fixed network for MEGA+Wiz5500,

Mega DMX OUT on TX1 pin now (same with DUE),
E81 port Modbus dimmer settings for MEGA. AVR Binaries

check_custom_build_flags_mega2560.sh

@@ -1,6 +1,8 @@
 #! /bin/bash
 CUSTOM_BUILD_FLAGS_FILE=custom-build-flags/build_flags_mega2560.sh
 export FLAGS="$FLAGS -DPIO_SRC_REV="$(git log --pretty=format:%h_%ad -1 --date=short)
+export FLAGS="$FLAGS -DMODBUS_DIMMER_PARAM=SERIAL_8E1"
+export FLAGS="$FLAGS -DAVR_DMXOUT_PIN=18"
 if [ -f $CUSTOM_BUILD_FLAGS_FILE ]; then
     source $CUSTOM_BUILD_FLAGS_FILE
 fi