union/struct problem

[mike holeton]

I am trying to use a struct pointer and it gives me the error below (MsgPtr->Res = 0; // Is Not a Member. Anyone have a solution?

union J1939_MESSAGE_UNION {
struct {
int8 PDUFormat_Top : 3; // This needs pre and post processing.
int8 DataPage : 1;
int8 Res : 1;
int8 Priority : 3;
char PDUFormat; // CA should use only PDUFormat.
char PDUSpecific;
char SourceAddress;
int8 DataLength : 4;
int8 RTR : 4; // RTR bit, value always 0x00
char Data[J1939_DATA_LENGTH];
};
char Array[J1939_MSG_LENGTH + J1939_DATA_LENGTH];
};

#define GroupExtension PDUSpecific
#define DestinationAddress PDUSpecific
typedef union J1939_MESSAGE_UNION J1939_MESSAGE;


union J1939_FLAGS_UNION {
struct {
int8 CannotClaimAddress : 1;
int8 WaitingForAddressClaimContention : 1;
int8 GettingCommandedAddress : 1;
int8 GotFirstDataPacket : 1;
int8 ReceivedMessagesDropped : 1;
};
char FlagVal;
};

typedef union J1939_FLAGS_UNION J1939_FLAG;


void SendOneMessage( J1939_MESSAGE *MsgPtr ) {
char Loop;
char *RegPtr;
char Temp;

// Set up the final pieces of the message and make sure DataLength isn't
// out of spec.
MsgPtr->Res = 0; // ERROR, THE COMPILER SAYS THIS IS NOT A MEMBER HELP!
MsgPtr->RTR = 0;
if (MsgPtr->DataLength > 8)
MsgPtr->DataLength = 8;

// Put PDUFormat into the structure to match the J1939-CAN format. This
// involves splitting the original value in PDUFormat into two pieces,
// leaving some holes for the TXBnSIDL register, and setting the EXIDE bit.
MsgPtr->PDUFormat_Top = MsgPtr->PDUFormat >> 5; // Put the top three bits into SID5-3
Temp = MsgPtr->PDUFormat & 0x03; // Save the bottom two bits.
MsgPtr->PDUFormat = (MsgPtr->PDUFormat & 0x1C) << 3; // Move up bits 4-2 into SID2-0.
MsgPtr->PDUFormat |= Temp | 0x08; // Put back EID17-16, set EXIDE.

// Wait until the requested buffer can be used to transmit. We shouldn't
// need a time-out here unless something else in the design isn't working
// (or we have to send a LOT of network management messages).
while (MAPPED_CONbits.MAPPED_TXREQ);

// Load the message buffer. Load the first 5 bytes of the message,
// then load whatever part of the data is necessary.
RegPtr = &MAPPED_SIDH;
for (Loop=0; Loop<J1939_MSG_LENGTH+MsgPtr->DataLength; Loop++, RegPtr++)
*RegPtr = MsgPtr->Array[Loop];

// Now tell the module to send the message.
MAPPED_CONbits.MAPPED_TXREQ = 1;
}

[PCM programmer]

I think you need to add the items shown in bold below.

[mike holeton]

Thank You, I'll give it a try.