diff --git a/sw/main.c b/sw/main.c
index d20d3e0..c7a5217 100644
--- a/sw/main.c
+++ b/sw/main.c
@@ -3,10 +3,8 @@
 #include "sevenseg.h"
 
 int main() {
-    //hex_enable(0xff);
-    hex_set_8(0xb5, 0);
-    hex_set_8(0x00, 1);
-    hex_set_8(0xb0, 2);
+    hex_enable(0x3f);
+    hex_set_24(0xabcdef);
     while(1);
     return 0;
 }
diff --git a/sw/sevenseg.s b/sw/sevenseg.s
index 3305c2e..e915d59 100644
--- a/sw/sevenseg.s
+++ b/sw/sevenseg.s
@@ -1,5 +1,7 @@
 .include "io.inc65"
 
+.importzp sp, sreg
+
 .export _hex_set_8
 .export _hex_set_16
 .export _hex_set_24
@@ -34,8 +36,14 @@ _hex_set_16:
         lda #$0
         rts
 
+; @in A/X/sreg: val
+; @out A: 0 for success, 1 for failure
+; Sets the 3 pairs of hex digits for a 24 bit value
 _hex_set_24:
-        lda #$1
+        sta SEVEN_SEG
+        stx SEVEN_SEG+1
+        lda sreg
+        sta SEVEN_SEG+2
         rts
 
 ; @in A: mask