diff --git a/avr/devices/0BUILD b/avr/devices/0BUILD
index 6a380c1..9662863 100644
--- a/avr/devices/0BUILD
+++ b/avr/devices/0BUILD
@@ -36,6 +36,7 @@
n24
n25
n26
+ n27
t03
diff --git a/avr/devices/n27/.gitignore b/avr/devices/n27/.gitignore
new file mode 100644
index 0000000..8e0618c
--- /dev/null
+++ b/avr/devices/n27/.gitignore
@@ -0,0 +1,2 @@
+*.eep.hex
+*.obj
diff --git a/avr/devices/n27/0BUILD b/avr/devices/n27/0BUILD
new file mode 100644
index 0000000..081044b
--- /dev/null
+++ b/avr/devices/n27/0BUILD
@@ -0,0 +1,22 @@
+
+
+
+
+
+ boot
+ main
+
+
+
+ aqua_n27.xml
+
+
+
+ defs.asm
+ README
+
+
+
+
+
+
diff --git a/avr/devices/n27/README b/avr/devices/n27/README
new file mode 100644
index 0000000..f79221c
--- /dev/null
+++ b/avr/devices/n27/README
@@ -0,0 +1,15 @@
+
+N27
+===
+
+- Role: Air quality and climate sensors
+- MCU: AtTiny84
+- Connection: RJ45
+- Predecessor: N24, N23, N19
+- Periphery:
+ - PIR sensor (AMN31112)
+ - TWI interface
+ - SI7021 temperature and humidity sensor
+ or
+ - SGP-30/40 air quality sensor
+
diff --git a/avr/devices/n27/aqua_n27.xml b/avr/devices/n27/aqua_n27.xml
new file mode 100644
index 0000000..9238a60
--- /dev/null
+++ b/avr/devices/n27/aqua_n27.xml
@@ -0,0 +1,27 @@
+
+
+ AQUA
+ N
+ 27
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
diff --git a/avr/devices/n27/boot/0BUILD b/avr/devices/n27/boot/0BUILD
new file mode 100644
index 0000000..444ac6f
--- /dev/null
+++ b/avr/devices/n27/boot/0BUILD
@@ -0,0 +1,32 @@
+
+
+
+
+
+
+
+ -I $(builddir)
+ -I $(srcdir)
+ -I $(topsrcdir)/avr
+ -I $(topbuilddir)/avr
+
+
+
+
+ boot.asm
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
diff --git a/avr/devices/n27/boot/boot.asm b/avr/devices/n27/boot/boot.asm
new file mode 100644
index 0000000..767f207
--- /dev/null
+++ b/avr/devices/n27/boot/boot.asm
@@ -0,0 +1,157 @@
+; ***************************************************************************
+; copyright : (C) 2025 by Martin Preuss
+; email : martin@libchipcard.de
+;
+; ***************************************************************************
+; * This file is part of the project "AqHome". *
+; * Please see toplevel file COPYING of that project for license details. *
+; ***************************************************************************
+
+
+; ***************************************************************************
+; Source file for base system node on AtTiny 84
+;
+; This is for the maintenance system (i.e. the flash loader).
+;
+; All definitions and changes should go into this file.
+; ***************************************************************************
+
+.equ clock=1000000 ; Define the clock frequency
+
+.nolist
+.include "include/tn84def.inc" ; Define device ATtiny84
+.list
+
+.include "version.asm"
+.include "../defs.asm"
+
+.include "common/calls.asm"
+.include "devices/all/defs.asm"
+
+
+#define COM_ACCEPT_ALL_DEST
+
+
+
+; ***************************************************************************
+; defines
+
+; ---------------------------------------------------------------------------
+; generic
+
+.include "common/utils_wait.asm"
+.include "modules/com2/defs.asm"
+.include "modules/comproto/defs.asm"
+
+
+
+; ---------------------------------------------------------------------------
+; firmware settings
+
+
+
+; ---------------------------------------------------------------------------
+; LED
+
+.equ LED_DDR = DDRA
+.equ LED_PORT = PORTA
+.equ LED_PIN = PINA
+.equ LED_PINNUM = PORTA3
+
+
+; ***************************************************************************
+; code segment
+
+.cseg
+.org 0x0000
+
+
+
+; ---------------------------------------------------------------------------
+; Reset and interrupt vectors
+; rjmp start ; Reset vector
+ rjmp main ; Reset vector
+ reti ; EXT_INT0
+ reti ; PCI0
+ reti ; PCI1
+ reti ; WATCHDOG
+ reti ; ICP1
+ reti ; OC1A
+ reti ; OC1B
+ reti ; OVF1
+ reti ; OC0A
+ reti ; OC0B
+ reti ; OVF0
+ reti ; ACI
+ reti ; ADCC
+ reti ; ERDY
+ reti ; USI_STR
+ reti ; USI_OVF
+
+
+devInfoBlock: ; 12 bytes
+devInfoManufacturer: .db 'A', 'Q', 'U', 'A'
+devInfoId: .db DEVICEINFO_ID, 0
+devInfoVersion: .db DEVICEINFO_VERSION, DEVICEINFO_REVISION ; version, revision
+firmwareVersion: .db FIRMWARE_VARIANT_BOOT, FIRMWARE_VERSION_MAJOR
+ .db FIRMWARE_VERSION_MINOR, FIRMWARE_VERSION_PATCHLEVEL
+
+firmwareStart: rjmp main ; will be overwritten when flashing
+
+
+
+; ***************************************************************************
+; main code
+
+
+.org BOOTLOADER_ADDR
+
+
+main:
+ rjmp bootLoader ; this routine is in modules/bootloader/main.asm
+
+
+
+; ***************************************************************************
+; includes
+
+.include "common/utils_wait_fixed.asm"
+.include "common/utils_copy_from_flash.asm"
+.include "common/utils_copy_sdram.asm"
+
+.include "modules/flash/defs.asm"
+.include "modules/flash/eeprom.asm"
+.include "modules/flash/io.asm"
+.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"
+.include "modules/network/msg/defs.asm"
+.include "modules/network/msg/crc.asm"
+
+;.include "common/debug.asm"
+
+
+
+systemSetSpeed:
+.if clock == 8000000
+ ldi r16, (1<
+
+
+
+
+
+
+ -I $(builddir)
+ -I $(srcdir)
+ -I $(topsrcdir)/avr
+ -I $(topbuilddir)/avr
+
+
+
+
+ main.asm
+
+
+
+
+
+
+
+
+
+
+
+ data.asm
+
+
+
+
+
+
diff --git a/avr/devices/n27/main/data.asm b/avr/devices/n27/main/data.asm
new file mode 100644
index 0000000..31ccc2f
--- /dev/null
+++ b/avr/devices/n27/main/data.asm
@@ -0,0 +1,14 @@
+; ***************************************************************************
+; copyright : (C) 2025 by Martin Preuss
+; email : martin@libchipcard.de
+;
+; ***************************************************************************
+; * This file is part of the project "AqHome". *
+; * Please see toplevel file COPYING of that project for license details. *
+; ***************************************************************************
+
+
+
+.dseg
+
+
diff --git a/avr/devices/n27/main/main.asm b/avr/devices/n27/main/main.asm
new file mode 100644
index 0000000..7a1e810
--- /dev/null
+++ b/avr/devices/n27/main/main.asm
@@ -0,0 +1,224 @@
+; ***************************************************************************
+; copyright : (C) 2025 by Martin Preuss
+; email : martin@libchipcard.de
+;
+; ***************************************************************************
+; * This file is part of the project "AqHome". *
+; * Please see toplevel file COPYING of that project for license details. *
+; ***************************************************************************
+
+
+
+
+; ***************************************************************************
+; Source file for temperature sensor node on AtTiny 84
+;
+; This is for the full system (i.e. not the boot loader).
+;
+; All definitions and changes should go into this file.
+;
+;
+; ***************************************************************************
+
+
+.equ clock=1000000 ; Define the clock frequency
+;.equ clock=8000000 ; Define the clock frequency
+
+
+
+.nolist
+.include "include/tn84def.inc" ; Define device ATtiny84
+.list
+
+.include "../defs.asm"
+.include "./data.asm"
+
+.include "version.asm"
+.include "devices/all/defs.asm"
+.include "common/calls.asm"
+.include "common/utils_wait.asm"
+
+
+
+; ***************************************************************************
+; defines
+
+; ---------------------------------------------------------------------------
+; generic
+
+.equ NET_BUFFERS_NUM = 6
+.equ NET_BUFFERS_SIZE = 32
+
+.equ PROGRAM_SENSOR_INTERVAL_SECS = 60
+.equ PROGRAM_STATS_INTERVAL_MINS = 10
+
+
+
+; ---------------------------------------------------------------------------
+; firmware settings including list of modules used
+
+; #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 MODULES_SI7021
+#define MODULES_SGP30
+;#define MODULES_SGP40
+;#define MODULES_STATS
+;#define MODULES_OWI_MASTER
+;#define MODULES_DS18B20
+#define MODULES_MOTION
+;#define MODULES_CCS811
+#define MODULES_BRIGHTNESS
+
+#define APPS_NETWORK
+#define APPS_MOTION
+#define APPS_REPORTSENSORS
+#define APPS_STATS
+
+
+
+; ---------------------------------------------------------------------------
+; defines for values
+
+.equ VALUE_ID_SI7021_TEMP = 0x01
+.equ VALUE_ID_SI7021_HUM = 0x02
+
+.equ VALUE_ID_ADC = 0x03
+;.equ VALUE_ID_DS18B20_TEMP = 0x06
+.equ VALUE_ID_MOTION = 0x07
+
+.equ VALUE_ID_SGP40_TVOC = 0x08
+
+.equ VALUE_ID_SGP30_TVOC = 0x09
+.equ VALUE_ID_SGP30_CO2 = 0x0a
+
+.equ VALUE_ID_BRIGHTNESS = 0x0b
+
+;.equ VALUE_ID_REED_CONF = 0x81
+
+.equ VALUE_ID_DEBUG = 0x7f
+
+.equ VALUE_ID_LEDSIMPLE_TIMING = 0x88
+
+
+
+
+
+; ***************************************************************************
+; code segment
+
+.cseg
+.org 000000
+
+
+
+; ---------------------------------------------------------------------------
+; Reset and interrupt vectors (will be removed as soon as we can flash data over COM)
+
+; rjmp main ; Reset vector
+ rjmp BOOTLOADER_ADDR ; Reset vector ; use this for flashed system
+ reti ; EXT_INT0
+ rjmp UART_BitBang_PcintIsr ; PCI0
+ reti ; PCI1
+ reti ; WATCHDOG
+ reti ; ICP1
+ reti ; OC1A
+ reti ; OC1B
+ reti ; OVF1
+ rjmp baseTimerIrqOC0A ; OC0A
+ reti ; OC0B
+ reti ; OVF0
+ reti ; ACI
+ reti ; ADCC
+ reti ; ERDY
+ reti ; USI_STR
+ reti ; USI_OVF
+
+
+devInfoBlock: ; 12 bytes
+devInfoManufacturer: .db 'A', 'Q', 'U', 'A'
+devInfoId: .db DEVICEINFO_ID, 0
+devInfoVersion: .db DEVICEINFO_VERSION, DEVICEINFO_REVISION ; version, revision
+firmwareVersion: .db FIRMWARE_VARIANT_TEMP_WINDOW, FIRMWARE_VERSION_MAJOR
+ .db FIRMWARE_VERSION_MINOR, FIRMWARE_VERSION_PATCHLEVEL
+
+
+
+; ---------------------------------------------------------------------------
+; @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 "devices/all/hw_tn84.asm"
+.include "devices/all/includes.asm"
+
+
+
+; ---------------------------------------------------------------------------
+; defines for network interface
+
+.equ netInterfaceData = uart_bitbang_iface
+
+
+