diff --git a/lark1s/lark1s.h b/lark1s/lark1s.h
index c3cd6cc..4613207 100644
--- a/lark1s/lark1s.h
+++ b/lark1s/lark1s.h
@@ -12,8 +12,7 @@
 #define LARK1S_PARSE_CALI_REG_ERROR            (6)
 
 #define LARK1S_CALI_ZERO                       (0xFFFE)
-#define LARK1S_CALI_SPAN                       (0xFFFD)
-#define LARK1S_CALI_ZERO_SPAN                  (0xFFFC)
+#define LARK1S_CALI_SPAN                       (0xFFFC)
 
 struct lark1s_gas_info_s {
     uint32_t gas_id;