diff --git a/main.s65 b/main.s65
index 2bac2f6..bde877d 100644
--- a/main.s65
+++ b/main.s65
@@ -1,5 +1,5 @@
-.segment "CODE"
-.include "system/system.h65"
+.include "system/system.s65"
+.code
 
 .macro DEBUG_LED_OFF nr
     lda IO1 + IO::RA
@@ -44,6 +44,7 @@ SPI_IO = IO2
 ;********************************************************************************    
 ; Interrupts
 ;********************************************************************************    
+.code
 nmi:
     lda #'%'
     jsr lcd_char
@@ -145,11 +146,11 @@ print_2:
     PrintSlow message_2,10
     jmp home
 
-.segment "RODATA"
+.rodata
 message_1: .asciiz "   Powered by   ......6502......      ****      www.quintern.xyz"
 message_2:
-    .byte   "   Hallo        "
-    .byte   "     Clara      "
+    .byte   "   Hello        "
+    .byte   "     there      "
     .byte   "       <3       "
     .asciiz "================"
 message_menu: 
@@ -163,7 +164,6 @@ str_irq:
 str_irq_unknown:
     .asciiz "Unknown IRQ src!"
 
-.segment "CODE"
 ;********************************************************************************
 ; reset vector
 ;********************************************************************************
diff --git a/programs/printer.s65 b/programs/printer.s65
index 25aa2ec..1b90cb5 100644
--- a/programs/printer.s65
+++ b/programs/printer.s65
@@ -3,7 +3,7 @@
 ;********************************************************************************
 .ifndef INCLUDE_PRINTER
 INCLUDE_PRINTER = 1
-
+.code
 printer:
     jsr lcd_clear
 @printer_loop:
diff --git a/programs/sleep.s65 b/programs/sleep.s65
index 5a78336..f274ac6 100644
--- a/programs/sleep.s65
+++ b/programs/sleep.s65
@@ -1,5 +1,6 @@
 .ifndef INCLUDE_SLEEP
 INCLUDE_SLEEP = 1
+.code
 ;********************************************************************************
 ; @macro Sleep
 ; @param time_cs: Time to sleep in centiseconds (10^-2s = 10ms)
@@ -19,15 +20,16 @@ INCLUDE_SLEEP = 1
 ; @details
 ;   Interrupts might change the actual time to finish
 ;   To be exact, time_cs is in units of 0.010244s
+; @modifies: ARG2
 ;********************************************************************************
 .proc sleep
-VAR_1 = 0
-    stz VAR_1
+_VAR_1 = ARG2
+    stz _VAR_1
 @loop:
     .repeat 17
     nop             ; 2 - i
     .endrepeat
-    inc VAR_1       ; 3 - zp
+    inc _VAR_1       ; 3 - zp
     bne @loop       ; 2/3 - r (2 if not taken, but here most of the time its 3)
     ; reaching this takes 256 * (X * 2(nop) + 3(inc) + 3(bne)) - 1(last bne) cycles
     ; with X = 17: T1 = (256×(17×2 + 3 +3) − 1) × (1/1MHz) = 0,010 239 s
diff --git a/system/buffer.s65 b/system/buffer.s65
index 599dc30..68468e2 100644
--- a/system/buffer.s65
+++ b/system/buffer.s65
@@ -7,10 +7,11 @@
 ;   The RBUF_NAME variable must be defined, the functions will then be exported
 ;   as rb_<RBUF_NAME>_<function> where <function> = init, read or write
 ; @requires
-;   RBUF_MEM_START: Start address of ringbuffer memory space
-;   RBUF_MEM_END: End address of ringbuffer memory space
+;   RBUF_MEM_START: First address of ringbuffer memory space
+;   RBUF_MEM_END: Last address of ringbuffer memory space
 ;   RBUF_NAME: Name of the ringbuffer
 ;********************************************************************************
+.code
 
 .ifndef RBUF_MEM_START
     .fatal "RBUF_MEM_START not defined"
diff --git a/system/keypad.s65 b/system/keypad.s65
index 67f0b18..ea9d628 100644
--- a/system/keypad.s65
+++ b/system/keypad.s65
@@ -16,14 +16,17 @@ INCLUDE_KEYPAD = 1
     .fatal "KP_IO is not defined: set it to the base address of the IO chip of the Keypad"
 .endif
 
+.zeropage
+_KP_COLUMN:         .res 1  ; for storing stuff
 
-RBUF_MEM_START = $200
-RBUF_MEM_END = $208
+.bss  ; reserve space or ringbuffer
+KP_BUF_SIZE = 10
+RBUF_MEM_START: .res KP_BUF_SIZE
+RBUF_MEM_END = RBUF_MEM_START + KP_BUF_SIZE - 1   
 .define RBUF_NAME "keypad"
 .include "buffer.s65"
 
-KB_VAR      = $05  ; any free zp address
-
+.code
 .proc kp_init
     ; todo remove later and test
     lda #$ff
@@ -74,23 +77,23 @@ KB_VAR      = $05  ; any free zp address
 @kp_read_column:
     sta KP_IO+IO::RB
     lda KP_IO+IO::RB
-    sta KB_VAR  ; store result in zeropage so that bbr can be used
-    bbr4 KB_VAR,@kp_write
+    sta _KP_COLUMN  ; store result in zeropage so that bbr can be used
+    bbr4 _KP_COLUMN,@kp_write
     inx
-    bbr5 KB_VAR,@kp_write
+    bbr5 _KP_COLUMN,@kp_write
     inx
-    bbr6 KB_VAR,@kp_write
+    bbr6 _KP_COLUMN,@kp_write
     inx
-    bbr7 KB_VAR,@kp_write
+    bbr7 _KP_COLUMN,@kp_write
     rts
 @kp_write:
-    lda kp_VALUES,x
+    lda _KP_VALUES,x
     jsr rb_keypad_write
     rts
 .endproc
 
-.segment "RODATA"
-kp_VALUES:
+.rodata
+_KP_VALUES:
     ; TODO change to literal
     .byte "123A", "456B", "789C", "*0#D" 
 .endif
diff --git a/system/spi.s65 b/system/spi.s65
index e634bc8..60df03a 100644
--- a/system/spi.s65
+++ b/system/spi.s65
@@ -5,17 +5,18 @@
 ; @depends IO-W65C22N
 ;********************************************************************************
 
-.include "system/system.h65"
+.include "system/system.s65"
 
 .ifndef INCLUDE_SPI
 INCLUDE_SPI = 1
-.segment "CODE"
-
-SPI_CODE_START = $3000
-SPI_PAGES_WRITTEN = $2fff
-SPI_BYTES_WRITTEN = $2ffe
 
 
+.bss
+SPI_PAGES_WRITTEN:  .res 1
+SPI_BYTES_WRITTEN:  .res 1
+SPI_CODE_START:     .res $1000
+
+.code
 .struct SPI_P_Pins
     ; VIA addresses
     DDR_a   .word   ; address of the data direction register