diff --git a/avr/devices/n20/defs.asm b/avr/devices/n20/defs.asm
index bc014f8..9f29d73 100644
--- a/avr/devices/n20/defs.asm
+++ b/avr/devices/n20/defs.asm
@@ -125,3 +125,11 @@
 
 
 
+; ---------------------------------------------------------------------------
+; CCS 811
+;
+
+.equ CCS811_ADDR = 0x5a ; or 0x5b
+
+
+
diff --git a/avr/devices/n20/main.asm b/avr/devices/n20/main.asm
index 8ce4396..765f501 100644
--- a/avr/devices/n20/main.asm
+++ b/avr/devices/n20/main.asm
@@ -65,6 +65,7 @@
 ;#define MODULES_OWI_MASTER
 ;#define MODULES_DS18B20
 #define MODULES_MOTION
+#define MODULES_CCS811
 
 ; ---------------------------------------------------------------------------
 ; defines for values
@@ -83,6 +84,8 @@
 
 ;.equ VALUE_ID_REED_CONF    = 0x81
 
+.equ VALUE_ID_DEBUG        = 0x7f
+
 
 
 ; ***************************************************************************
@@ -201,6 +204,10 @@ firmwareStart:   rjmp main
   .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"
@@ -241,6 +248,10 @@ programRamEnd:
   sramSendDs18b20TempTimer:    .byte 2
 #endif
 
+#ifdef MODULES_CCS811
+  sramCcs811Timer:             .byte 2
+#endif
+
 
 ; ***************************************************************************
 ; data in FLASH
@@ -277,6 +288,9 @@ timerList:
 #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