UART
Revision as of 17:17, 28 December 2014 by Explorer (Talk | contribs)

UART

UART_Init

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Defination void UART_Init(uint32_t v_baudRate_u32)
Input Arguments *uint32_t : Baudrate to be configured.
Return Value none
Description This function is used to initialize the UART at specified baud rate.
If the requested baud rate is not within the supported range then the default baud rate of 9600 is set.
Usage UART_Init(9600); //Initialize the uart module for 9600 baud rate;



UART_SetBaudRate

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Defination void UART_SetBaudRate(uint32_t v_baudRate_u32)
Input Arguments *uint32_t : Baudrate to be configured.
Return Value none
Description This function is used to Set/Change the baudrate on the fly.
If the requested baud rate is not within the supported range then the default baud rate of 9600 is set.
Usage UART_SetBaudRate(9600); //Configures the uart module for 9600 baud rate;



UART_TxChar

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Defination void UART_TxChar(char v_uartData_u8)
Input Arguments char:Ascii value of the character to be transmitted.
Return Value none
Description This function is used to transmit a char through UART module.
Usage

char ch='A';
UART_TxChar(ch); //Transmits the Char stored in ch
UART_TxChar('A'); //Transmits the Char 'A'
UART_TxChar(65); //Transmits the Char 'A'
UART_TxChar(0x41); //Transmits the Char 'A'

UART_RxChar

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Defination char UART_RxChar()
Input Arguments none.
Return Value char: Ascii value of the character received
Description This function is used to receive a char from UART module. It waits till a char is received and returns its acsii value after reception.
Usage

char ch;
ch = UART_RxChar(); //Receives a Ascii char and copies into ch

UART_TxString

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Defination void UART_TxString(char *p_stringPointer_u8)
Input Arguments char *:String(Address of the string) to be transmitted.
Return Value none
Description This function is used to transmit a NULL terminated string through UART.
Usage

char myString[]={"hello, world"};
UART_RxString(myString);
UART_RxString("\n\rgood morning");

UART_RxString

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Defination void UART_RxString(char *p_stringPointer_u8)
Input Arguments char *: Address of the string/Buffer where the received data needs to be stored
Return Value none
Description This function is used to receive a ASCII string through UART till the carriage_return/New_line.

The stream of data is copied to the buffer till carriage_return/New_line is encountered.
Once the Carriage_return/New_Line is received the string will be null terminated.

Usage

char buffer[50];
UART_RxString(buffer); //Receives a string from UART and copies into buffer

UART_TxDecimalNumber

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Defination void UART_TxDecimalNumber(uint32_t v_decNumber_u32, uint8_t v_numOfDigitsToTransmit_u8)
Input Arguments
  • uint32_t: Number to be transmitted on UART.
  • uint8_t : Number of digits to be transmitted
Return Value none
Description This function is used to transmit a max of 10digit decimal number.2nd parameter specifies the number of digits from the right side to be transmitted .

The output for the input combinations is as below.

  • (12345,4) then 4-digits ie. 2345 will be transmitted
  • (12345,6) then 6-digits ie. 012345 will be transmitted
  • (12345,C_DefaultDigitsToTransmit) then 12345 will be transmitted.
Usage

uint32_t decNumber = 123456;
UART_TxDecimalNumber(decNumber,5); //Transmit last 5-digits of Number
UART_TxDecimalNumber(12345,4); //Transmit last 4-digits of number

UART_TxHexNumber

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Defination void UART_TxHexNumber(uint32_t v_hexNumber_u32, uint8_t v_numOfDigitsToTransmit_u8)
Input Arguments uint32_t: Hexadecimal Number to be transmitted on UART.

uint8_t : Number of digits to be transmitted

Return Value none
Description This function is used to transmit a max of 10digit hex number.

2nd parameter specifies the number of digits from the right side to be transmitted . The output for the input combinations is as below .

  • (0x12AB,3) then 3-digits ie. 2AB will be transmitted
  • (0x12AB,6) then 6-digits ie. 0012AB will be transmitted
  • (0x12AB,C_DefaultDigitsToTransmit) then 12AB will be transmitted.
Usage

uint32_t hexNumber = 0x123456;
UART_TxHexNumber(hexNumber,5); //Transmit last 5-digits of hexNumber
UART_TxHexNumber(0xABCDEF,4); //Transmit last 4-digits of number

UART_TxBinaryNumber

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Defination void UART_TxBinaryNumber(uint32_t v_binNumber_u32, uint8_t v_numOfBitsToTransmit_u8)
Input Arguments
  • uint32_t: Hexadecimal Number to be transmitted on UART.
  • uint8_t : Number of bits to be transmitted
Return Value none
Description This function is used to transmit the binary equivalent of the given number.

2nd parameter specifies the number of LSB to be transmitted . The output for the input combinations is as below .

  • (10,4) then 4-LSB will be transmitted ie. 1010
  • (10,8) then 8-LSB will be transmitted ie. 00001010
  • (10,2) then 2-LSB will be transmitted ie. 10
Usage

uint32_t Number = 0xABCD;
UART_TxDecimalNumber(Number,16); //Transmit last 16-bits of Number
UART_TxDecimalNumber(0x1234,8); //Transmit last 8-bits of number

UART_TxFloatNumber

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Defination void UART_TxFloatNumber(float v_floatNumber_f32)
Input Arguments float: float Number to be transmitted on UART.
Return Value none
Description This function is used to transmit a floating point number. It supports 6-digits of precision.
  • Note :Float will be disabled by default as it takes huge controller resources .It can be enabled by changing value of Enable_UART_TxFloatNumber to 1 in uart.h
Usage

float Number = 1234.5678;
UART_TxFloatNumber(Number);
UART_TxFloatNumber(3.33333);

UART_Printf

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Defination void UART_Printf(const char *argList, ...)
Input Arguments variable length arguments similar to printf
Return Value none
Description This function is similar to printf function in C. It takes the arguments with specified format and transmits accordingly .

The supported format specifiers are as below.

  • %c: character
  • %d: decimal 16-Bit number
  • %l: decimal 32-Bit number
  • %b: binary
  • %s: string
  • %f: float
  • %x: hexadecimal
Usage

void main() { uint16_t decNum=1234;//16-bit
uint32_t longDec=12345678;//32-bit
float floatNum=1234.5678;
uint16_t hexNum=0xABCD;
char myString[]={"hello, world};

UART_Printf("%d %l %f %x %b %s",decNum,longDec,floatNum,hexNum,hexNum,myString);
UART_Printf("D:%d,L:%l,F=%f,H:%x,Str:%s",1234,12345678,123.456,0xAB,"hello"); }

Usage guide

#include"uart.h"
int main()
{
  char a_TxMsg_u8[]={"Good Morning"};
  char v_uartData_u8='A';
  uint16_t v_num_u16= 1234u;
  char a_readString_u8[50];
  char ch;
 
 
  UART_Init(9600);
  UART_TxString("\n\rProgram to illustrate the UART library usage ");
 
  UART_TxString(a_TxMsg_u8);    /* Transmit the message stored in a string */
  UART_TxString("\n\rChar:");
  UART_TxChar('X');             /* Transmit the specified Ascii character */
  UART_TxChar(v_uartData_u8);    /* Transmit the char stored in a variable */
 
  UART_TxString("\n\rDec:");
  UART_TxDecimalNumber(1234,5);  /* Transmit the specified digits of a number */
  UART_TxString(" Hex:");
  UART_TxHexNumber(0xABCD,5);    /* Note here the number of digits to transmit=5 */
  UART_TxString(" Bin:");        /* The number Transmitted on UART will be as below*/
  UART_TxBinaryNumber(0xABCD,16);/* dec=01234, hex=0ABCD, bin=1010101111001101*/
 
 
  UART_Printf("\n\rDec=%d Hex=%x Bin:%b str=%s",v_num_u16,v_num_u16,v_num_u16,a_TxMsg_u8);
  UART_Printf("\n\rDec=%d Hex=%x Bin:%b str=%s",123u,0xABCDu,0x55u,"hello,world");
 
  UART_Printf("\n\rEnter a String: ");
  UART_RxString(a_readString_u8);
  UART_Printf("\n\rEntered string is: %s",a_readString_u8);
 
  do
  {
 	UART_Printf("\n\rEnter 'E' to exit: ");
 	ch = UART_RxChar();
 	UART_Printf("\n\rYou entered: %c",ch);
  }while((ch!='E') && (ch!='e'));
 
 
  UART_Printf("\n\rEnjoy Embedded Programming");
  while(1);
 
  return 0;
}
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