Initial support for PCA9548A 8-channel I2C-bus

examples/pca9548a/main.go

@@ -0,0 +1,67 @@
+package main
+
+import (
+	"machine"
+	"time"
+	"tinygo.org/x/drivers/bme280"
+	"tinygo.org/x/drivers/pca9548a"
+)
+
+func main() {
+	time.Sleep(5 * time.Second)
+	err := machine.I2C0.Configure(machine.I2CConfig{})
+	if err != nil {
+		panic(err.Error())
+	}
+	mux := pca9548a.New(machine.I2C0, pca9548a.Address)
+	if !mux.IsConnected() {
+		println("NO DEVICE DETECTED")
+		return
+	}
+
+	port := mux.GetPortState()
+	println("GET PORT", port)
+	mux.DisablePort()
+	mux.SetPort(0)
+	port = mux.GetPortState()
+	println("GET PORT", port)
+	mux.SetPort(1)
+	port = mux.GetPortState()
+	println("GET PORT", port)
+
+	tmpSensors := make([]bme280.Device, 2)
+
+	for i := uint8(0); i < 2; i++ {
+		mux.SetPort(i)
+		time.Sleep(10 * time.Millisecond)
+		tmpSensors[i] = bme280.New(machine.I2C0)
+		tmpSensors[i].Configure()
+
+		connected := tmpSensors[i].Connected()
+		if !connected {
+			println("\nBME280 Sensor not detected\n", i)
+		} else {
+			println("\nBME280 Sensor detected\n", i)
+		}
+	}
+	time.Sleep(10000 * time.Millisecond)
+
+	for {
+		for i := uint8(0); i < 2; i++ {
+			mux.SetPort(i)
+			t, err := tmpSensors[i].ReadTemperature()
+			if err != nil {
+				println(i, "Error reading temperature")
+			}
+			println(i, "temperature", t)
+
+			p, err := tmpSensors[i].ReadPressure()
+			if err != nil {
+				println("Error reading pressure")
+			}
+			println(i, "pressure", p)
+
+		}
+		time.Sleep(40 * time.Millisecond)
+	}
+}

pca9548a/pca9685a.go

@@ -0,0 +1,87 @@
+// Package pca9548a provides a driver for the PCA9548A 8-channel I2C-bus.
+//
+// Datasheet:
+// https://www.nxp.com/docs/en/data-sheet/PCA9548A.pdf
+package pca9548a // import "tinygo.org/x/drivers/pca9548a"
+
+import (
+	"tinygo.org/x/drivers"
+)
+
+// Device is a handle to the PCA9548A device given an address
+type Device struct {
+	addr uint8
+	bus  drivers.I2C
+	buf  [4]byte
+}
+
+// New creates a new instance of a PCA9548A device. It performs
+// no IO on the i2c bus.
+func New(bus drivers.I2C, addr uint8) Device {
+	return Device{
+		bus:  bus,
+		addr: addr,
+	}
+}
+
+// Connected returns whether a PCA9548A has been found.
+// It does a "who am I" request and checks the response.
+func (d *Device) IsConnected() bool {
+	d.SetPortState(0xA5)
+	response := d.GetPortState()
+	d.SetPortState(0x00)
+	return response == 0xA5
+}
+
+// SetPort enables the given port to send data.
+func (d *Device) SetPort(portNumber byte) {
+	portValue := uint8(0)
+	if portNumber <= 7 {
+		portValue = 1 << portNumber
+	}
+	d.bus.Tx(uint16(d.addr), []byte{portValue}, nil)
+}
+
+// GetPort gets the first port enabled.
+func (d *Device) GetPort() byte {
+	portBits := d.GetPortState()
+	for i := uint8(0); i < 8; i++ {
+		if (portBits & (1 << i)) != 0x00 {
+			return i
+		}
+	}
+	return InvalidPort
+}
+
+// SetPortState set the states of all the ports at the same time, this could cause some issues if
+// you enable two (or more) ports with the same devices at the same time.
+func (d *Device) SetPortState(portBits byte) {
+	d.bus.Tx(uint16(d.addr), []byte{portBits}, nil)
+}
+
+// GetPortState get the state of all the ports.
+func (d *Device) GetPortState() byte {
+	portBits := make([]byte, 1)
+	d.bus.Tx(uint16(d.addr), nil, portBits)
+	return portBits[0]
+}
+
+// EnablePort enables the given port without modifying any other, this could cause some issues if
+// you enable two (or more) ports with the same devices at the same time.
+func (d *Device) EnablePort(portNumber byte) {
+	if portNumber > 7 {
+		portNumber = 7
+	}
+
+	settings := d.GetPortState()
+	settings |= 1 << portNumber
+
+	d.SetPortState(settings)
+}
+
+// DisablePort disables the given port without modifying any other.
+func (d *Device) DisablePort() byte {
+	portBits := make([]byte, 1)
+	d.bus.Tx(uint16(d.addr), nil, portBits)
+	return portBits[0]
+}

pca9548a/registers.go

@@ -0,0 +1,6 @@
+package pca9548a
+
+const (
+	Address     = 0x70
+	InvalidPort = 0xff
+)

smoketest.sh

@@ -128,6 +128,7 @@ tinygo build -size short -o ./build/test.hex -target=pico ./examples/ndir/main_n
 tinygo build -size short -o ./build/test.hex -target=microbit ./examples/ndir/main_ndir.go
 tinygo build -size short -o ./build/test.hex -target=arduino-nano33 ./examples/ndir/main_ndir.go
 tinygo build -size short -o ./build/test.uf2 -target=pico ./examples/mpu9150/main.go
+tinygo build -size short -o ./build/test.uf2 -target=pico ./examples/pca9548a/main.go
 tinygo build -size short -o ./build/test.hex -target=macropad-rp2040 ./examples/sh1106/macropad_spi
 # network examples (espat)
 tinygo build -size short -o ./build/test.hex -target=challenger-rp2040 ./examples/net/ntpclient/