From 9084e36978e66fb1429c8461bcc4ba5bf64c037e Mon Sep 17 00:00:00 2001
From: Stephan Hadinger <stephan.hadinger@gmail.com>
Date: Thu, 11 Nov 2021 14:44:54 +0100
Subject: [PATCH 1/2] Make serial more responsive at low bitrate

---
 lib/default/TasmotaSerial-3.3.0/src/TasmotaSerial.cpp | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/lib/default/TasmotaSerial-3.3.0/src/TasmotaSerial.cpp b/lib/default/TasmotaSerial-3.3.0/src/TasmotaSerial.cpp
index db3e3ccfa..57f695131 100644
--- a/lib/default/TasmotaSerial-3.3.0/src/TasmotaSerial.cpp
+++ b/lib/default/TasmotaSerial-3.3.0/src/TasmotaSerial.cpp
@@ -38,6 +38,8 @@ TasmotaSerial *tms_obj_list[16];
 #endif  // ESP8266
 #ifdef ESP32
 
+#include "driver/uart.h"
+
 #if CONFIG_IDF_TARGET_ESP32           // ESP32/PICO-D4
 static int tasmota_serial_index = 2;  // Allow UART2 and UART1 only
 #elif CONFIG_IDF_TARGET_ESP32S2       // ESP32-S2
@@ -155,6 +157,14 @@ bool TasmotaSerial::begin(uint32_t speed, uint32_t config) {
       if (serial_buffer_size > 256) {
         TSerial->setRxBufferSize(serial_buffer_size);
       }
+      // For low bit rate, below 9600, set the Full RX threshold at 10 bytes instead of the default 120
+      if (speed <= 9600) {
+        uart_set_rx_full_threshold(m_uart, 10);
+      }
+      // For bitrate below 115200, set the Rx time out to 5 chars instead of the default 10
+      if (speed < 115200) {
+        uart_set_rx_timeout(m_uart, 5);
+      }
     } else {
       m_valid = false;
     }

From a36331fe4742d980d1940eec3cd6d17407b7fa04 Mon Sep 17 00:00:00 2001
From: Stephan Hadinger <stephan.hadinger@gmail.com>
Date: Thu, 11 Nov 2021 19:22:15 +0100
Subject: [PATCH 2/2] Improved for zigbee

---
 .../TasmotaSerial-3.3.0/src/TasmotaSerial.cpp      | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/lib/default/TasmotaSerial-3.3.0/src/TasmotaSerial.cpp b/lib/default/TasmotaSerial-3.3.0/src/TasmotaSerial.cpp
index 57f695131..8b21de109 100644
--- a/lib/default/TasmotaSerial-3.3.0/src/TasmotaSerial.cpp
+++ b/lib/default/TasmotaSerial-3.3.0/src/TasmotaSerial.cpp
@@ -159,11 +159,21 @@ bool TasmotaSerial::begin(uint32_t speed, uint32_t config) {
       }
       // For low bit rate, below 9600, set the Full RX threshold at 10 bytes instead of the default 120
       if (speed <= 9600) {
+        // At 9600, 10 chars are ~10ms
         uart_set_rx_full_threshold(m_uart, 10);
+      } else if (speed < 115200) {
+        // At 19200, 120 chars are ~60ms
+        // At 76800, 120 chars are ~15ms
+        uart_set_rx_full_threshold(m_uart, 120);
+      } else {
+        // At 115200, 256 chars are ~20ms
+        // Zigbee requires to keep frames together, i.e. 256 bytes max
+        uart_set_rx_full_threshold(m_uart, 256);
       }
-      // For bitrate below 115200, set the Rx time out to 5 chars instead of the default 10
+      // For bitrate below 115200, set the Rx time out to 6 chars instead of the default 10
       if (speed < 115200) {
-        uart_set_rx_timeout(m_uart, 5);
+        // At 76800 the timeout is ~1ms
+        uart_set_rx_timeout(m_uart, 6);
       }
     } else {
       m_valid = false;