Added new MS/TP skip data state.

Added ring buffer for incoming PDU to fix WhoIs followed by ReadProperty situation.

bacnet-stack/ports/bdk-atxx4-mstp/Makefile

@@ -88,6 +88,7 @@ DEMOSRC = $(BACNET_DEMO)/handler/txbuf.c \
 # core BACnet stack files
 CORESRC =  \
 	$(BACNET_CORE)/fifo.c \
+	$(BACNET_CORE)/ringbuf.c \
 	$(BACNET_CORE)/memcopy.c \
 	$(BACNET_CORE)/crc.c \
 	$(BACNET_CORE)/apdu.c \

bacnet-stack/ports/bdk-atxx4-mstp/bacnet.aps

@@ -1 +1 @@
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+<AVRStudio><MANAGEMENT><ProjectName>bacnet</ProjectName><Created>29-Apr-2009 08:16:53</Created><LastEdit>12-Sep-2010 23:23:02</LastEdit><ICON>241</ICON><ProjectType>0</ProjectType><Created>29-Apr-2009 08:16:53</Created><Version>4</Version><Build>4, 15, 0, 623</Build><ProjectTypeName>AVR GCC</ProjectTypeName></MANAGEMENT><CODE_CREATION><ObjectFile>bacnet.elf</ObjectFile><EntryFile></EntryFile><SaveFolder>D:\code\bacnet-stack\ports\bdk-atxx4-mstp\</SaveFolder></CODE_CREATION><DEBUG_TARGET><CURRENT_TARGET>JTAGICE mkII</CURRENT_TARGET><CURRENT_PART>ATmega644P.xml</CURRENT_PART><BREAKPOINTS></BREAKPOINTS><IO_EXPAND><HIDE>false</HIDE></IO_EXPAND><REGISTERNAMES><Register>R00</Register><Register>R01</Register><Register>R02</Register><Register>R03</Register><Register>R04</Register><Register>R05</Register><Register>R06</Register><Register>R07</Register><Register>R08</Register><Register>R09</Register><Register>R10</Register><Register>R11</Register><Register>R12</Register><Register>R13</Register><Register>R14</Register><Register>R15</Register><Register>R16</Register><Register>R17</Register><Register>R18</Register><Register>R19</Register><Register>R20</Register><Register>R21</Register><Register>R22</Register><Register>R23</Register><Register>R24</Register><Register>R25</Register><Register>R26</Register><Register>R27</Register><Register>R28</Register><Register>R29</Register><Register>R30</Register><Register>R31</Register></REGISTERNAMES><COM>Auto</COM><COMType>0</COMType><WATCHNUM>0</WATCHNUM><WATCHNAMES><Pane0></Pane0><Pane1></Pane1><Pane2></Pane2><Pane3></Pane3></WATCHNAMES><BreakOnTrcaeFull>0</BreakOnTrcaeFull></DEBUG_TARGET><Debugger><modules><module></module></modules><Triggers></Triggers></Debugger><AVRGCCPLUGIN><FILES><SOURCEFILE>main.c</SOURCEFILE><SOURCEFILE>timer2.c</SOURCEFILE><SOURCEFILE>eeprom.c</SOURCEFILE><SOURCEFILE>init.c</SOURCEFILE><SOURCEFILE>input.c</SOURCEFILE><SOURCEFILE>led.c</SOURCEFILE><SOURCEFILE>rs485.c</SOURCEFILE><SOURCEFILE>seeprom.c</SOURCEFILE><SOURCEFILE>serial.c</SOURCEFILE><SOURCEFILE>stack.c</SOURCEFILE><SOURCEFILE>dlmstp.c</SOURCEFILE><SOURCEFILE>bo.c</SOURCEFILE><SOURCEFILE>bi.c</SOURCEFILE><SOURCEFILE>ai.c</SOURCEFILE><SOURCEFILE>device.c</SOURCEFILE><HEADERFILE>timer.h</HEADERFILE><HEADERFILE>eeprom.h</HEADERFILE><HEADERFILE>hardware.h</HEADERFILE><HEADERFILE>iar2gcc.h</HEADERFILE><HEADERFILE>init.h</HEADERFILE><HEADERFILE>input.h</HEADERFILE><HEADERFILE>led.h</HEADERFILE><HEADERFILE>nvdata.h</HEADERFILE><HEADERFILE>rs485.h</HEADERFILE><HEADERFILE>seeprom.h</HEADERFILE><HEADERFILE>serial.h</HEADERFILE><OTHERFILE>Makefile</OTHERFILE></FILES><CONFIGS><CONFIG><NAME>default</NAME><USESEXTERNALMAKEFILE>YES</USESEXTERNALMAKEFILE><EXTERNALMAKEFILE>Makefile</EXTERNALMAKEFILE><PART>atmega644p</PART><HEX>1</HEX><LIST>1</LIST><MAP>1</MAP><OUTPUTFILENAME>bacnet.elf</OUTPUTFILENAME><OUTPUTDIR>default\</OUTPUTDIR><ISDIRTY>1</ISDIRTY><OPTIONS/><INCDIRS/><LIBDIRS/><LIBS/><LINKOBJECTS/><OPTIONSFORALL>-Wall -gdwarf-2 -std=gnu99 -Os -funsigned-char -funsigned-bitfields -fpack-struct -fshort-enums</OPTIONSFORALL><LINKEROPTIONS></LINKEROPTIONS><SEGMENTS/></CONFIG></CONFIGS><LASTCONFIG>default</LASTCONFIG><USES_WINAVR>1</USES_WINAVR><GCC_LOC>C:\WinAVR-20100110\bin\avr-gcc.exe</GCC_LOC><MAKE_LOC>C:\WinAVR-20100110\utils\bin\make.exe</MAKE_LOC></AVRGCCPLUGIN><IOView><usergroups/><sort sorted="0" column="0" ordername="0" orderaddress="0" ordergroup="0"/></IOView><Files><File00000><FileId>00000</FileId><FileName>main.c</FileName><Status>259</Status></File00000><File00001><FileId>00001</FileId><FileName>Makefile</FileName><Status>1</Status></File00001></Files><Events><Bookmarks></Bookmarks></Events><Trace><Filters></Filters></Trace></AVRStudio>

bacnet-stack/ports/bdk-atxx4-mstp/bacnet.ewp

@@ -2041,6 +2041,9 @@
     <file>
       <name>$PROJ_DIR$\..\..\src\reject.c</name>
     </file>
+    <file>
+      <name>$PROJ_DIR$\..\..\src\ringbuf.c</name>
+    </file>
     <file>
       <name>$PROJ_DIR$\..\..\src\rp.c</name>
     </file>

bacnet-stack/ports/bdk-atxx4-mstp/dlmstp.c

@@ -38,12 +38,14 @@
 #include <string.h>
 #include "bacdef.h"
 #include "dlmstp.h"
+#include "mstpdef.h"
 #include "rs485.h"
 #include "crc.h"
 #include "npdu.h"
 #include "bits.h"
 #include "bytes.h"
 #include "bacaddr.h"
+#include "ringbuf.h"
 #include "timer.h"
 #include "eeprom.h"
 #include "nvdata.h"
@@ -53,52 +55,6 @@
     Only one MS/TP datalink layer
 */
 
-/*  The value 255 is used to denote broadcast when used as a */
-/* destination address but is not allowed as a value for a station. */
-/* Station addresses for master nodes can be 0-127.  */
-/* Station addresses for slave nodes can be 127-254.  */
-#define MSTP_BROADCAST_ADDRESS 255
-
-/* MS/TP Frame Type */
-/* Frame Types 8 through 127 are reserved by ASHRAE. */
-#define FRAME_TYPE_TOKEN 0
-#define FRAME_TYPE_POLL_FOR_MASTER 1
-#define FRAME_TYPE_REPLY_TO_POLL_FOR_MASTER 2
-#define FRAME_TYPE_TEST_REQUEST 3
-#define FRAME_TYPE_TEST_RESPONSE 4
-#define FRAME_TYPE_BACNET_DATA_EXPECTING_REPLY 5
-#define FRAME_TYPE_BACNET_DATA_NOT_EXPECTING_REPLY 6
-#define FRAME_TYPE_REPLY_POSTPONED 7
-/* Frame Types 128 through 255: Proprietary Frames */
-/* These frames are available to vendors as proprietary (non-BACnet) frames. */
-/* The first two octets of the Data field shall specify the unique vendor */
-/* identification code, most significant octet first, for the type of */
-/* vendor-proprietary frame to be conveyed. The length of the data portion */
-/* of a Proprietary frame shall be in the range of 2 to 501 octets. */
-#define FRAME_TYPE_PROPRIETARY_MIN 128
-#define FRAME_TYPE_PROPRIETARY_MAX 255
-
-/* receive FSM states */
-typedef enum {
-    MSTP_RECEIVE_STATE_IDLE = 0,
-    MSTP_RECEIVE_STATE_PREAMBLE = 1,
-    MSTP_RECEIVE_STATE_HEADER = 2,
-    MSTP_RECEIVE_STATE_DATA = 3
-} MSTP_RECEIVE_STATE;
-
-/* master node FSM states */
-typedef enum {
-    MSTP_MASTER_STATE_INITIALIZE = 0,
-    MSTP_MASTER_STATE_IDLE = 1,
-    MSTP_MASTER_STATE_USE_TOKEN = 2,
-    MSTP_MASTER_STATE_WAIT_FOR_REPLY = 3,
-    MSTP_MASTER_STATE_DONE_WITH_TOKEN = 4,
-    MSTP_MASTER_STATE_PASS_TOKEN = 5,
-    MSTP_MASTER_STATE_NO_TOKEN = 6,
-    MSTP_MASTER_STATE_POLL_FOR_MASTER = 7,
-    MSTP_MASTER_STATE_ANSWER_DATA_REQUEST = 8
-} MSTP_MASTER_STATE;
-
 /* The state of the Receive State Machine */
 static MSTP_RECEIVE_STATE Receive_State;
 /* When a master node is powered up or reset, */
@@ -114,22 +70,18 @@ static struct mstp_flag_t {
     /* if a valid frame is received.  */
     /* Set to FALSE by the main state machine. */
     unsigned ReceivedValidFrame:1;
+    /* set to TRUE when we get a frame not for us */
+    unsigned ReceivedValidFrameNotForUs:1;
     /* A Boolean flag set to TRUE by the master machine if this node is the */
     /* only known master node. */
     unsigned SoleMaster:1;
-    /* A Boolean flag set TRUE by the datalink transmit if a
-       frame is pending */
-    unsigned TransmitPacketPending:1;
-    /* A Boolean flag set TRUE by the datalink transmit if a
-       pending packet is DataExpectingReply */
-    unsigned TransmitPacketDER:1;
     /* A Boolean flag set TRUE by the datalink if a
        packet has been received, but not processed. */
     unsigned ReceivePacketPending:1;
 } MSTP_Flag;
 
 /* Used to store the data length of a received frame. */
-static uint16_t DataLength;
+static uint32_t DataLength;
 /* Used to store the destination address of a received frame. */
 static uint8_t DestinationAddress;
 /* Used to count the number of received octets or errors. */
@@ -160,23 +112,13 @@ static uint8_t This_Station;
 /* nodes. This may be used to allocate more or less of the available link */
 /* bandwidth to particular nodes. If Max_Info_Frames is not writable in a */
 /* node, its value shall be 1. */
-#define Nmax_info_frames 1
+static uint8_t Nmax_info_frames = 1;
 /* This parameter represents the value of the Max_Master property of the */
 /* node's Device object. The value of Max_Master specifies the highest */
 /* allowable address for master nodes. The value of Max_Master shall be */
 /* less than or equal to 127. If Max_Master is not writable in a node, */
 /* its value shall be 127. */
 static uint8_t Nmax_master = 127;
-/* An array of octets, used to store octets for transmitting */
-/* OutputBuffer is indexed from 0 to OutputBufferSize-1. */
-/* The MAX_PDU size of a frame is MAX_APDU + MAX_NPDU octets. */
-/* FIXME: assign this to an actual array of bytes! */
-/* Note: the buffer is designed as a pointer since some compilers
-   and microcontroller architectures have limits as to places to
-   hold contiguous memory. */
-static uint8_t *TransmitPacket;
-static uint16_t TransmitPacketLen;
-static uint8_t TransmitPacketDest;
 
 /* The time without a DataAvailable or ReceiveError event before declaration */
 /* of loss of token: 500 milliseconds. */
@@ -239,6 +181,20 @@ static uint8_t TransmitPacketDest;
 /* we need to be able to increment without rolling over */
 #define INCREMENT_AND_LIMIT_UINT8(x) {if (x < 0xFF) x++;}
 
+/* data structure for MS/TP PDU Queue */
+struct mstp_pdu_packet {
+    bool data_expecting_reply;
+    uint8_t destination_mac;
+    uint16_t length;
+    uint8_t buffer[MAX_MPDU];
+};
+/* count must be a power of 2 for ringbuf library */
+#ifndef MSTP_PDU_PACKET_COUNT
+#define MSTP_PDU_PACKET_COUNT 2
+#endif
+static struct mstp_pdu_packet PDU_Buffer[MSTP_PDU_PACKET_COUNT];
+static RING_BUFFER PDU_Queue;
+
 bool dlmstp_init(
     char *ifname)
 {
@@ -248,6 +204,11 @@ bool dlmstp_init(
     if (Nmax_master > 127) {
         Nmax_master = 127;
     }
+    Ringbuf_Init(
+        &PDU_Queue,
+        (uint8_t *)&PDU_Buffer,
+        sizeof(struct mstp_pdu_packet),
+        MSTP_PDU_PACKET_COUNT);
 
     return true;
 }
@@ -572,37 +533,38 @@ static void MSTP_Receive_Frame_FSM(
                         /* wait for the start of the next frame. */
                         Receive_State = MSTP_RECEIVE_STATE_IDLE;
                     } else {
-                        /* Note: proposed change to BACnet MSTP state machine!
+                        if (DataLength == 0) {
-                           If we don't decode data that is not for us, we could
+                            /* NoData */
-                           get confused about the start if the Preamble 55 FF
+                            if ((DestinationAddress == This_Station) ||
-                           is part of the data. */
+                                (DestinationAddress ==
-                        if ((DataLength) && (DataLength <= InputBufferSize)) {
+                                    MSTP_BROADCAST_ADDRESS)) {
-                            /* Data */
+                                /* ForUs */
-                            Index = 0;
+                                /* indicate that a frame with
-                            DataCRC = 0xFFFF;
+                                   no data has been received */
-                            /* receive the data portion of the frame. */
+                                MSTP_Flag.ReceivedValidFrame = true;
-                            Receive_State = MSTP_RECEIVE_STATE_DATA;
-                        } else {
-                            if (DataLength == 0) {
-                                /* NoData */
-                                if ((DestinationAddress == This_Station) ||
-                                    (DestinationAddress ==
-                                        MSTP_BROADCAST_ADDRESS)) {
-                                    /* ForUs */
-                                    /* indicate that a frame with
-                                       no data has been received */
-                                    MSTP_Flag.ReceivedValidFrame = true;
-                                } else {
-                                    /* NotForUs - drop */
-                                }
                             } else {
-                                /* FrameTooLong */
+                                /* NotForUs */
-                                /* indicate that a frame with an illegal or  */
+                                MSTP_Flag.ReceivedValidFrameNotForUs = true;
-                                /* unacceptable data length has been received */
-                                MSTP_Flag.ReceivedInvalidFrame = true;
                             }
                             /* wait for the start of the next frame. */
                             Receive_State = MSTP_RECEIVE_STATE_IDLE;
+                        } else {
+                            /* receive the data portion of the frame. */
+                            if ((DestinationAddress == This_Station) ||
+                                (DestinationAddress == MSTP_BROADCAST_ADDRESS)) {
+                                if (DataLength <= InputBufferSize) {
+                                    /* Data */
+                                    Receive_State = MSTP_RECEIVE_STATE_DATA;
+                            } else {
+                                /* FrameTooLong */
+                                    Receive_State = MSTP_RECEIVE_STATE_SKIP_DATA;
+                            }
+                            } else {
+                                /* NotForUs */
+                                Receive_State = MSTP_RECEIVE_STATE_SKIP_DATA;
+                            }
+                            Index = 0;
+                            DataCRC = 0xFFFF;
                         }
                     }
                 } else {
@@ -615,6 +577,7 @@ static void MSTP_Receive_Frame_FSM(
             }
             break;
         case MSTP_RECEIVE_STATE_DATA:
+        case MSTP_RECEIVE_STATE_SKIP_DATA:
             /* In the DATA state, the node waits
                for the data portion of a frame. */
             if (rs485_silence_time_elapsed(Tframe_abort)) {
@@ -639,7 +602,9 @@ static void MSTP_Receive_Frame_FSM(
                 if (Index < DataLength) {
                     /* DataOctet */
                     DataCRC = CRC_Calc_Data(DataRegister, DataCRC);
-                    InputBuffer[Index] = DataRegister;
+                    if (Index < InputBufferSize) {
+                        InputBuffer[Index] = DataRegister;
+                    }
                     Index++;
                 } else if (Index == DataLength) {
                     /* CRC1 */
@@ -651,17 +616,21 @@ static void MSTP_Receive_Frame_FSM(
                     /* STATE DATA CRC - no need for new state */
                     /* indicate the complete reception of a valid frame */
                     if (DataCRC == 0xF0B8) {
-                        if ((DestinationAddress == This_Station) ||
+ 						if (Receive_State == MSTP_RECEIVE_STATE_DATA) {
-                            (DestinationAddress == MSTP_BROADCAST_ADDRESS)) {
                             /* ForUs */
-                            /* indicate that a frame with no data
-                               has been received */
                             MSTP_Flag.ReceivedValidFrame = true;
+                        } else {
+                            /* NotForUs */
+                            MSTP_Flag.ReceivedValidFrameNotForUs = true;
                         }
+
                     } else {
                         MSTP_Flag.ReceivedInvalidFrame = true;
                     }
                     Receive_State = MSTP_RECEIVE_STATE_IDLE;
+                } else {
+                    MSTP_Flag.ReceivedInvalidFrame = true;
+                    Receive_State = MSTP_RECEIVE_STATE_IDLE;
                 }
             }
             break;
@@ -722,6 +691,8 @@ static bool MSTP_Master_Node_FSM(
     bool matched = false;
     /* transition immediately to the next state */
     bool transition_now = false;
+    /* packet from the PDU Queue */
+    struct mstp_pdu_packet *pkt;
 
     /* some calculations that several states need */
     next_poll_station = (Poll_Station + 1) % (Nmax_master + 1);
@@ -752,6 +723,8 @@ static bool MSTP_Master_Node_FSM(
                    some bytes and had a timeout for some reason */
                 MSTP_Flag.ReceivedValidFrame = false;
                 MSTP_Flag.ReceivedInvalidFrame = false;
+                MSTP_Flag.ReceivedValidFrameNotForUs = false;
+                Master_State = MSTP_MASTER_STATE_NO_TOKEN;
                 transition_now = true;
             } else if (MSTP_Flag.ReceivedInvalidFrame == true) {
                 /* ReceivedInvalidFrame */
@@ -810,26 +783,27 @@ static bool MSTP_Master_Node_FSM(
             /* proprietary frames. */
         case MSTP_MASTER_STATE_USE_TOKEN:
             /* Note: We could wait for up to Tusage_delay */
-            if (!MSTP_Flag.TransmitPacketPending) {
+            if (Ringbuf_Empty(&PDU_Queue)) {
                 /* NothingToSend */
                 FrameCount = Nmax_info_frames;
                 Master_State = MSTP_MASTER_STATE_DONE_WITH_TOKEN;
                 transition_now = true;
             } else {
                 uint8_t frame_type;
-                if (MSTP_Flag.TransmitPacketDER) {
+                pkt = (struct mstp_pdu_packet *)Ringbuf_Pop_Front(
+                    &PDU_Queue);
+                if (pkt->data_expecting_reply) {
                     frame_type = FRAME_TYPE_BACNET_DATA_EXPECTING_REPLY;
                 } else {
                     frame_type = FRAME_TYPE_BACNET_DATA_NOT_EXPECTING_REPLY;
                 }
-                MSTP_Send_Frame(frame_type, TransmitPacketDest, This_Station,
+                MSTP_Send_Frame(frame_type, pkt->destination_mac, This_Station,
-                    (uint8_t *) & TransmitPacket[0], TransmitPacketLen);
+                    (uint8_t *) & pkt->buffer[0], pkt->length);
-                MSTP_Flag.TransmitPacketPending = false;
                 FrameCount++;
                 switch (frame_type) {
                     case FRAME_TYPE_BACNET_DATA_EXPECTING_REPLY:
                         /* SendAndWait */
-                        if (TransmitPacketDest == MSTP_BROADCAST_ADDRESS)
+                        if (pkt->destination_mac == MSTP_BROADCAST_ADDRESS)
                             Master_State = MSTP_MASTER_STATE_DONE_WITH_TOKEN;
                         else
                             Master_State = MSTP_MASTER_STATE_WAIT_FOR_REPLY;
@@ -1140,13 +1114,16 @@ static bool MSTP_Master_Node_FSM(
             /* a proprietary frame that expects a reply is received. */
         case MSTP_MASTER_STATE_ANSWER_DATA_REQUEST:
             /* Note: we could wait for up to Treply_delay */
-            if (MSTP_Flag.TransmitPacketPending) {
+            matched = false;
+            if (!Ringbuf_Empty(&PDU_Queue)) {
+                pkt = (struct mstp_pdu_packet *)Ringbuf_Get_Front(
+                    &PDU_Queue);
                 matched =
                     dlmstp_compare_data_expecting_reply(&InputBuffer[0],
-                    DataLength, SourceAddress, &TransmitPacket[0],
+                    DataLength, SourceAddress, &pkt->buffer[0],
-                    TransmitPacketLen, TransmitPacketDest);
+                    pkt->length, pkt->destination_mac);
             }
-            if (MSTP_Flag.TransmitPacketPending && matched) {
+            if (matched) {
                 /* Reply */
                 /* If a reply is available from the higher layers  */
                 /* within Treply_delay after the reception of the  */
@@ -1155,14 +1132,15 @@ static bool MSTP_Master_Node_FSM(
                 /* then call MSTP_Send_Frame to transmit the reply frame  */
                 /* and enter the IDLE state to wait for the next frame. */
                 uint8_t frame_type;
-                if (MSTP_Flag.TransmitPacketDER) {
+                pkt = (struct mstp_pdu_packet *)Ringbuf_Pop_Front(
+                    &PDU_Queue);
+                if (pkt->data_expecting_reply) {
                     frame_type = FRAME_TYPE_BACNET_DATA_EXPECTING_REPLY;
                 } else {
                     frame_type = FRAME_TYPE_BACNET_DATA_NOT_EXPECTING_REPLY;
                 }
-                MSTP_Send_Frame(frame_type, TransmitPacketDest, This_Station,
+                MSTP_Send_Frame(frame_type, pkt->destination_mac, This_Station,
-                    (uint8_t *) & TransmitPacket[0], TransmitPacketLen);
+                    (uint8_t *) & pkt->buffer[0], pkt->length);
-                MSTP_Flag.TransmitPacketPending = false;
                 Master_State = MSTP_MASTER_STATE_IDLE;
             } else {
                 /* DeferredReply */
@@ -1197,14 +1175,18 @@ int dlmstp_send_pdu(
     unsigned pdu_len)
 {       /* number of bytes of data */
     int bytes_sent = 0;
+    struct mstp_pdu_packet *pkt;
+    uint16_t i = 0;
 
-    if (MSTP_Flag.TransmitPacketPending == false) {
+    pkt = (struct mstp_pdu_packet *)Ringbuf_Alloc(&PDU_Queue);
-        MSTP_Flag.TransmitPacketDER = npdu_data->data_expecting_reply;
+    if (pkt) {
-        TransmitPacket = pdu;
+        pkt->data_expecting_reply = npdu_data->data_expecting_reply;
-        TransmitPacketLen = pdu_len;
+        for (i = 0; i < pdu_len; i++) {
+            pkt->buffer[i] = pdu[i];
+        }
+        pkt->length = pdu_len;
+        pkt->destination_mac = dest->mac[0];
         bytes_sent = pdu_len;
-        TransmitPacketDest = dest->mac[0];
-        MSTP_Flag.TransmitPacketPending = true;
     }
 
     return bytes_sent;
@@ -1226,6 +1208,7 @@ uint16_t dlmstp_receive(
     }
     /* only do receive state machine while we don't have a frame */
     if ((MSTP_Flag.ReceivedValidFrame == false) &&
+        (MSTP_Flag.ReceivedValidFrameNotForUs == false) &&
         (MSTP_Flag.ReceivedInvalidFrame == false)) {
         MSTP_Receive_Frame_FSM();
     }
@@ -1259,7 +1242,7 @@ void dlmstp_set_mac_address(
            mac_address,
            EEPROM_MSTP_MAC_ADDR); */
         if (mac_address > Nmax_master)
-            dlmstp_set_max_master(mac_address);
+            dlmstp_set_max_master(127);
     }
 
     return;
@@ -1281,7 +1264,11 @@ uint8_t dlmstp_mac_address(
 void dlmstp_set_max_info_frames(
     uint8_t max_info_frames)
 {
-    /* not writable - fixed at 1 */
+    if (max_info_frames >= 1) {
+        Nmax_info_frames = max_info_frames;
+    }
+
+    return;
 }
 
 uint8_t dlmstp_max_info_frames(