diff --git a/avr/devices/0BUILD b/avr/devices/0BUILD
index 938763a..330a10b 100644
--- a/avr/devices/0BUILD
+++ b/avr/devices/0BUILD
@@ -26,6 +26,7 @@
     all
     c01
     n16
+    n20
     n21
     n22
     n23
diff --git a/avr/devices/n20/boot.asm b/avr/devices/n20/boot.asm
index 4e59cfc..00c7184 100644
--- a/avr/devices/n20/boot.asm
+++ b/avr/devices/n20/boot.asm
@@ -12,8 +12,9 @@
 .include "include/tn84def.inc" ; Define device ATtiny84
 .list
 
+.include "version.asm"
 .include "./defs.asm"
-.include "defs_all.asm"
+.include "devices/all/defs.asm"
 
 
 
@@ -32,9 +33,6 @@
 ; ---------------------------------------------------------------------------
 ; firmware settings
 
-.equ FIRMWARE_VERSION_MAJOR       = 0
-.equ FIRMWARE_VERSION_MINOR       = 0
-.equ FIRMWARE_VERSION_PATCHLEVEL  = 1
 
 
 
@@ -113,6 +111,7 @@ main:
 .include "modules/flash/io_attn.asm"
 .include "modules/flash/io_bitbang.asm"
 .include "modules/flash/flash1p.asm"
+.include "modules/flash/flashxp.asm"
 .include "modules/flash/flashprocess.asm"
 .include "modules/flash/wait.asm"
 .include "modules/bootloader/main.asm"
@@ -121,7 +120,6 @@ main:
 
 
 
-
 systemSetSpeed:
 .if clock == 8000000
   ldi r16, (1<<CLKPCE)
diff --git a/avr/devices/n20/main.asm b/avr/devices/n20/main.asm
index 765f501..8efd2b8 100644
--- a/avr/devices/n20/main.asm
+++ b/avr/devices/n20/main.asm
@@ -30,8 +30,11 @@
 .include "include/tn84def.inc" ; Define device ATtiny84
 .list
 
+.include "version.asm"
 .include "./defs.asm"
-.include "defs_all.asm"
+.include "devices/all/defs.asm"
+
+.include "common/utils_wait.asm"
 
 
 
@@ -41,31 +44,37 @@
 ; ---------------------------------------------------------------------------
 ; generic
 
+.equ NET_BUFFERS_NUM            = 6
+.equ NET_BUFFERS_SIZE           = 32
 
-.include "common/utils_wait.asm"
 
 
 ; ---------------------------------------------------------------------------
 ; firmware settings including list of modules used
 
-.equ FIRMWARE_VERSION_MAJOR       = 0
-.equ FIRMWARE_VERSION_MINOR       = 0
-.equ FIRMWARE_VERSION_PATCHLEVEL  = 1
-
-
-#define MODULES_TIMER
-#define MODULES_COM
-#define MODULES_COM_WITH_ADDR_PROTO
+; #define MODULES_TIMER
+#define MODULES_CLOCK
 #define MODULES_LED_SIMPLE
+#define MODULES_NETWORK
+#define MODULES_UART_BITBANG
 #define MODULES_TWI_MASTER
 ;#define MODULES_LCD
-#define LCD_MINIMAL_FONT
+;#define LCD_MINIMAL_FONT
 #define MODULES_SI7021
-#define MODULES_STATS
+;#define MODULES_STATS
 ;#define MODULES_OWI_MASTER
 ;#define MODULES_DS18B20
 #define MODULES_MOTION
-#define MODULES_CCS811
+;#define MODULES_TCRT1000
+;#define MODULES_CCS811
+
+#define APPS_NETWORK
+#define APPS_MOTION
+;#define APPS_DOOR
+#define APPS_REPORTSENSORS
+#define APPS_STATS
+
+
 
 ; ---------------------------------------------------------------------------
 ; defines for values
@@ -86,6 +95,8 @@
 
 .equ VALUE_ID_DEBUG        = 0x7f
 
+.equ VALUE_ID_LEDSIMPLE_TIMING = 0x88
+
 
 
 ; ***************************************************************************
@@ -102,7 +113,7 @@
 ;	rjmp main ; Reset vector
         rjmp BOOTLOADER_ADDR ; Reset vector  ; use this for flashed system
 	reti ; EXT_INT0
-	rjmp uartBitbangIsrPcint0 ; PCI0
+	rjmp UART_BitBang_PcintIsr ; PCI0
 	reti ; PCI1
 	reti ; WATCHDOG
 	reti ; ICP1
@@ -126,351 +137,82 @@ devInfoVersion:      .db DEVICEINFO_VERSION, DEVICEINFO_REVISION             ; v
 firmwareVersion:     .db FIRMWARE_VARIANT_TEMP_WINDOW, FIRMWARE_VERSION_MAJOR
                      .db FIRMWARE_VERSION_MINOR, FIRMWARE_VERSION_PATCHLEVEL
 
-firmwareStart:   rjmp main
+; ---------------------------------------------------------------------------
+; @routine firmwareStart @global
+
+firmwareStart:
+  rjmp main
+; @end
+
+
+
+; ---------------------------------------------------------------------------
+; @routine onSystemStart
+
+onSystemStart:
+  ret
+; @end
+
+
+
+; ---------------------------------------------------------------------------
+; @routine onMessageReceived
+;
+; Called on every message received
+
+onMessageReceived:
+  clc
+  ret
+; @end
+
+
+
+; ---------------------------------------------------------------------------
+; @routine onEvery100ms
+;
+; Called every 100ms. Add your routine calls here. No arguments, no results.
+
+onEvery100ms:
+onEverySecond:
+onEveryMinute:
+onEveryHour:
+onEveryDay:
+  ret
+; @end
+
+
+
+; ---------------------------------------------------------------------------
+; @routine onEveryLoop
+;
+; Called on every loop (i.e. after awakening from sleep).
+;
+onEveryLoop:
+  ret
+; @end
+
+
+
 
 
 ; ***************************************************************************
 ; includes
 
-.include "common/utils.asm"
-.include "common/utils_wait_fixed.asm"
-.include "common/utils_copy_from_flash.asm"
-.include "common/utils_copy_sdram.asm"
-.include "common/crc8.asm"
-
-.include "modules/basetimer/main.asm"
-
-#ifdef MODULES_TIMER
-  .include "modules/timer/main.asm"
-#endif
-#ifdef MODULES_LED
-.include "modules/led/main.asm"
-#endif
-#ifdef MODULES_LED_SIMPLE
-.include "modules/led_simple/main.asm"
-#endif
-#ifdef MODULES_COM
-  .include "modules/com2/defs.asm"
-  .include "modules/com2/main.asm"
-  .include "modules/com2/buffer.asm"
-  .include "modules/uart_bitbang/defs.asm"
-  .include "modules/uart_bitbang/main.asm"
-  .include "modules/uart_bitbang/bytelevel.asm"
-  .include "modules/uart_bitbang/packetlevel.asm"
-  #ifdef MODULES_COM_WITH_ADDR_PROTO
-    .include "modules/comproto/defs.asm"
-    .include "modules/comproto/main.asm"
-    .include "modules/comproto/addr.asm"
-    .include "modules/comproto/msg_recvstats.asm"
-    .include "modules/comproto/msg_sendstats.asm"
-    .include "modules/comproto/msg_sysstats.asm"
-    .include "modules/comproto/msg_memstats.asm"
-    .include "modules/comproto/msg_pong.asm"
-    .include "modules/comproto/msg_value.asm"
-    .include "modules/comproto/msg_device.asm"
-    .include "modules/comproto/msg_reboot.asm"
-  #endif
-  #ifdef MODULES_LCD
-    .include "modules/com2/screen.asm"
-    .include "modules/comproto/screen.asm"
-  #endif
-#endif
-#ifdef MODULES_TWI_MASTER
-  .include "modules/twimaster/main.asm"
-#endif
-#ifdef MODULES_OWI_MASTER
-  .include "modules/owimaster/main.asm"
-#endif
-#ifdef MODULES_LCD
-  .include "modules/lcd/main.asm"
-#endif
-#ifdef MODULES_SI7021
-  .include "modules/si7021/main.asm"
-#endif
-#ifdef MODULES_DS18B20
-  .include "modules/ds18b20/main.asm"
-#endif
-#ifdef MODULES_STATS
-  .include "modules/stats/main.asm"
-#endif
-#ifdef MODULES_CNY70
-  .include "modules/cny70/main.asm"
-#endif
-#ifdef MODULES_REED
-  .include "modules/reed/main.asm"
-#endif
-
-#ifdef MODULES_MOTION
-  .include "modules/motion/main.asm"
-#endif
-
-#ifdef MODULES_CCS811
-  .include "modules/ccs811/main.asm"
-#endif
-
-; test
-;#include "modules/uart_irq/defs.asm"
-;#include "modules/uart_irq/iface.asm"
-;#include "modules/uart_irq/iface1.asm"
-
-
-; ***************************************************************************
-; data in SRAM
-
-.dseg
-
-programRamBegin:
-#ifdef MODULES_LCD
-  screenCounter:               .byte 1
-#endif
-
-programRamEnd:
-
-
-
-#ifdef MODULES_LCD
-  sramTimerWriteStats:         .byte 2
-  sramTimerScreen:             .byte 2
-#endif
-#ifdef MODULES_SI7021
-  sramTimerSI7021Measure:      .byte 2
-  sramTimerSI7021SendTemp:     .byte 2
-  sramTimerSI7021SendHumidity: .byte 2
-#endif
-#ifdef MODULES_CNY70
-  sramTimerCny70SendAdc:       .byte 2
-#endif
-#ifdef MODULES_LCD
-  sramPeriodicalLcdMark:       .byte 2
-#endif
-#ifdef MODULES_DS18B20
-  sramDs18b20Timer:            .byte 2
-  sramSendDs18b20TempTimer:    .byte 2
-#endif
-
-#ifdef MODULES_CCS811
-  sramCcs811Timer:             .byte 2
-#endif
-
-
-; ***************************************************************************
-; data in FLASH
-
-.cseg
+.include "devices/all/hw_tn84.asm"
+.include "devices/all/includes.asm"
 
 
 
 ; ---------------------------------------------------------------------------
-; timer list
+; defines for network interface
 
-
-timerList:
-;     SRAM variable/counter        routine                     flags                secs (0=don't start or restart)
-#ifdef MODULES_COM_WITH_ADDR_PROTO
-  .dw cproAddresModeTimer,         CPRO_Address_OnTimer,       0,                   0     ; (no restart)
-#endif
-#ifdef MODULES_STATS
-  .dw statsSendTimer,              Stats_Timer,                TIMER_FLAGS_IF_ADDR, 9000   ; every 15m
-#endif
-#ifdef MODULES_LCD
-;  .dw sramPeriodicalLcdMark,       periodicalLcdMark,          0,                    20   ; every 2s
-;  .dw sramTimerWriteStats,         writeStats,                 0,                   100
-  .dw sramTimerScreen,              printScreen,                TIMER_FLAGS_IF_ADDR,  50    ; every 5s
-#endif
-#ifdef MODULES_SI7021
-  .dw sramTimerSI7021Measure,      SI7021_OnTimer,             0,                   300    ; every 30s
-  .dw sramTimerSI7021SendTemp,     sendSI7021Temp,             TIMER_FLAGS_IF_ADDR, 600    ; every 60s
-  .dw sramTimerSI7021SendHumidity, sendSI7021Humidity,         TIMER_FLAGS_IF_ADDR, 600    ; every 60s
-#endif
-#ifdef MODULES_CNY70
-  .dw sramTimerCny70SendAdc,       CNY70_OnTimer,              TIMER_FLAGS_IF_ADDR, 50     ; every 5s
-#endif
-#ifdef MODULES_DS18B20
-  .dw sramDs18b20Timer,            Ds18b20_OnTimer,            0,                   300    ; every 30s
-  .dw sramSendDs18b20TempTimer,    sendDs18b20Temp,            TIMER_FLAGS_IF_ADDR, 600    ; every 60s
-#endif
-#ifdef MODULES_CCS811
-  .dw sramCcs811Timer,             CCS811_OnTimer,             0,                   10     ; every 1s
-#endif
-  .dw 0 ; end of list
+.equ netInterfaceData = uart_bitbang_iface
 
 
 
 
 
-.include "main_all.asm"
 
 
 
-systemSetSpeed:
-.if clock == 8000000
-  ldi r16, (1<<CLKPCE)
-  ldi r17, 0
-  out CLKPR, r16
-  out CLKPR, r17
-.endif
-  ret
-
-
-systemSetBootSpeed:
-.if clock == 8000000
-  ldi r16, (1<<CLKPCE)
-  ldi r17, (1<<CLKPS1) | (1<<CLKPS0)
-  out CLKPR, r16
-  out CLKPR, r17
-.endif
-  ret
-
-
-
-; ---------------------------------------------------------------------------
-; Called on first time run, i.e. on system start. No arguments, no results.
-
-onSystemStart:
-  ldi xh, HIGH(programRamBegin)
-  ldi xl, LOW(programRamBegin)
-  clr r16
-  ldi r17, (programRamEnd-programRamBegin)
-  rcall Utils_FillSram
-  ret
-
-
-#ifdef MODULES_LCD
-
-printScreen:
-  lds r16, screenCounter
-  tst r16
-  brne printScreen_l1
-  rcall CPRO_Screen
-  rjmp printScreen_counter
-printScreen_l1:
-  cpi r16, 1
-  brne printScreen_l2
-  rcall COM2_Screen_RecvStats
-  rjmp printScreen_counter
-printScreen_l2:
-;  cpi r16, 2
-;  brne printScreen_l3
-;  rcall COM2_Screen_SendStats
-;  rjmp printScreen_counter
-printScreen_l3:
-  ; add more screens here
-
-printScreen_counter:
-  lds r16, screenCounter
-  inc r16
-  cpi r16, 2 ; number of screens
-  brcs printScreen_store
-  clr r16
-printScreen_store:
-  sts screenCounter, r16
-printScreen_end:
-  ret
-
-
-;periodicalLcdMark:
-;  rcall printTimerMark
-;  ret
-
-
-;writeStats:
-;  rcall printSendStats
-;  ret
-#endif
-
-
-#ifdef MODULES_SI7021
-
-sendSI7021Humidity:
-  rcall SI7021_SendHumidity
-  brcs sendSI7021Humidity_okay
-  ; set timer to 1s to retry later
-  ldi xl, LOW(sramTimerSI7021SendHumidity)
-  ldi xh, HIGH(sramTimerSI7021SendHumidity)
-  rjmp Timer_SetValueTo1s
-sendSI7021Humidity_okay:
-  ret
-
-
-sendSI7021Temp:
-  rcall SI7021_SendTemp
-  brcs sendSI7021Temp_okay
-  ; set timer to 1s to retry later
-  ldi xl, LOW(sramTimerSI7021SendTemp)
-  ldi xh, HIGH(sramTimerSI7021SendTemp)
-  rjmp Timer_SetValueTo1s
-sendSI7021Temp_okay:
-  ret
-#endif
-
-
-#ifdef MODULES_DS18B20
-sendDs18b20Temp:
-  rcall Ds18b20_SendTemp
-  brcs sendDs18b20Temp_okay
-  ; set timer to 1s to retry later
-  ldi xl, LOW(sramSendDs18b20TempTimer)
-  ldi xh, HIGH(sramSendDs18b20TempTimer)
-  rjmp Timer_SetValueTo1s
-sendDs18b20Temp_okay:
-  ret
-#endif
-
-
-; ---------------------------------------------------------------------------
-; Called every 100ms. Add your routine calls here. No arguments, no results.
-
-onEvery100ms:
-#ifdef MODULES_LED_SIMPLE
-  rcall LedSimple_Every100ms
-#endif
-
-#ifdef MODULES_REED
-  rcall REED_Every100ms
-#endif
-
-#ifdef MODULES_MOTION
-  rcall Motion_Every100ms
-#endif
-  ret
-
-
-
-; ---------------------------------------------------------------------------
-; @routine onPacketReceived:
-;
-; Called after a packet was received via COM module. Add your routine calls here.
-;
-; The packet will be released in any case after return from this call.
-;
-; @return CFLAG set if message handled, cleared otherwise
-; @param X  pointer to received buffer
-; @clobbers all
-
-onPacketReceived:
-#ifdef MODULES_MOTION_LIGHT
-  rcall MotionLight_OnPacketReceived
-  brcs onPacketReceived_end
-#endif
-
-#ifdef MODULES_SK6812
-  rcall SK6812_OnPacketReceived
-  brcs onPacketReceived_end
-#endif
-
-#ifdef MODULES_REED
-  rcall REED_OnPacketReceived
-  brcs onPacketReceived_end
-#endif
-
-#ifdef MODULES_COM
-  rcall CPRO_OnPacketReceived
-  brcs onPacketReceived_end
-#endif
-
-  clc
-onPacketReceived_end:
-  ret
-; @end
-
 
diff --git a/flashnode.sh b/flashnode.sh
index ccb0196..2e703b5 100755
--- a/flashnode.sh
+++ b/flashnode.sh
@@ -23,6 +23,13 @@ case $NODE in
        EFUSE_ARG="-U efuse:w:0xFE:m"
        FILE_ARG="-U flash:w:./0-build/avr/devices/n16/boot/n16_boot.hex"
        ;;
+  n20)
+       DEVICE_ARG="-p t84"
+       HFUSE_ARG="-U hfuse:w:0xD7:m"
+       LFUSE_ARG=""
+       EFUSE_ARG="-U efuse:w:0xFE:m"
+       FILE_ARG="-U flash:w:./0-build/avr/devices/n20/n20_boot.hex"
+       ;;
   n21)
        DEVICE_ARG="-p t84"
        HFUSE_ARG="-U hfuse:w:0xD7:m"