diff --git a/avr/modules/uart_bitbang2/iface.asm b/avr/modules/uart_bitbang2/iface.asm
index 99167ee..735c9c5 100644
--- a/avr/modules/uart_bitbang2/iface.asm
+++ b/avr/modules/uart_bitbang2/iface.asm
@@ -20,6 +20,35 @@
 
 
 
+; ***************************************************************************
+; macros
+
+
+.macro mUartBitbangSetupInt0
+  inr r16, MCUCR
+  cbr r16, (1<<ISC01) | (1<<ISC00)
+  sbr r16, (1<<ISC01) | (0<<ISC00)        ; falling edge of ATTN
+  outr MCUCR, r16
+;  sbr r16, (0<<ISC01) | (0<<ISC00)         ; low level triggers
+  inr r16, COM_IRQ_ADDR_ATTN             ; enable irq for ATTN line
+  sbr r16, (1<<COM_IRQ_BIT_ATTN)
+  outr COM_IRQ_ADDR_ATTN, r16
+.endmacro
+
+
+
+.macro mUartBitbangSetupPci
+  sbi COM_IRQ_ADDR_ATTN, COM_IRQ_BIT_ATTN ; enable pin change irq for ATTN line
+  in r16, GIMSK                           ; enable pin change irq PCIE0 or PCIE1
+  ori r16, (1<<COM_IRQ_GIMSK_ATTN)
+  out GIMSK, R16
+  ldi r16, (1<<COM_IRQ_GIFR_ATTN)         ; clear pending irq by writing 1 to ATTN bit
+  out GIFR, r16
+.endmacro
+
+
+
+
 ; ***************************************************************************
 ; data
 
@@ -57,29 +86,12 @@ UART_BitBang_Init:
   ; enable IRQ
 .ifdef INT0
   .if COM_IRQ_BIT_ATTN == INT0
-    inr r16, MCUCR
-    cbr r16, (1<<ISC01) | (1<<ISC00)
-    sbr r16, (1<<ISC01) | (0<<ISC00)        ; falling edge of ATTN
-    outr MCUCR, r16
-  ;  sbr r16, (0<<ISC01) | (0<<ISC00)         ; low level triggers
-    inr r16, COM_IRQ_ADDR_ATTN             ; enable irq for ATTN line
-    sbr r16, (1<<COM_IRQ_BIT_ATTN)
-    outr COM_IRQ_ADDR_ATTN, r16
+    mUartBitbangSetupInt0
   .else
-    sbi COM_IRQ_ADDR_ATTN, COM_IRQ_BIT_ATTN ; enable pin change irq for ATTN line
-    in r16, GIMSK                           ; enable pin change irq PCIE0 or PCIE1
-    ori r16, (1<<COM_IRQ_GIMSK_ATTN)
-    out GIMSK, R16
-    ldi r16, (1<<COM_IRQ_GIFR_ATTN)         ; clear pending irq by writing 1 to ATTN bit
-    out GIFR, r16
+    mUartBitbangSetupPci
   .endif
 .else
-  sbi COM_IRQ_ADDR_ATTN, COM_IRQ_BIT_ATTN ; enable pin change irq for ATTN line
-  in r16, GIMSK                           ; enable pin change irq PCIE0 or PCIE1
-  ori r16, (1<<COM_IRQ_GIMSK_ATTN)
-  out GIMSK, R16
-  ldi r16, (1<<COM_IRQ_GIFR_ATTN)         ; clear pending irq by writing 1 to ATTN bit
-  out GIFR, r16
+  mUartBitbangSetupPci
 .endif
 
 #if 0