Minimal NXP/Teensy support

src/machine/machine_nxpmk66f18.go

@@ -0,0 +1,56 @@
+// +build nxp,mk66f18
+
+package machine
+
+import (
+	"device/nxp"
+	"runtime/volatile"
+)
+
+const (
+	PortControlRegisterSRE = nxp.PORT_PCR0_SRE
+	PortControlRegisterDSE = nxp.PORT_PCR0_DSE
+	PortControlRegisterODE = nxp.PORT_PCR0_ODE
+)
+
+func PortControlRegisterMUX(v uint8) uint32 {
+	return (uint32(v) << nxp.PORT_PCR0_MUX_Pos) & nxp.PORT_PCR0_MUX_Msk
+}
+
+type pinRegisters struct {
+	Bit  uintptr
+	PCR  *volatile.Register32
+	PDOR *volatile.BitRegister
+	PSOR *volatile.BitRegister
+	PCOR *volatile.BitRegister
+	PTOR *volatile.BitRegister
+	PDIR *volatile.BitRegister
+	PDDR *volatile.BitRegister
+}
+
+// Configure this pin with the given configuration.
+func (p Pin) Configure(config PinConfig) {
+	switch config.Mode {
+	case PinInput:
+		panic("todo")
+
+	case PinOutput:
+		p.registers().PDDR.Set()
+		p.registers().PCR.SetBits(PortControlRegisterSRE | PortControlRegisterDSE | PortControlRegisterMUX(1))
+		p.registers().PCR.ClearBits(PortControlRegisterODE)
+	}
+}
+
+// Set changes the value of the GPIO pin. The pin must be configured as output.
+func (p Pin) Set(value bool) {
+	if value {
+		p.registers().PSOR.Set()
+	} else {
+		p.registers().PCOR.Set()
+	}
+}
+
+// Get returns the current value of a GPIO pin.
+func (p Pin) Get() bool {
+	return p.registers().PDIR.Get()
+}