From e5366dbbe73ce69e68e2b2c545bfa26302c79c53 Mon Sep 17 00:00:00 2001
From: Stefan Agner <stefan@agner.ch>
Date: Tue, 10 Aug 2021 21:55:36 +0200
Subject: [PATCH] Add deassert_rts_dtr option to force RTS/DTR low when using
 miniterm (#2089)

---
 esphome/__main__.py                   | 14 +++++++++++++-
 esphome/components/logger/__init__.py |  2 ++
 esphome/const.py                      |  1 +
 3 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/esphome/__main__.py b/esphome/__main__.py
index 614bc12bae..b4770914a7 100644
--- a/esphome/__main__.py
+++ b/esphome/__main__.py
@@ -11,6 +11,7 @@ from esphome.config import iter_components, read_config, strip_default_ids
 from esphome.const import (
     CONF_BAUD_RATE,
     CONF_BROKER,
+    CONF_DEASSERT_RTS_DTR,
     CONF_LOGGER,
     CONF_OTA,
     CONF_PASSWORD,
@@ -99,10 +100,21 @@ def run_miniterm(config, port):
     baud_rate = config["logger"][CONF_BAUD_RATE]
     if baud_rate == 0:
         _LOGGER.info("UART logging is disabled (baud_rate=0). Not starting UART logs.")
+        return
     _LOGGER.info("Starting log output from %s with baud rate %s", port, baud_rate)
 
     backtrace_state = False
-    with serial.Serial(port, baudrate=baud_rate) as ser:
+    ser = serial.Serial()
+    ser.baudrate = baud_rate
+    ser.port = port
+
+    # We can't set to False by default since it leads to toggling and hence
+    # ESP32 resets on some platforms.
+    if config["logger"][CONF_DEASSERT_RTS_DTR]:
+        ser.dtr = False
+        ser.rts = False
+
+    with ser:
         while True:
             try:
                 raw = ser.readline()
diff --git a/esphome/components/logger/__init__.py b/esphome/components/logger/__init__.py
index 8d79c96f63..55178941ec 100644
--- a/esphome/components/logger/__init__.py
+++ b/esphome/components/logger/__init__.py
@@ -7,6 +7,7 @@ from esphome.automation import LambdaAction
 from esphome.const import (
     CONF_ARGS,
     CONF_BAUD_RATE,
+    CONF_DEASSERT_RTS_DTR,
     CONF_FORMAT,
     CONF_HARDWARE_UART,
     CONF_ID,
@@ -104,6 +105,7 @@ CONFIG_SCHEMA = cv.All(
             cv.GenerateID(): cv.declare_id(Logger),
             cv.Optional(CONF_BAUD_RATE, default=115200): cv.positive_int,
             cv.Optional(CONF_TX_BUFFER_SIZE, default=512): cv.validate_bytes,
+            cv.Optional(CONF_DEASSERT_RTS_DTR, default=False): cv.boolean,
             cv.Optional(CONF_HARDWARE_UART, default="UART0"): uart_selection,
             cv.Optional(CONF_LEVEL, default="DEBUG"): is_log_level,
             cv.Optional(CONF_LOGS, default={}): cv.Schema(
diff --git a/esphome/const.py b/esphome/const.py
index 9f3ce13b46..cd095677b3 100644
--- a/esphome/const.py
+++ b/esphome/const.py
@@ -163,6 +163,7 @@ CONF_DATA_TEMPLATE = "data_template"
 CONF_DAYS_OF_MONTH = "days_of_month"
 CONF_DAYS_OF_WEEK = "days_of_week"
 CONF_DC_PIN = "dc_pin"
+CONF_DEASSERT_RTS_DTR = "deassert_rts_dtr"
 CONF_DEBOUNCE = "debounce"
 CONF_DECELERATION = "deceleration"
 CONF_DEFAULT_MODE = "default_mode"