diff --git a/firmware/libcommon/include/iso7816_fidi.h b/firmware/libcommon/include/iso7816_fidi.h
index e4690a5..3b4b451 100644
--- a/firmware/libcommon/include/iso7816_fidi.h
+++ b/firmware/libcommon/include/iso7816_fidi.h
@@ -2,5 +2,11 @@
 
 #include <stdint.h>
 
+/* Table 7 of ISO 7816-3:2006 */
+extern const uint16_t fi_table[];
+
+/* Table 8 from ISO 7816-3:2006 */
+extern const uint8_t di_table[];
+
 /* compute the F/D ratio based on Fi and Di values */
 int compute_fidi_ratio(uint8_t fi, uint8_t di);