Help, error with types on constants and var's

[koli]

Hi,
even they are declared as same type (char) I get the next error when I try to compile source:
a value of type 'const void' can't be assigned to an entity type 'unsigned char'
I'm using codevision AVR

The example of code is:

char PosSend(char ServoID, char SpeedLevel, char Position)
{
char Current;
SendOperCommand((SpeedLevel<<5)|ServoID, Position);
GetByte(TIME_OUT1);
Current = GetByte(TIME_OUT1); // LINE WHERE I GOT THE ERROR
return Current;
}

This code is an example of robobuilder-creator-users-manual.pdf page 63

[i-Bot]

The function prototype for GetByte in the example appears to have a void return:
void GetByte(char timeout); // Receive 1 Byte from serial port
I guess this should be a char returned to match your serial routines.

[koli]

thanks!!!

Please did you may, to put on the code of the function GetByte and that of the SendByte??

not find in any site,
GetByte receibe 1 byte from serial port
SendByte send 1 byte to serial port

Thank you very much in advance.

[l3v3rz]

I think you need these two routines .... (from Comm.c)

Note - the timeout seems to fixed at RX_T_OUT. Also needs the Timer Int running to update gMSec.

Code: Select all


#define RX_T_OUT       20  // from Comm.h

//------------------------------------------------------------------------------
// void SendByte(BYTE)
//------------------------------------------------------------------------------
void sciTx0Data(BYTE td)
{
   while(!(UCSR0A&(1<<UDRE)));    
   UDR0=td;
}


//------------------------------------------------------------------------------
// BYTE ReadByte()
//------------------------------------------------------------------------------
BYTE sciRx0Ready()
{
   WORD   startT;
   startT = gMSEC;
   while(!(UCSR0A&(1<<RXC)) ){    
        if(gMSEC<startT>RX_T_OUT) break;
        }
      else if((gMSEC-startT)>RX_T_OUT) break;
   }
   return UDR0;
}


[koli]

These routines give me many mistakes

//------------------------------------------------------------------------------
// void SendByte(BYTE)
//------------------------------------------------------------------------------
void sciTx0Data(BYTE td) // ERROR:DECLARATION SYNTAX ERROR
{
while(!(UCSR0A&(1<<UDRE)));
UDR0=td; //ERROR: a value of type(*)()' can't be assigned to an entity of type unsigned 'sfrb'

}

void sciTx1Data(BYTE td)// ERROR:DECLARATION SYNTAX ERROR
{
while(!(UCSR1A&(1<<UDRE)));
UDR1=td; //ERROR: a value of type(*)()' can't be assigned to an entity of type unsigned 'unsigned char'

}

Not as solving them

Thank you

[l3v3rz]

assuming you're using gcc avr or windows equivalent then make sure you have Macro.h or at least include the following

Code: Select all

#define   BYTE   unsigned char
#define   WORD   unsigned int
#define   UDRE   5
#define   RXC      7

#define DATA_REGISTER_EMPTY   (1<<UDRE)
#define RX_COMPLETE         (1<<RXC)

The receive function requires the timer interrupt to enable timeouts, or you could remove that code

[koli]

Thank you, Macro.h was not using.

I am begginer, and do not know like well this works.