pic rs232 interface with labview

[MoReese]

I'm a bit confused

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@neomus wrote:

Dear Coq

Yes the PIC is sending 10 bit ADC resolution by two bytes. I am getting the values and it displays properly on the LV as you will see from the previously attached VI. Now my problem is writing to serial port. I want to write 8 bit variable data to serial port. PIC will read this value and do the variable task.

Please advise me.

Reggards

Ananth 

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I'm a bit confused from your postings.  Are you having trouble sending data to the PIC or sending data from the PIC.  You seem to contradict yourself, in that you state the 10 bit ADC value is received by LV but you can't send data to the PIC from LV.  But you also state that your LEDs are working after receiving data from LV (Or are you referring to the LED on yoru fp?).  Please explain clearly what the issue is and what you are trying to accomplish so we aren't running around in circles.

[neomus]

i have problem with sending data from LV to PIC. Sending data from PIC to Labview is OK (ADC value). One LED is connected at PortA.3 of PIC. when i send "a" the LED should be ON and when i send "b" the LED should be OFF. My PIC is not receiving anything from LV. Source code in MIKROC is below. I have tested this code with C# and it is working.

Please advise me

// LCD module connections
sbit LCD_RS at RB4_bit;
sbit LCD_EN at RB5_bit;
sbit LCD_D4 at RB0_bit;
sbit LCD_D5 at RB1_bit;
sbit LCD_D6 at RB2_bit;
sbit LCD_D7 at RB3_bit;
sbit LCD_RS_Direction at TRISB4_bit;
sbit LCD_EN_Direction at TRISB5_bit;
sbit LCD_D4_Direction at TRISB0_bit;
sbit LCD_D5_Direction at TRISB1_bit;
sbit LCD_D6_Direction at TRISB2_bit;
sbit LCD_D7_Direction at TRISB3_bit;
// End LCD module connections

 # include "built_in.h"

unsigned char uart_rd;
unsigned char ch;                    //
unsigned int adc_rd;                 // Declare variables
unsigned int tmp1;
unsigned int tmp2;
char *text;                          //
long tlong;                          //

void main() {

INTCON.F7 = 0;   //Global interrupt Disabled
 INTCON2.F7 = 1;  //portB Pullup resistor disabled
RCSTA.F7 = 1;       // USART Enabled

 CMCON = 0x07;      //Comparator OFF
  ADCON0.F0 = 1;     //ADC Module Enabled
  ADCON0.F5 = 0, ADCON0.F4 = 0, ADCON0.F3 = 1, ADCON0.F2 = 0;  //ADC(2) Enabled
  
 ADCON1 = 0x0C;     //Analog channel A0,A1,A2 Read as analog input
 TRISA =0x07;
PORTA.F3 =0;
Lcd_Init();
Lcd_Cmd(_LCD_CLEAR);               // Clear display
  Lcd_Cmd(_LCD_CURSOR_OFF);          // Cursor off
  Lcd_Out(1,6,"LABVIEW");
  delay_ms(1000);
  Lcd_Cmd(_LCD_CLEAR);

UART1_Init(9600);
delay_ms(100);
while(1) {

if (UART1_Data_Ready()) {
 uart_rd = UART1_Read();

 if (uart_rd == 'a') {
    Lcd_Out(1,6,"ON ");                 // Write text in first row
  PORTA.F3 =1;



 }
  if (uart_rd == 'b') {
    Lcd_Out(1,6,"OFF");                 // Write text in first row
  PORTA.F3 =0;
 


 }

}
         adc_rd = ADC_Read(2);        // A/D conversion. Pin RA2 is an input.
         
        tlong = (long)adc_rd * 5000; // Convert the result in millivolts
        tlong = tlong / 1024;        // 0..1023 -> 0-5000mV
        ch = tlong / 1000;           // Extract volts (thousands of millivolts)
                                     // from result
        Lcd_Chr(2,9,48+ch);          // Write result in ASCII format
        Lcd_Chr_CP('.');
        ch = (tlong / 1000) % 10;     // Extract thousands of millivolts
        Lcd_Chr_CP(48+ch);
        ch = (tlong / 100) % 10;     // Extract hundreds of millivolts
        Lcd_Chr_CP(48+ch);           // Write result in ASCII format
        ch = (tlong / 10) % 10;      // Extract tens of millivolts
        Lcd_Chr_CP(48+ch);           // Write result in ASCII format
        ch = tlong % 10;             // Extract digits for millivolts
        Lcd_Chr_CP(48+ch);           // Write result in ASCII format
        Lcd_Chr_CP('V');
        Delay_ms(1);
        
          tmp1 = Lo(adc_rd);
          tmp2 = Hi(adc_rd);
          if (UART1_Tx_Idle() == 1) {
           Lcd_Out(1,1,"byt1");
          UART1_Write(tmp1);
          }
          delay_ms(10);
          if (UART1_Tx_Idle() == 1) {
          Lcd_Out(1,1,"byt2");
          UART1_Write(tmp2);
          }
          delay_ms(100);
}
}

Regards

Ananth

[neomus]

Hi

Please find the simple read & write VI. I am getting the ADC value from PIC and it displays on LV. If i want to write any value from LV to port i use the boolean in the VI and control the LED connected to PIC. the problem is if i write any value to the port the PIC is not receiving it. Please advise me where i am making mistake.

Regards

Ananth

[MoReese]

Have you tried using HyperTerminal to send the data?  Try it.  If it still doesn't work, the problem is not with LV, but with your programming or hardware setup.  Have you scoped the signal to the PIC?  I don't see any reason why LV should not be sending out data.

[neomus]

Yes i have tried with hyper terminal. When i send the variable data through hyper terminal PIC is receiving the value and doing the task. did you check the last VI i have posted. Is the code okay?. Also i have added a delay in the write and still having the problem. please check the attached VI with delay.

Regards

Ananth 

[MoReese]

Could it be you lack a control character such as CRLF (0x0D0A) to terminate your string?  I don't know anything about your PIC, but it's worth a mention.  I assume you scoped the signal with LV also?  What did you receive?

[ifriad]

Hi neomus 

I am trying to do something similar I am only interested in reading values from the pic microcontroller could you please send me your vi saved as labview 8.5 as my labview version is 8.5.

This will be very generous of your.

Cheers Ihab

[crossrulz]

The problem with trying to talk with a microcontroller is that whoever programs the microcontroller will likely dictate the message protocol.  You should have a nice long discussion with whoever wrote the code for your pic.  But in general, the Simple Serial Read Write example is a decent starting point.

[balzzzNI]

hello 

          greetings by balzzz 

   I need a help from you. i am having a particular data in my PIC 16F877A micro controller could you guide me in such a way that i could able to monitor the data in labVIEW 

my mail ID is : balakumar.p11@gmail.com

contact me @ 9809425083

[deceased]

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@balzzzNI wrote:

hello 

          greetings by balzzz 

   I need a help from you. i am having a particular data in my PIC 16F877A micro controller could you guide me in such a way that i could able to monitor the data in labVIEW 

my mail ID is : balakumar.p11@gmail.com

@contact me @ 9809425083

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Do you have the microcontroller code? Can you edit it? If so, you have the best chance. You will need to configure the UART and make some comms protocol for receiving commands and returning data.

You will then need some kind of line driver/level shifter for the UART comms. A max233 ciruit is easy and is sufficient for standard serial.

How easy this all is depends on your level of expertise. Just thank your lucky stars that most micros have UARTs now, coding them yourself in ASM is not so much fun.

A trick I quite often like to do is to tie one of the unused serial lines to the microcontroller reset line, so I can remotely trigger a reset by toggling a line in LabVIEW.