espat: add support for esp8266/esp32 Wifi adaptor AT command set with net-compatible UDP support

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

espat/tcp.go

@@ -0,0 +1,97 @@
+package espat
+
+import (
+	"strconv"
+	"time"
+)
+
+const (
+	TCPMuxSingle   = 0
+	TCPMuxMultiple = 1
+
+	TCPTransferModeNormal      = 0
+	TCPTransferModeUnvarnished = 1
+)
+
+// ConnectTCPSocket creates a new TCP socket connection for the ESP8266/ESP32.
+// Currently only supports single connection mode.
+func (d *Device) ConnectTCPSocket(addr, port string) error {
+	protocol := "TCP"
+	val := "\"" + protocol + "\",\"" + addr + "\"," + port
+	d.Set(TCPConnect, val)
+	time.Sleep(100 * time.Millisecond)
+	d.Response()
+	return nil
+}
+
+// ConnectUDPSocket creates a new UDP connection for the ESP8266/ESP32.
+func (d *Device) ConnectUDPSocket(addr, sendport, listenport string) error {
+	protocol := "UDP"
+	val := "\"" + protocol + "\",\"" + addr + "\"," + sendport + "," + listenport + ",2"
+	d.Set(TCPConnect, val)
+	time.Sleep(pause * time.Millisecond)
+	d.Response()
+	return nil
+}
+
+// DisconnectSocket disconnects the ESP8266/ESP32 from the current TCP/UDP connection.
+func (d *Device) DisconnectSocket() error {
+	d.Execute(TCPClose)
+	time.Sleep(pause * time.Millisecond)
+	d.Response()
+	return nil
+}
+
+// SetMux sets the ESP8266/ESP32 current client TCP/UDP configuration for concurrent connections
+// either single TCPMuxSingle or multiple TCPMuxMultiple (up to 4).
+func (d *Device) SetMux(mode int) error {
+	val := strconv.Itoa(mode)
+	d.Set(TCPMultiple, val)
+	time.Sleep(pause * time.Millisecond)
+	d.Response()
+	return nil
+}
+
+// GetMux returns the ESP8266/ESP32 current client TCP/UDP configuration for concurrent connections.
+func (d *Device) GetMux() ([]byte, error) {
+	d.Query(TCPMultiple)
+	return d.Response(), nil
+}
+
+// SetTCPTransferMode sets the ESP8266/ESP32 current client TCP/UDP transfer mode.
+// Either TCPTransferModeNormal or TCPTransferModeUnvarnished.
+func (d *Device) SetTCPTransferMode(mode int) error {
+	val := strconv.Itoa(mode)
+	d.Set(TransmissionMode, val)
+	time.Sleep(pause * time.Millisecond)
+	d.Response()
+	return nil
+}
+
+// GetTCPTransferMode returns the ESP8266/ESP32 current client TCP/UDP transfer mode.
+func (d *Device) GetTCPTransferMode() []byte {
+	d.Query(TransmissionMode)
+	return d.Response()
+}
+
+// StartSocketSend gets the ESP8266/ESP32 ready to receive TCP/UDP socket data.
+func (d *Device) StartSocketSend(size int) error {
+	val := strconv.Itoa(size)
+	d.Set(TCPSend, val)
+
+	// TODO: wait until ">" is received, which indicates
+	// ready to receive data
+	d.Response()
+	return nil
+}
+
+// EndSocketSend tell the ESP8266/ESP32 the TCP/UDP socket data sending is complete,
+// and to return to command mode. This is only used in "unvarnished" raw mode.
+func (d *Device) EndSocketSend() error {
+	d.Write([]byte("+++"))
+
+	// TODO: wait until ">" is received, which indicates
+	// ready to receive data
+	d.Response()
+	return nil
+}