diff -r f0fdcce9874b -r f09b0623a2c1 master/fmmu_config.h
--- a/master/fmmu_config.h	Thu Mar 26 17:41:57 2015 -0400
+++ b/master/fmmu_config.h	Thu Apr 02 16:49:36 2015 -0400
@@ -59,6 +59,15 @@
 void ec_fmmu_config_init(ec_fmmu_config_t *, ec_slave_config_t *,
         ec_domain_t *, uint8_t, ec_direction_t);
 
+/**
+ * @param fmmu EtherCAT FMMU configuration.
+ * @param logical_domain_offset Logical offset address 
+        relative to domain->logical_base_address.
+ * @param data_size Covered PDO size.
+*/        
+void ec_fmmu_set_domain_offset_size(ec_fmmu_config_t *fmmu, 
+        uint32_t logical_domain_offset, unsigned data_size);
+
 void ec_fmmu_config_page(const ec_fmmu_config_t *, const ec_sync_t *,
         uint8_t *);