diff --git a/spicode.s65 b/spicode.s65
index c1b54f9..ba1bb66 100644
--- a/spicode.s65
+++ b/spicode.s65
@@ -1,12 +1,13 @@
 .include "system.h65"
 .include "lcd.h65"
 .include "math.h65"
+.include "keypad.h65"
 .import home:absolute
 .segment "SPI"
 .export CODE_START
 
-Export 
 CODE_START:
+.assert * = $5000, error, "SPI Code not at $5000"
     lda '$'
     jsr lcd::print_char
     lda #<TEST_FMT
@@ -25,45 +26,17 @@ CODE_START:
     sta ARG6
     jsr strf
     Print TEST_OUT
-@spiloop:
-    bbs4 ASDA,dasdZQ
-    lda IO1 + IO::RA
-    lda IO2 + IO::RA
-    jeq @spiloop
-    bge @spiloop
-    nop
-    bra @spiloop
-    bro @spiloop
-    jmp home
-    lda €asdaasd
-    lda €$ff
-    lds €asda
+    stz kp::_DEBUG_VAL
+@loop:
+    lda kp::_DEBUG_VAL
+    jeq home
+    bra @loop
 
-    lds #($ff | asd)
-    lda #'c'
-    lda #(jk:)
-
-
-; TODO allocate zp memory
 fmt_idx = $30
 out_idx = $31
-;********************************************************************************
-; @function Format a string
-; @details
-;   If there is no value to be read, the Pz will be set
-;   Formats:
-;   - u: unsigned decimal integer (1 byte)
-;   - U: unsigned decimal integer (2 bytes)
-; @param ARG0-1: Format string address
-; @param ARG2-3: Output string address
-; @param ARG4+:  Additional parameters
-; @returns 
-; @modifies: A, Y
-;********************************************************************************
 .proc strf
     stz out_idx
     stz fmt_idx
-    ldy #0  ; position in string
     ldx #0  ; index of format args
 @loop:
     ldy fmt_idx
@@ -81,7 +54,7 @@ out_idx = $31
 @percent:  ; check for format in next position
         iny
         sty fmt_idx
-        lda (ARG0),y
+        lda (ARG0),y  ; next char
         beq @null
         ; formats
         cmp #'x'
@@ -124,26 +97,68 @@ out_idx = $31
 ; @param A: Number to convert
 ; @returns A: Most significant digit
 ; @returns X: Least significant digit
-; @modifies X,Y,A
+; @modifies A,X,Y
 ;********************************************************************************
 .proc int8_to_hex_str
     pha
     and #%00001111
     tay
-    ldx HEX_CHARS,y
+    ldx HEX_CHARS_UPPER,y
     pla
     div A,16
     and #%00001111
     tay
-    lda HEX_CHARS,y
+    lda HEX_CHARS_UPPER,y
     rts
 .endproc
-    
-    
 
 
-HEX_CHARS: .byte "0123456789ABCDEF"
+;********************************************************************************
+; @function Convert any int into hex
+; @param ARG2-3: Address of output string
+; @param Y: Offset onto output string
+; @param A: Number of digits to convert
+; @param X: Offset onto ARG4 = start of int (big endian)
+; @returns Y: New offset onto output string
+; @returns A: 0
+; @returns X: Offset onto ARG4 = past the end of number
+; @modifies X,Y,A
+;********************************************************************************
+.proc int_to_hex_str
+    cmp #0
+@loop:
+    beq @rts  ; check done
+    ; load next byte
+    pha
+        lda ARG4,x
+        inx
+        phx
+            pha  ; copy byte
+                div A,16  ; get first 4 bits = first digit
+                and #%00001111
+                phy
+                    tay
+                    lda HEX_CHARS_LOWER,y
+                ply
+                sta (ARG2),y 
+                iny
+            pla  ; get copy 
+            and #%00001111  ; lower 4 bits = second digit
+            phy
+                tay
+                lda HEX_CHARS_LOWER,y
+            ply
+            sta (ARG2),y 
+            iny
+        plx
+    pla
+    dec
+@rts:
+    rts
+.endproc
+
 
 TEST_FMT: .asciiz "%x -> %x -> %x:)"
 TEST_OUT: .asciiz "TESTOUT"
-
+HEX_CHARS_UPPER:    .byte "0123456789ABCDEF"
+HEX_CHARS_LOWER:    .byte "0123456789abcdef"