arm + serial + uart + monitor in visual c# -

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solved: enabled property dtr of serial port component of visual studio. working fine. thank all.

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i need help.

i wrote program in arm processor sends character 'a' through uart (usb). frequency 1 character/second. so, wrote program in visual c# receive character , show in text box. simple program.

the configurations of serial communications ok (baud_rate, stopbit, parity, data_bits)

the problem: cannot read character sent arm processor.

the facts:

1 - arm program working correctly in putty.

2 - visual c# program working correctly arduino board has same code arm has.

please guys, codes , if can, me.

this code of arm:

#include "inc/hw_ints.h" #include "inc/hw_memmap.h" #include "inc/hw_types.h" #include "driverlib/debug.h" #include "driverlib/gpio.h" #include "driverlib/interrupt.h" #include "driverlib/sysctl.h" #include "driverlib/uart.h" #include "drivers/rit128x96x4.h"  //***************************************************************************** // //! \addtogroup example_list //! <h1>uart echo (uart_echo)</h1> //! //! example application utilizes uart echo text.  first uart //! (connected ftdi virtual serial port on evaluation board) //! configured in 115,200 baud, 8-n-1 mode.  characters received on //! uart transmitted uart. // //*****************************************************************************  //***************************************************************************** // // error routine called if driver library encounters error. // //***************************************************************************** #ifdef debug void __error__(char *pcfilename, unsigned long ulline) { } #endif  //***************************************************************************** // // uart interrupt handler. // //***************************************************************************** void uartinthandler(void) {     unsigned long ulstatus;      //     // interrrupt status.     //     ulstatus = uartintstatus(uart0_base, true);      //     // clear asserted interrupts.     //     uartintclear(uart0_base, ulstatus);      //     // loop while there characters in receive fifo.     //     while(uartcharsavail(uart0_base))     {         //         // read next character uart , write uart.         //         //uartcharputnonblocking(uart0_base, uartchargetnonblocking(uart0_base));         uartcharputnonblocking(uart0_base,'a');          sysctldelay(16666666); //1.2 ms       } }  //***************************************************************************** // // send string uart. // //***************************************************************************** void uartsend(const unsigned char *pucbuffer, unsigned long ulcount) {     //     // loop while there more characters send.     //     while(ulcount--)     {         //         // write next character uart.         //         uartcharputnonblocking(uart0_base, *pucbuffer++);     } }  //***************************************************************************** // // example demonstrates how send string of data uart. // //***************************************************************************** int main(void) {     //     // set clocking run directly crystal.     //     //sysctlclockset(sysctl_sysdiv_1 | sysctl_use_osc | sysctl_osc_main | sysctl_xtal_8mhz);     sysctlclockset(sysctl_sysdiv_4 | sysctl_use_pll | sysctl_osc_main | sysctl_xtal_8mhz);      //     // initialize oled display , write status.     //     rit128x96x4init(1000000);     rit128x96x4stringdraw("uart echo",            36,  0, 15);     rit128x96x4stringdraw("port:   uart 0",       12, 16, 15);     rit128x96x4stringdraw("baud:   115,200 bps",  12, 24, 15);     rit128x96x4stringdraw("data:   8 bit",        12, 32, 15);     rit128x96x4stringdraw("parity: none",         12, 40, 15);     rit128x96x4stringdraw("stop:   1 bit",        12, 48, 15);      //     // enable peripherals used example.     //     sysctlperipheralenable(sysctl_periph_uart0);     sysctlperipheralenable(sysctl_periph_gpioa);      //     // enable processor interrupts.     //     intmasterenable();      //     // set gpio a0 , a1 uart pins.     //     gpiopintypeuart(gpio_porta_base, gpio_pin_0 | gpio_pin_1);      //     // configure uart 115,200, 8-n-1 operation.     //     uartconfigsetexpclk(uart0_base, sysctlclockget(), 9600,                         (uart_config_wlen_8 | uart_config_stop_one |                          uart_config_par_none));      //     // enable uart interrupt.     //     intenable(int_uart0);     uartintenable(uart0_base, uart_int_rx | uart_int_rt);      uartfifoenable(uart0_base);     uartenable(uart0_base);      //     // prompt text entered.     //     uartsend((unsigned char *)"enter text: ", 12);      //     // loop forever echoing data through uart.     //     while(1)     {      } } 

this visual c# code:

using system; using system.collections.generic; using system.componentmodel; using system.data; using system.drawing; using system.linq; using system.text; using system.threading.tasks; using system.windows.forms; using system.io.ports;    namespace interfacearduinovs2013 {     public partial class form1 : form     {          string rxstring;          public form1()         {             initializecomponent();             timercom.enabled = true;         }          private void atualizalistacoms()         {             int i;             bool quantdiferente;    //flag para sinalizar que quantidade de portas mudou              = 0;             quantdiferente = false;              //se quantidade de portas mudou             if (combobox1.items.count == serialport.getportnames().length)             {                 foreach (string s in serialport.getportnames())                 {                     if (combobox1.items[i++].equals(s) == false)                     {                         quantdiferente = true;                     }                 }             }             else             {                 quantdiferente = true;             }              //se não foi detectado diferença             if (quantdiferente == false)             {                 return;                     //retorna             }              //limpa combobox             combobox1.items.clear();              //adiciona todas com diponíveis na lista             foreach (string s in serialport.getportnames())             {                 combobox1.items.add(s);             }             //seleciona primeira posição da lista             combobox1.selectedindex = 0;         }          private void timercom_tick(object sender, eventargs e)         {             atualizalistacoms();         }          private void btconectar_click(object sender, eventargs e)         {             if (serialport1.isopen == false)             {                 try                 {                     serialport1.portname = combobox1.items[combobox1.selectedindex].tostring();                     serialport1.open();                  }                 catch                 {                     return;                  }                 if (serialport1.isopen)                 {                     btconnect.text = "disconnect";                     combobox1.enabled = false;                  }             }             else             {                  try                 {                     serialport1.close();                     combobox1.enabled = true;                     btconnect.text = "connect";                 }                 catch                 {                     return;                 }              }         }          private void form1_formclosed(object sender, formclosedeventargs e)         {             if(serialport1.isopen == true)  // if port opened              serialport1.close();            //close port         }          private void btenviar_click(object sender, eventargs e)         {             if(serialport1.isopen == true)                      serialport1.write(textboxsend.text);  //send text in textbox             rxstring = serialport1.readexisting();             messagebox.show(rxstring);         }          private void serialport1_datareceived(object sender, serialdatareceivedeventargs e)         {             rxstring = serialport1.readexisting(); //read data serial port             messagebox.show(rxstring);             this.invoke(new eventhandler(tratadadorecebido));   //call thread write data on textbox          }          private void tratadadorecebido(object sender, eventargs e)         {              textboxreceive.appendtext(rxstring);         }     } } 

most have problem of baud rate. in c# code not see anywhere setting baud rate of com port. if 115200 print on arm board problem in arm board itself. printing 115,200 baud rate initializing arm board @ 9600 8n1

// // configure uart 115,200, 8-n-1 operation. // uartconfigsetexpclk(uart0_base, sysctlclockget(), 9600,                     (uart_config_wlen_8 | uart_config_stop_one |                      uart_config_par_none)); 

initialize corectly both ends of communication line before opening ports , try again. smaller baud rate on transmitter result in no characters printed on high speed configured receiver. on other hand, slow configured receiver(9600) capture garbage high speed transmitter.