Thread: Understanding the sprintf function

I want to transmit a variable over UART and also LCD, the UART is a generated function with argument of uint8_t, the data i need to transmit is both signed and unsigned and it is 16 bit. How do i transmit the signed value if the argument is unsigned value?

Code:

void USARTWrite(uint8_t txData)
{
}

My array is of size of 100 of bit16. To transmit the data i have used the sprintf function and i have made mistake in that as well. I have written something like this

Code:

void Send(int16_t a_data_s16)
{
    int16_t l_buffer_a[10];
    uint8_t l_index_u8=0;
    sprintf(l_buffer_a,"%d",a_data_s16);
    while(l_buffer_a[l_index_u8] != 0)
    {
       USARTWrite((uint8_t)l_buffer_a[l_index_u8]);
       l_index_u8++;
    }
}

I realized that int sprintf(char *str, const char *string,...);
, so i made a mistake of making it as int16_t. I have completely messed up all the code. What is the best approach now. Please help.

I have multiple doubts, hopefully i can get clarified here

Code:

int16 datatotransmit[100];

int main()
{
  while (index <= 90)   /*transmitting 90 elements of datatotransmit array */
  {
     send(datatotransmit[index]);
     index++;
  }
}

void send(int16 data)
{
char buffer[10]; 
sprintf(buffer,"%d",data);
while(buffer[index] != 0)
 {
    UartSend((uint8)buffer[index]);
     index++;
 }

}

/*UartSend is the function generated by the library which accepts uint8*/
UartSend(uint8 data)
{
   /*Function to send data over UART*/
}

datatotransmit is an array filled by other function, let us say it has filled with the below values

Code:

datatotransmit[0] = 123;
datatotransmit[1] = 512;
datatotransmit[2] = -400;
datatotransmit[3] = -512;

Q1. Is the send function correct?
Q2. For example if the datatotransmit[0] = 123;
then input to UartSend will be
Ascii value of '1', '2', '3' is it correct? and for negative values it will be for example -512
Ascii value of '-', '5','1','2' ? created by Send() function.

Please help.

Yes I receive data, I had problems receiving for higher values, then I figured one mistake of argument, I defined as uint instead of the signed. I am having difficulty in transmitting new line hence inserted comma between numbers.
The other thing I want to try is to do integer multiplication and insert a dot at a fixed place. For example if it is 412, I want to display 4.12V. I am trying on Uart and LCD as well. May be I will attempt and show the code.