Add BLE host transport selectable via DIP8 alongside UART.

Master can speak the same framed protobuf protocol over NimBLE or UART; goTool gains -ble, ble-rtt, and ble-stream timing checks for ESP-NOW coexistence.

Co-authored-by: Cursor <cursoragent@cursor.com>

goTool/host_conn.go

@@ -0,0 +1,125 @@
+package main
+
+import (
+	"fmt"
+	"time"
+
+	pb "powerpod/gotool/pb"
+	"google.golang.org/protobuf/proto"
+)
+
+// hostConn is the UART or BLE host transport used by CLI commands.
+type hostConn interface {
+	exchangePayload(payload []byte, cmdName string) ([]byte, error)
+	exchange(cmdID byte, cmdName string) ([]byte, error)
+	Close() error
+}
+
+// optional stream source (BLE only)
+type hostStreamConn interface {
+	hostConn
+	// NextStreamTick waits for a BLE_STREAM_TICK payload (type byte + protobuf).
+	NextStreamTick(timeout time.Duration) ([]byte, error)
+}
+
+func hostGetVersion(h hostConn) (*pb.VersionResponse, error) {
+	payload, err := h.exchange(byte(pb.MessageType_VERSION), "VERSION")
+	if err != nil {
+		return nil, err
+	}
+	return decodeVersionPayload(payload)
+}
+
+func hostListClients(h hostConn) ([]*pb.ClientInfo, error) {
+	payload, err := h.exchange(byte(pb.MessageType_CLIENT_INFO), "CLIENT_INFO")
+	if err != nil {
+		return nil, err
+	}
+	return decodeClientsPayload(payload)
+}
+
+func hostReadCacheStatus(h hostConn) (*pb.CacheStatusResponse, error) {
+	payload, err := h.exchange(byte(pb.MessageType_CACHE_STATUS), "CACHE_STATUS")
+	if err != nil {
+		return nil, err
+	}
+	return decodeCacheStatusPayload(payload)
+}
+
+func hostAccelStream(h hostConn, req *pb.AccelStreamRequest) (*pb.AccelStreamResponse, error) {
+	msg := &pb.UartMessage{
+		Type: pb.MessageType_ACCEL_STREAM,
+		Payload: &pb.UartMessage_AccelStreamRequest{
+			AccelStreamRequest: req,
+		},
+	}
+	body, err := proto.Marshal(msg)
+	if err != nil {
+		return nil, fmt.Errorf("encode: %w", err)
+	}
+	payload := append([]byte{byte(pb.MessageType_ACCEL_STREAM)}, body...)
+	respPayload, err := h.exchangePayload(payload, "ACCEL_STREAM")
+	if err != nil {
+		return nil, err
+	}
+	var respMsg pb.UartMessage
+	if err := proto.Unmarshal(respPayload[1:], &respMsg); err != nil {
+		return nil, fmt.Errorf("decode: %w", err)
+	}
+	r := respMsg.GetAccelStreamResponse()
+	if r == nil {
+		return nil, fmt.Errorf("missing accel_stream_response")
+	}
+	return r, nil
+}
+
+func hostEchoPing(h hostConn, clientID uint32) (*EchoPingResult, error) {
+	t0 := time.Now()
+	timestampUs := uint64(t0.UnixMicro())
+	req := &pb.EspNowEchoPingRequest{
+		ClientId:    clientID,
+		TimestampUs: timestampUs,
+	}
+	msg := &pb.UartMessage{
+		Type: pb.MessageType_ESPNOW_ECHO_PING,
+		Payload: &pb.UartMessage_EspnowEchoPingRequest{
+			EspnowEchoPingRequest: req,
+		},
+	}
+	body, err := proto.Marshal(msg)
+	if err != nil {
+		return nil, fmt.Errorf("encode: %w", err)
+	}
+	payload := append([]byte{byte(pb.MessageType_ESPNOW_ECHO_PING)}, body...)
+	respPayload, err := h.exchangePayload(payload, "ESPNOW_ECHO_PING")
+	if err != nil {
+		return nil, err
+	}
+	rttMs := float64(time.Since(t0).Microseconds()) / 1000.0
+
+	var respMsg pb.UartMessage
+	if err := proto.Unmarshal(respPayload[1:], &respMsg); err != nil {
+		return nil, fmt.Errorf("decode: %w", err)
+	}
+	r := respMsg.GetEspnowEchoPingResponse()
+	if r == nil {
+		return nil, fmt.Errorf("missing espnow_echo_ping_response")
+	}
+	if !r.GetSuccess() {
+		return &EchoPingResult{
+			Success:  false,
+			ClientID: r.GetClientId(),
+			RttMs:    rttMs,
+		}, nil
+	}
+	if r.GetTimestampUs() != timestampUs {
+		return nil, fmt.Errorf("timestamp mismatch: sent %d got %d", timestampUs, r.GetTimestampUs())
+	}
+	return &EchoPingResult{
+		Success:     true,
+		ClientID:    r.GetClientId(),
+		TimestampUs: r.GetTimestampUs(),
+		RttMs:       rttMs,
+		EspRttUs:    r.GetEspRttUs(),
+	}, nil
+}