Interfacing UART with tms320C6745
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This document discusses interfacing a UART (Universal Asynchronous Receiver/Transmitter) with a TMS320C6745 digital signal processor (DSP). It provides an introduction to RS-232 standards and UARTs. It describes using a level converter like a MAX232 to convert voltage levels between TTL and RS-232. It shows a schematic for interfacing with a UART and describes UART registers. It provides examples of C code for transmitting and receiving data with a UART on a TMS320C6745 DSP.
![Technology beyond the Dreams™ Copyright © 2014 Pantech Prolabs India Pvt Ltd.
UART Transmit Program
#include "stdio.h"
#include "c6745.h"
#include "c6745_uart.h"
void main()
{
Int16 i;
Uint8 j=64;
UART_Handle uart0;
char message[]={"The C6745-UART is fine !nr"};
/* Initialize BSL */
C6745_init( );
/* Open Uart Handle */
uart0 = C6745_UART_open( 1, 9600 );
while(1)
{
for(i=0;i<27;i++)
{
while( C6745_UART_xmtReady( uart0 ) ); // Wait for uart_tx ready
C6745_UART_putChar( uart0, message[i] ); // Write 1 byte
}
}
}](https://image.slidesharecdn.com/interfacinguartwithtms320c6745-150501011934-conversion-gate01/85/Interfacing-UART-with-tms320C6745-7-320.jpg)
Interfacing UART with tms320C6745
- 2. Technology beyond the Dreams™ Copyright © 2014 Pantech Prolabs India Pvt Ltd. 1) Introduction: Serial interface (universal asynchronous receiver transmitter : UART) • RS232 standard and application, e.g. 2 2 RS232 port (UART) RS232 port (UART) RS232 standard 3 wires +10 V=‘0’=SPACE -10V=‘1’=MARK Pin2 Pin3 pin5 Pin3 Pin2 pin5 UART
- 3. Technology beyond the Dreams™ Copyright © 2014 Pantech Prolabs India Pvt Ltd. Universal asynchronous receiver transmitter : UART • RS232 is a serial communication standard • Since it is asynchronous, no external clock is needed, only 3 wires are required for the simplest RS232 connection {GND, tx(transmit), rx(receive)} 3 3 +10V=Logic 0=space -10V= Logic 1=markExercise: Sketch Bit Patterns for character A and B Start 0 1 2 3 4 5 6 7 stop Bit 0 to 7 (least sig. bit first ) time
- 4. Technology beyond the Dreams™ Copyright © 2014 Pantech Prolabs India Pvt Ltd. RS-232 Level Converter • Convert TTL to RS232 and RS232 to TTL voltage levels. The most commonly used RS-232 level converter is MAX232 and MAX3232. • This IC includes charge pump which can generate RS232 voltage levels (-10V and +10V) from 3.3V power supply. It also includes two receiver and two transmitters and is capable of full-duplex UART/USART communication. • RS-232 communication enables point-to-point data transfer
- 5. Technology beyond the Dreams™ Copyright © 2014 Pantech Prolabs India Pvt Ltd. Schematic Diagram to Interface With UART
- 6. Technology beyond the Dreams™ Copyright © 2014 Pantech Prolabs India Pvt Ltd. UART Registers
- 7. Technology beyond the Dreams™ Copyright © 2014 Pantech Prolabs India Pvt Ltd. UART Transmit Program #include "stdio.h" #include "c6745.h" #include "c6745_uart.h" void main() { Int16 i; Uint8 j=64; UART_Handle uart0; char message[]={"The C6745-UART is fine !nr"}; /* Initialize BSL */ C6745_init( ); /* Open Uart Handle */ uart0 = C6745_UART_open( 1, 9600 ); while(1) { for(i=0;i<27;i++) { while( C6745_UART_xmtReady( uart0 ) ); // Wait for uart_tx ready C6745_UART_putChar( uart0, message[i] ); // Write 1 byte } } }
- 8. Technology beyond the Dreams™ Copyright © 2014 Pantech Prolabs India Pvt Ltd. UART Receive &Transmit Program #include "stdio.h" #include "c6745.h" #include "c6745_uart.h“ void main() { UART_Handle uart0; char receive; /* Initialize BSL */ C6745_init( ); /* Open Uart Handle */ uart0 = C6745_UART_open( 1, 9600 ); while(1) { while(((uart0->regs->LSR) & 0x1)==0); receive = uart0->regs->THR; while( C6745_UART_xmtReady( uart0 ) ); // Wait for uart_tx ready C6745_UART_putChar( uart0, receive ); // Write 1 byte } }