diff --git a/applications/xmc4300_slavedemo/ecat_options.h b/applications/xmc4300_slavedemo/ecat_options.h
index 0181a61..7bf98ff 100644
--- a/applications/xmc4300_slavedemo/ecat_options.h
+++ b/applications/xmc4300_slavedemo/ecat_options.h
@@ -38,7 +38,7 @@
 #define MAX_RXPDO_SIZE   42
 #define MAX_TXPDO_SIZE   42
 
-#define MAX_MAPPINGS_SM2 1
-#define MAX_MAPPINGS_SM3 2
+#define MAX_MAPPINGS_SM2 0
+#define MAX_MAPPINGS_SM3 0
 
 #endif /* __ECAT_OPTIONS_H__ */
diff --git a/applications/xmc4300_slavedemo/main.c b/applications/xmc4300_slavedemo/main.c
index e75c4b5..05e4d0f 100644
--- a/applications/xmc4300_slavedemo/main.c
+++ b/applications/xmc4300_slavedemo/main.c
@@ -24,6 +24,9 @@ _Rbuffer    Rb;
 _Wbuffer    Wb;
 _Cbuffer    Cb;
 
+uint8_t * rxpdo = (uint8_t *)&Wb.LED;
+uint8_t * txpdo = (uint8_t *)&Rb.button;
+
 uint32_t encoder_scale;
 uint32_t encoder_scale_mirror;
 
diff --git a/applications/xmc4300_slavedemo/utypes.h b/applications/xmc4300_slavedemo/utypes.h
index c9326d5..2931a91 100644
--- a/applications/xmc4300_slavedemo/utypes.h
+++ b/applications/xmc4300_slavedemo/utypes.h
@@ -16,21 +16,27 @@
 
 #include <cc.h>
 
+CC_PACKED_BEGIN
 typedef struct
 {
    uint8_t state;
    uint8_t button;
    uint32_t encoder;
-} _Rbuffer;
+}CC_PACKED _Rbuffer;
+CC_PACKED_END
 
+CC_PACKED_BEGIN
 typedef struct
 {
    uint8_t LED;
-} _Wbuffer;
+}CC_PACKED _Wbuffer;
+CC_PACKED_END
 
+CC_PACKED_BEGIN
 typedef struct
 {
    uint32_t reset_counter;
-} _Cbuffer;
+}CC_PACKED _Cbuffer;
+CC_PACKED_END
 
 #endif
diff --git a/soes/ecat_slv.c b/soes/ecat_slv.c
index 7a9230b..c28055d 100644
--- a/soes/ecat_slv.c
+++ b/soes/ecat_slv.c
@@ -21,8 +21,18 @@ _ESCvar     ESCvar;
 
 /* Private variables */
 static volatile int watchdog;
+
+#if MAX_MAPPINGS_SM2 > 0
 static uint8_t rxpdo[MAX_RXPDO_SIZE] __attribute__((aligned (8)));
+#else
+extern uint8_t * rxpdo;
+#endif
+
+#if MAX_MAPPINGS_SM3 > 0
 static uint8_t txpdo[MAX_TXPDO_SIZE] __attribute__((aligned (8)));
+#else
+extern uint8_t * txpdo;
+#endif
 
 /** Function to pre-qualify the incoming SDO download.
  *
@@ -98,7 +108,10 @@ void TXPDO_update (void)
    }
    else
    {
-      COE_pdoPack (txpdo, ESCvar.sm3mappings, SMmap3);
+      if (MAX_MAPPINGS_SM3 > 0)
+      {
+         COE_pdoPack (txpdo, ESCvar.sm3mappings, SMmap3);
+      }
       ESC_write (ESC_SM3_sma, txpdo, ESCvar.ESC_SM3_sml);
    }
 }
@@ -114,7 +127,10 @@ void RXPDO_update (void)
    else
    {
       ESC_read (ESC_SM2_sma, rxpdo, ESCvar.ESC_SM2_sml);
-      COE_pdoUnpack (rxpdo, ESCvar.sm2mappings, SMmap2);
+      if (MAX_MAPPINGS_SM2 > 0)
+      {
+         COE_pdoUnpack (rxpdo, ESCvar.sm2mappings, SMmap2);
+      }
    }
 }
 
diff --git a/soes/esc_coe.c b/soes/esc_coe.c
index 3611c6d..48ed5cc 100644
--- a/soes/esc_coe.c
+++ b/soes/esc_coe.c
@@ -69,6 +69,16 @@ int32_t SDO_findobject (uint16_t index)
  * Calculate the size in Bytes of RxPDO or TxPDOs by adding the
  * objects in SyncManager SDO 1C1x.
  *
+ * A list of mapped objects is created for fast lookup of
+ * dynamically mapped process data. The max size of the list (@a
+ * max_mappings) can be set to 0 if dynamic processdata is not
+ * supported.
+ *
+ * The output variable @a nmappings is set to 0 if dynamic processdata
+ * is not supported. It is set to the number of mapped objects if
+ * dynamic processdata is supported, or -1 if the mapping was
+ * incorrect.
+
  * @param[in] index = SM index
  * @param[out] nmappings = number of mapped objects in SM, or -1 if
  *   mapping is invalid
@@ -76,7 +86,7 @@ int32_t SDO_findobject (uint16_t index)
  * @param[out] max_mappings = max number of mapped objects in SM
  * @return size of RxPDO or TxPDOs in Bytes.
  */
-uint16_t sizeOfPDO (uint16_t index, int * nmappings,_SMmap * mappings,
+uint16_t sizeOfPDO (uint16_t index, int * nmappings, _SMmap * mappings,
                     int max_mappings)
 {
    uint16_t offset = 0, hobj;
@@ -116,46 +126,72 @@ uint16_t sizeOfPDO (uint16_t index, int * nmappings,_SMmap * mappings,
             for (c = 1; c <= maxsub; c++)
             {
                uint32_t value = OBJ_VALUE_FETCH (value, objd[c]);
-               uint16_t index = value >> 16;
-               uint8_t subindex = (value >> 8) & 0xFF;
                uint8_t bitlength = value & 0xFF;
-               const _objd * mapping;
 
-               if (mapIx == max_mappings)
+               if (max_mappings > 0)
                {
-                  /* Too many mapped objects */
-                  *nmappings = -1;
-                  return 0;
-               }
+                  uint16_t index = value >> 16;
+                  uint8_t subindex = (value >> 8) & 0xFF;
+                  const _objd * mapping;
 
-               DPRINT ("%04x:%02x @ %d\n", index, subindex, offset);
-               nidx = SDO_findobject (index);
-               if (nidx >= 0)
-               {
-                  int16_t nsub;
-
-                  nsub = SDO_findsubindex (nidx, subindex);
-                  if (nsub < 0)
+                  if (mapIx == max_mappings)
                   {
-                     mapping = NULL;
+                     /* Too many mapped objects */
+                     *nmappings = -1;
+                     return 0;
                   }
 
-                  mapping = &SDOobjects[nidx].objdesc[nsub];
-               }
-               else
-               {
-                  mapping = NULL;
-               }
+                  DPRINT ("%04x:%02x @ %d\n", index, subindex, offset);
 
-               mappings[mapIx].obj = mapping;
-               mappings[mapIx++].offset = offset;
+                  if (index == 0 && subindex == 0)
+                  {
+                     /* Padding element */
+                     mapping = NULL;
+                  }
+                  else
+                  {
+                     nidx = SDO_findobject (index);
+                     if (nidx >= 0)
+                     {
+                        int16_t nsub;
+
+                        nsub = SDO_findsubindex (nidx, subindex);
+                        if (nsub < 0)
+                        {
+                           /* Mapped subindex does not exist */
+                           *nmappings = -1;
+                           return 0;
+                        }
+
+                        mapping = &SDOobjects[nidx].objdesc[nsub];
+                     }
+                     else
+                     {
+                        /* Mapped index does not exist */
+                        *nmappings = -1;
+                        return 0;
+                     }
+                  }
+
+                  mappings[mapIx].obj = mapping;
+                  mappings[mapIx++].offset = offset;
+               }
 
                offset += bitlength;
             }
          }
       }
    }
-   *nmappings = mapIx;
+
+   if (max_mappings > 0)
+   {
+      *nmappings = mapIx;
+   }
+   else
+   {
+      *nmappings = 0;
+   }
+
    return BITS2BYTES (offset);
 }
 
diff --git a/soes/options.h b/soes/options.h
index 488ce19..1f3db05 100644
--- a/soes/options.h
+++ b/soes/options.h
@@ -119,26 +119,29 @@
 #define SM3_act          1
 #endif
 
-/* Max processdata size (outputs) */
-#ifndef MAX_RXPDO_SIZE
-#define MAX_RXPDO_SIZE   128
-#endif
-
-/* Max processdata size (inputs) */
-#ifndef MAX_TXPDO_SIZE
-#define MAX_TXPDO_SIZE   128
-#endif
-
-/* Max number of mapped objects in SM2 */
+/* Max number of dynamically mapped objects in SM2. May be 0 to
+   disable dynamic processdata. */
 #ifndef MAX_MAPPINGS_SM2
 #define MAX_MAPPINGS_SM2 16
 #endif
 
-/* Max number of mapped objects in SM3 */
+/* Max number of dynamically mapped objects in SM3. May be 0 to
+   disable dynamic processdata. */
 #ifndef MAX_MAPPINGS_SM3
 #define MAX_MAPPINGS_SM3 16
 #endif
 
-/* _Static_assert (SM2_sma + 3 * MAX_INPUT_SIZE < SM3_sma); */
+/* Max processdata size (outputs). Only used if MAX_MAPPINGS_SM2 is
+   non-zero. */
+#ifndef MAX_RXPDO_SIZE
+#define MAX_RXPDO_SIZE   128
+#endif
+
+/* Max processdata size (inputs). Only used if MAX_MAPPINGS_SM3 is
+   non-zero. */
+#ifndef MAX_TXPDO_SIZE
+#define MAX_TXPDO_SIZE   128
+#endif
+
 
 #endif /* __options__ */