examples/wifi: add unified example for tcpclient that compiles for all supported wifi adaptors

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

examples/wifi/tcpclient/rtl8720dn.go

@@ -0,0 +1,77 @@
+//go:build rtl8720dn
+// +build rtl8720dn
+
+package main
+
+import (
+	"device/sam"
+	"machine"
+	"runtime/interrupt"
+	"time"
+
+	"tinygo.org/x/drivers/net"
+	"tinygo.org/x/drivers/rtl8720dn"
+)
+
+var (
+	adaptor *rtl8720dn.RTL8720DN
+
+	uart UARTx
+)
+
+func initAdaptor() *rtl8720dn.RTL8720DN {
+	adaptor, err := setupRTL8720DN()
+	if err != nil {
+		return nil
+	}
+	net.UseDriver(adaptor)
+
+	return adaptor
+}
+
+func handleInterrupt(interrupt.Interrupt) {
+	// should reset IRQ
+	uart.Receive(byte((uart.Bus.DATA.Get() & 0xFF)))
+	uart.Bus.INTFLAG.SetBits(sam.SERCOM_USART_INT_INTFLAG_RXC)
+}
+
+func setupRTL8720DN() (*rtl8720dn.RTL8720DN, error) {
+	machine.RTL8720D_CHIP_PU.Configure(machine.PinConfig{Mode: machine.PinOutput})
+	machine.RTL8720D_CHIP_PU.Low()
+	time.Sleep(100 * time.Millisecond)
+	machine.RTL8720D_CHIP_PU.High()
+	time.Sleep(1000 * time.Millisecond)
+
+	uart = UARTx{
+		UART: &machine.UART{
+			Buffer: machine.NewRingBuffer(),
+			Bus:    sam.SERCOM0_USART_INT,
+			SERCOM: 0,
+		},
+	}
+
+	uart.Interrupt = interrupt.New(sam.IRQ_SERCOM0_2, handleInterrupt)
+	uart.Configure(machine.UARTConfig{TX: machine.PB24, RX: machine.PC24, BaudRate: 614400})
+
+	rtl := rtl8720dn.New(uart)
+	//rtl.Debug(debug)
+
+	_, err := rtl.Rpc_tcpip_adapter_init()
+	if err != nil {
+		return nil, err
+	}
+
+	return rtl, nil
+}
+
+type UARTx struct {
+	*machine.UART
+}
+
+func (u UARTx) Read(p []byte) (n int, err error) {
+	if u.Buffered() == 0 {
+		time.Sleep(1 * time.Millisecond)
+		return 0, nil
+	}
+	return u.UART.Read(p)
+}