diff --git a/examples/pcf8591/main.go b/examples/pcf8591/main.go new file mode 100644 index 0000000..3994224 --- /dev/null +++ b/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) + } +} diff --git a/pcf8591/pcf8591.go b/pcf8591/pcf8591.go new file mode 100644 index 0000000..cd57dee --- /dev/null +++ b/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() { +} diff --git a/pcf8591/registers.go b/pcf8591/registers.go new file mode 100644 index 0000000..0a660cd --- /dev/null +++ b/pcf8591/registers.go @@ -0,0 +1,7 @@ +package pcf8591 + +// PCF8591 Default Address +const defaultAddress = 0x48 + +// control bit for DAC +const PCF8591_ENABLE_DAC = 0x40 diff --git a/smoketest.sh b/smoketest.sh index 569a0d8..1237d85 100755 --- a/smoketest.sh +++ b/smoketest.sh @@ -106,6 +106,7 @@ 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/