From 39615c070005b0251893060e2da3dfcf537f88a3 Mon Sep 17 00:00:00 2001
From: digiblur <3240875+digiblur@users.noreply.github.com>
Date: Wed, 17 Apr 2019 21:41:58 -0500
Subject: [PATCH] Add Tuya Dimmer 10 second heartbeat

Some newer dimmer modules require the stock firmware method of sending a heartbeat packet every 10-11 seconds to the secondary MCU.  This was tested on 2 other Tuya based dimmers that did not require this heartbeat packet and no adverse impacts have been found.
---
 sonoff/xdrv_16_tuyadimmer.ino | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/sonoff/xdrv_16_tuyadimmer.ino b/sonoff/xdrv_16_tuyadimmer.ino
index d43e6397e..ffb44adab 100644
--- a/sonoff/xdrv_16_tuyadimmer.ino
+++ b/sonoff/xdrv_16_tuyadimmer.ino
@@ -52,6 +52,7 @@ uint8_t tuya_cmd_status = 0;                // Current status of serial-read
 uint8_t tuya_cmd_checksum = 0;              // Checksum of tuya command
 uint8_t tuya_data_len = 0;                  // Data lenght of command
 int8_t tuya_wifi_state = -2;                // Keep MCU wifi-status in sync with WifiState()
+uint8_t tuya_heartbeat_timer = 0;           // 10 second heartbeat timer for tuya module
 
 char *tuya_buffer = nullptr;                // Serial receive buffer
 int tuya_byte_counter = 0;                  // Index in serial receive buffer
@@ -294,6 +295,7 @@ void TuyaInit(void)
       TuyaSendCmd(TUYA_CMD_MCU_CONF);
     }
   }
+  tuya_heartbeat_timer = 0; // init heartbeat timer when dimmer init is done
 }
 
 void TuyaSerialInput(void)
@@ -410,6 +412,11 @@ bool Xdrv16(uint8_t function)
         break;
       case FUNC_EVERY_SECOND:
         if(TuyaSerial && tuya_wifi_state!=WifiState()) { TuyaSetWifiLed(); }
+        tuya_heartbeat_timer++;
+        if (tuya_heartbeat_timer > 10) {
+           tuya_heartbeat_timer = 0;
+           TuyaSendCmd(TUYA_CMD_HEARTBEAT);
+        } 
         break;
       case FUNC_SET_CHANNELS:
         result = TuyaSetChannels();