add helper telnet

.gitignore

@@ -3,3 +3,4 @@
 .vscode/c_cpp_properties.json
 .vscode/launch.json
 .vscode/ipch
+.venv/

helper/remote-serial.py

@@ -0,0 +1,125 @@
+#!/usr/bin/env python3
+"""
+Telnet-only tool to toggle DTR/RTS via ser2net admin console.
+
+New sequences (physical levels):
+ - restart:  RTS HI -> DTR LO -> DTR HI
+ - download: RTS LO -> DTR LO -> DTR HI -> RTS HI
+
+Timing parameters tunable via args (ms). Use admin host/port and connection name (con).
+Example:
+  python3 helper/remote-serial.py --host 192.168.1.100 --admin-port 7373 --con con1 --action restart -v
+"""
+import argparse
+import socket
+import errno
+import time
+import sys
+
+def send_admin_cmd(host, port, cmd, timeout=1.0, verbose=False):
+    if verbose:
+        print(f"> {cmd}")
+    try:
+        with socket.create_connection((host, port), timeout=timeout) as s:
+            s.settimeout(timeout)
+            try:
+                s.sendall(cmd.encode('ascii') + b"\n")
+            except Exception as e:
+                print(f"ERROR sending command: {e}", file=sys.stderr)
+                return None
+            # small pause to let server respond
+            time.sleep(0.05)
+            chunks = []
+            while True:
+                try:
+                    data = s.recv(4096)
+                    if not data:
+                        break
+                    chunks.append(data)
+                    # short sleep to allow more data to arrive
+                    time.sleep(0.01)
+                except socket.timeout:
+                    break
+                except OSError as e:
+                    if getattr(e, 'errno', None) == errno.EWOULDBLOCK:
+                        break
+                    break
+            resp = b"".join(chunks)
+            if resp:
+                try:
+                    txt = resp.decode(errors="ignore")
+                except Exception:
+                    txt = str(resp)
+                if verbose:
+                    print(txt.strip())
+                return txt
+            return ""
+    except Exception as e:
+        print(f"ERROR: cannot connect to {host}:{port} -> {e}", file=sys.stderr)
+        return None
+
+def set_port_control(host, admin_port, con, line, hi_or_lo, timeout, verbose):
+    # hi_or_lo must be 'HI' or 'LO'
+    cmd = f"setportcontrol {con} {line}{hi_or_lo}"
+    return send_admin_cmd(host, admin_port, cmd, timeout=timeout, verbose=verbose)
+
+def run_sequence(host, admin_port, con, seq, timeout, verbose):
+    # seq: list of (line, state, sleep_seconds)
+    for line, state, sleep_s in seq:
+        if verbose:
+            print(f"-> {line}{state}  (wait {sleep_s:.3f}s)")
+        res = set_port_control(host, admin_port, con, line, state, timeout, verbose)
+        # continue even if response is None; user sees errors in stderr
+        if sleep_s and sleep_s > 0:
+            time.sleep(sleep_s)
+
+def main():
+    p = argparse.ArgumentParser(description="ser2net admin: restart / download sequences (explicit HI/LO)")
+    p.add_argument("--host", required=True, help="ser2net admin host/ip")
+    p.add_argument("--admin-port", type=int, required=True, help="ser2net admin port")
+    p.add_argument("--con", required=True, help="ser2net connection name (e.g. con1)")
+    p.add_argument("--action", choices=["restart", "download", "bootloader"], default="restart",
+                   help="restart or download (bootloader alias)")
+    p.add_argument("--pulse-ms", type=float, default=100.0, help="DTR pulse length in milliseconds")
+    p.add_argument("--step-delay-ms", type=float, default=20.0, help="short delay between steps in milliseconds")
+    p.add_argument("--tail-delay-ms", type=float, default=50.0, help="extra delay after sequence in milliseconds")
+    p.add_argument("--timeout", type=float, default=1.0, help="telnet connect/read timeout seconds")
+    p.add_argument("-v", "--verbose", action="store_true")
+    args = p.parse_args()
+
+    pulse_s = max(0.001, args.pulse_ms / 1000.0)
+    step_delay_s = max(0.0, args.step_delay_ms / 1000.0)
+    tail_delay_s = max(0.0, args.tail_delay_ms / 1000.0)
+
+    if args.verbose:
+        print(f"Admin {args.host}:{args.admin_port}  con={args.con}  action={args.action}")
+
+    # sequences use explicit physical HI/LO as requested
+    if args.action == "restart":
+        seq = [
+            ("RTS", "HI", step_delay_s),   # RTS HI
+            ("DTR", "LO", pulse_s),        # DTR LO (pulse start)
+            ("DTR", "HI", tail_delay_s),   # DTR HI (pulse end), then tail delay
+        ]
+    else:  # download / bootloader
+        # Ensure known starting state (RESET released), then enter download:
+        # 1) ensure DTR=HI (reset released)
+        # 2) RTS=LO (IO0 low)
+        # 3) DTR=LO -> wait pulse_ms
+        # 4) DTR=HI -> small delay
+        # 5) RTS=HI -> release IO0 (enter bootloader)
+        seq = [
+            ("DTR", "HI", step_delay_s),   # ensure reset released
+            ("RTS", "LO", step_delay_s),   # RTS LO (IO0 low)
+            ("DTR", "LO", pulse_s),        # DTR LO (reset asserted)
+            ("DTR", "HI", step_delay_s),   # DTR HI (reset released)
+            ("RTS", "HI", tail_delay_s),   # RTS HI (release IO0)
+        ]
+
+    run_sequence(args.host, args.admin_port, args.con, seq, args.timeout, args.verbose)
+
+    if args.verbose:
+        print("Sequence finished.")
+
+if __name__ == "__main__":
+    main()