure() error {
+	// Get the status word
+	d.data[0] = 0x71
+	err := d.bus.Tx(d.Address, d.data[:1], d.data[:1])
+	if err != nil {
+		return err
+	}
+
+	if d.data[0] != 0x18 {
+		// Initialize registers
+		err := d.initRegisters()
+		if err != nil {
+			return err
+		}
+	}
+	// Set the previous access time to the current time
+	d.prevAccessTime = time.Now()
+	return nil
+}
+
+// initRegisters initializes the registers 0x1B, 0x1C, and 0x1E to 0x00.
+func (d *Device) initRegisters() error {
+	// Initialize register 0x1B
+	d.data[0] = 0x1B
+	d.data[1] = 0x00
+	err := d.bus.Tx(d.Address, d.data[:2], nil)
+	if err != nil {
+		return err
+	}
+
+	// Initialize register 0x1C
+	d.data[0] = 0x1C
+	d.data[1] = 0x00
+	err = d.bus.Tx(d.Address, d.data[:2], nil)
+	if err != nil {
+		return err
+	}
+
+	// Initialize register 0x1E
+	d.data[0] = 0x1E
+	d.data[1] = 0x00
+	err = d.bus.Tx(d.Address, d.data[:2], nil)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// Update reads data from the sensor and updates the temperature and humidity values.
+// Note that the values obtained by this function are from the previous call to Update.
+// If you want to use the most recent values, shorten the interval at which Update is called.
+func (d *Device) Update(which drivers.Measurement) error {
+	if which&drivers.Temperature == 0 && which&drivers.Humidity == 0 {
+		return nil
+	}
+
+	// Check if 80ms have passed since the last access
+	if time.Since(d.prevAccessTime) < 80*time.Millisecond {
+		return errUpdateCalledTooSoon
+	}
+
+	// Check the status word Bit[7]
+	d.data[0] = 0x71
+	err := d.bus.Tx(d.Address, d.data[:1], d.data[:1])
+	if err != nil {
+		return err
+	}
+	if (d.data[0] & 0x80) == 0 {
+		// Read 7 bytes of data from the sensor
+		err := d.bus.Tx(d.Address, nil, d.data[:7])
+		if err != nil {
+			return err
+		}
+		rawHumidity := uint32(d.data[1])<<12 | uint32(d.data[2])<<4 | uint32(d.data[3])>>4
+		rawTemperature := uint32(d.data[3]&0x0F)<<16 | uint32(d.data[4])<<8 | uint32(d.data[5])
+
+		// Convert raw values to human-readable values
+		d.humidity = float32(rawHumidity) / 1048576.0 * 100
+		d.temperature = float32(rawTemperature)/1048576.0*200 - 50
+
+		// Trigger the next measurement
+		d.data[0] = 0xAC
+		d.data[1] = 0x33
+		d.data[2] = 0x00
+		err = d.bus.Tx(d.Address, d.data[:3], nil)
+		if err != nil {
+			return err
+		}
+
+		// Update the previous access time to the current time
+		d.prevAccessTime = time.Now()
+	}
+	return nil
+}
+
+// Temperature returns the last measured temperature.
+func (d *Device) Temperature() float32 {
+	return d.temperature
+}
+
+// Humidity returns the last measured humidity.
+func (d *Device) Humidity() float32 {
+	return d.humidity
+}

dht20/registers.go

@@ -0,0 +1,6 @@
+package dht20
+
+// Constants/addresses used for I2C.
+
+// The I2C address which this device listens to.
+const defaultAddress = 0x38

examples/dht20/main.go

@@ -0,0 +1,36 @@
+package main
+
+import (
+	"machine"
+	"strconv"
+	"time"
+
+	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/dht20"
+)
+
+var (
+	i2c = machine.I2C0
+)
+
+func main() {
+	i2c.Configure(machine.I2CConfig{})
+	sensor := dht20.New(i2c)
+	sensor.Configure()
+
+	// Trigger the first measurement
+	sensor.Update(drivers.AllMeasurements)
+
+	for {
+		time.Sleep(1 * time.Second)
+
+		// Update sensor dasta
+		sensor.Update(drivers.AllMeasurements)
+		temp := sensor.Temperature()
+		hum := sensor.Humidity()
+
+		// Note: The sensor values are from the previous measurement (1 second ago)
+		println("Temperature:", strconv.FormatFloat(float64(temp), 'f', 2, 64), "°C")
+		println("Humidity:", strconv.FormatFloat(float64(hum), 'f', 2, 64), "%")
+	}
+}

examples/pcf8591/main.go

@@ -0,0 +1,28 @@
+// Connects to a pcf8591 ADC via I2C.
+package main
+
+import (
+	"machine"
+	"time"
+
+	"tinygo.org/x/drivers/pcf8591"
+)
+
+var (
+	i2c = machine.I2C0
+)
+
+func main() {
+	i2c.Configure(machine.I2CConfig{})
+	adc := pcf8591.New(i2c)
+	adc.Configure()
+
+	// get "CH0" aka "machine.ADC" interface to channel 0 from ADC.
+	p := adc.CH0
+
+	for {
+		val := p.Get()
+		println(val)
+		time.Sleep(50 * time.Millisecond)
+	}
+}

pcf8591/pcf8591.go

@@ -0,0 +1,84 @@
+// Package pcf8591 implements a driver for the PCF8591 Analog to Digital/Digital to Analog Converter.
+//
+// Datasheet: https://www.nxp.com/docs/en/data-sheet/PCF8591.pdf
+package pcf8591 // import "tinygo.org/x/drivers/pcf8591"
+
+import (
+	"machine"
+
+	"errors"
+
+	"tinygo.org/x/drivers"
+)
+
+// Device wraps PCF8591 ADC functions.
+type Device struct {
+	bus     drivers.I2C
+	Address uint16
+	CH0     ADCPin
+	CH1     ADCPin
+	CH2     ADCPin
+	CH3     ADCPin
+}
+
+// ADCPin is the implementation of the ADConverter interface.
+type ADCPin struct {
+	machine.Pin
+	d *Device
+}
+
+// New returns a new PCF8591 driver. Pass in a fully configured I2C bus.
+func New(b drivers.I2C) *Device {
+	d := &Device{
+		bus:     b,
+		Address: defaultAddress,
+	}
+
+	// setup all channels
+	d.CH0 = d.GetADC(0)
+	d.CH1 = d.GetADC(1)
+	d.CH2 = d.GetADC(2)
+	d.CH3 = d.GetADC(3)
+
+	return d
+}
+
+// Configure here just for interface compatibility.
+func (d *Device) Configure() {
+}
+
+// Read analog data from channel
+func (d *Device) Read(ch int) (uint16, error) {
+	if ch < 0 || ch > 3 {
+		return 0, errors.New("invalid channel for pcf8591 Read")
+	}
+
+	return d.GetADC(ch).Get(), nil
+}
+
+// GetADC returns an ADC for a specific channel.
+func (d *Device) GetADC(ch int) ADCPin {
+	return ADCPin{machine.Pin(ch), d}
+}
+
+// Get the current reading for a specific ADCPin.
+func (p ADCPin) Get() uint16 {
+	// TODO: also implement DAC
+	tx := make([]byte, 2)
+	tx[0] = byte(p.Pin)
+
+	rx := make([]byte, 2)
+
+	// The result from the measurement triggered by the first write,
+	// however, the second write is required to get the result.
+	// See section 8.4 "A/D Conversion" in the datasheet for more info
+	p.d.bus.Tx(p.d.Address, tx, rx)
+	p.d.bus.Tx(p.d.Address, tx, rx)
+
+	// scale result to 16bit value like other ADCs
+	return uint16(rx[1] << 8)
+}
+
+// Configure here just for interface compatibility.
+func (p ADCPin) Configure() {
+}

pcf8591/registers.go

@@ -0,0 +1,7 @@
+package pcf8591
+
+// PCF8591 Default Address
+const defaultAddress = 0x48
+
+// control bit for DAC
+const PCF8591_ENABLE_DAC = 0x40

smoketest.sh

@@ -99,6 +99,7 @@ tinygo build -size short -o ./build/test.hex -target=hifive1b ./examples/ssd1351
 tinygo build -size short -o ./build/test.hex -target=circuitplay-express ./examples/lis2mdl/main.go
 tinygo build -size short -o ./build/test.hex -target=arduino-nano33 ./examples/max72xx/main.go
 tinygo build -size short -o ./build/test.hex -target=feather-m0 ./examples/dht/main.go
+tinygo build -size short -o ./build/test.hex -target=feather-m0 ./examples/dht20/main.go
 # tinygo build -size short -o ./build/test.hex -target=arduino ./examples/keypad4x4/main.go
 tinygo build -size short -o ./build/test.hex -target=feather-rp2040 ./examples/pcf8523/
 tinygo build -size short -o ./build/test.hex -target=xiao ./examples/pcf8563/alarm/
@@ -106,6 +107,7 @@ tinygo build -size short -o ./build/test.hex -target=xiao ./examples/pcf8563/clk
 tinygo build -size short -o ./build/test.hex -target=xiao ./examples/pcf8563/time/
 tinygo build -size short -o ./build/test.hex -target=xiao ./examples/pcf8563/timer/
 tinygo build -size short -o ./build/test.hex -target=pico ./examples/qmi8658c/main.go
+tinygo build -size short -o ./build/test.hex -target=feather-rp2040 ./examples/pcf8591/
 tinygo build -size short -o ./build/test.hex -target=feather-m0 ./examples/ina260/main.go
 tinygo build -size short -o ./build/test.hex -target=nucleo-l432kc ./examples/aht20/main.go
 tinygo build -size short -o ./build/test.hex -target=feather-m4 ./examples/sdcard/console/