dsPIC30F2010 ADC Programming in MikroC

Introduction

An Analog to Digital Converter (ADC) translates continuous voltage signal into a digital data that a digital or computer system could understands. For short, in most of modern micro-controllers have at least one dedicated ADC module inside. It range from 8-bit, 10-bit, 12-bit or even 16-bit in a mixed signal processor such as the MSP430 micro-controller series.

 

An ADC is needed in an audio sampling system, analog temperature reading, strain gauge, etc. Using a micro-controller's build-in ADC module is very cost effective reducing of complexities in hardware wiring. 

 

10-BIT HIGH SPEED A/D FUNCTIONAL BLOCK DIAGRAM

 

The dsPIC30F2010 has six-channel 10-bit ADC module that able to convert any analog input channel up to 500KSPS. It has a programmable reference voltage pins - AVREF+ and AVREF-, and select able ADC supply voltage pins - AVDD and AVSS . 

In some compilers there is no ADC library. So the programmer need configures its registers before allowing the ADC module to operate.

The A/D module has six 16-bit registers:

• A/D Control Register1 (ADCON1)
• A/D Control Register2 (ADCON2)
• A/D Control Register3 (ADCON3)
• A/D Input Select Register (ADCHS)
• A/D Port Configuration Register (ADPCFG)
• A/D Input Scan Selection Register (ADCSSL) 

 

The programmer needs to configure its, clock source/frequency, result preparation, number of analog inputs, reference voltage pins, etc.

 

dsPIC30F2010 ADC Programming in MikroC

Using MikroC, reading any ADC inputs is very easy. Because it has a ready-to-use function library. 

Library Routines

• ADCx_Init
• ADCx_Init_Advanced
• ADCx_Get_Sample
• ADCx_Read
• ADC_Set_Active
• ADC1_ActivateCore

ADC AN4 and LED 

Here I make a simple ADC reading example from AN4 pin that connects to a POT (on-board). I use its 10-bit resolution that ranges from 0 to 1023. If the result is over 512 an LED connects to RD0 will turn on, otherwise it will turns off.

 

Schematic Diagram: 

 

Schematic Diagram

 

It's the same to my dsPIC30F2010 DIY Prototype Board.

 

MikroC Source Code:

 

1. 
   unsigned int temp_res;
2. 
   
3. void main() {
4. 
   
5. TRISB = 0xFFFF; // PORTB is input
6. TRISD = 0; // PORTD is output
7. TRISF = 0; // PORTF is output
8. ADC1_Init(); // Enable ADC module
9. 
   
10. do {
11. temp_res = ADC1_Read(4); // Get 10-bit results of AD conversion
12. if(temp_res>=512) LATD=0;
13. else LATD=1;
14. } while(1);
15. }

 

ADC AN4 and Character LCD

Following the Mikroelektronika Development Board example, I use a character LCD to read the analog input from AN4, showing its analog voltage result on a 16x4 character LCD. 

 

Schematic Diagram

 

Schematic Diagram

 

 The voltage value displaying is in floating point format.

 

MikroC Source Code:

 

1. // LCD module connections
2. sbit LCD_RS at LATE0_bit;
3. sbit LCD_EN at LATE1_bit;
4. sbit LCD_D4 at LATE2_bit;
5. sbit LCD_D5 at LATE3_bit;
6. sbit LCD_D6 at LATE4_bit;
7. sbit LCD_D7 at LATE5_bit;
8. 
   
9. sbit LCD_RS_Direction at TRISE0_bit;
10. sbit LCD_EN_Direction at TRISE1_bit;
11. sbit LCD_D4_Direction at TRISE2_bit;
12. sbit LCD_D5_Direction at TRISE3_bit;
13. sbit LCD_D6_Direction at TRISE4_bit;
14. sbit LCD_D7_Direction at TRISE5_bit;
15. // End LCD module connections
16. 
    
17. unsigned char ch;
18. unsigned int adc_rd;
19. char *text;
20. long tlong;
21. 
    
22. void main() {
23. ADPCFG = 0xFFFF; // Configure AN pins as digital
24. 
    
25. Lcd_Init();
26. LCD_Cmd(_LCD_CURSOR_OFF); // send command to LCD (cursor off)
27. LCD_Cmd(_LCD_CLEAR); // send command to LCD (clear LCD)
28. 
    
29. text = "mikroElektronika"; // assign text to string
30. LCD_Out(1,1,text); // print string a on LCD, 1st row, 1st column
31. text = "LCD example"; // assign text to string
32. LCD_Out(2,3,text); // print string a on LCD, 2nd row, 1st column
33. 
    
34. Delay_ms(7000);
35. text = "dsPIC30F2010 ADC";
36. LCD_Out(1,1,text);
37. text = "Voltage: "; // assign text to string
38. while (1) {
39. adc_rd = ADC1_read(4); // get ADC value from 2nd channel
40. LCD_Out(2,1,text); // print string a on LCD, 2nd row, 1st column
41. 
    
42. tlong = (long)adc_rd * 5000; // covert adc reading to milivolts
43. tlong = tlong / 1023; // 0..1023 -> 0-5000mV
44. 
    
45. ch = tlong / 1000; // extract volts digit
46. LCD_Chr(2,10,48+ch); // write ASCII digit at 2nd row, 9th column
47. LCD_Chr_CP('.');
48. 
    
49. ch = (tlong / 100) % 10; // extract 0.1 volts digit
50. LCD_Chr_CP(48+ch); // write ASCII digit at cursor point
51. 
    
52. ch = (tlong / 10) % 10; // extract 0.01 volts digit
53. LCD_Chr_CP(48+ch); // write ASCII digit at cursor point
54. 
    
55. LCD_Chr_CP('V');
56. 
    
57. Delay_ms(100);
58. }
59. }//~!

 

I tested this example on my DIY dsPIC30F2010 Prototype Board.

 

Reading +5.00V

  

Reading +2.53V

  

Reading 0.00V

Sending the ADC Data Over The Serial Port

We can send the ADC conversion data over the serial port using additional C sprintf and UART function.

 

MikroC Source Code:

1. 
   unsigned int adc_rd;
2. char *text;
3. float voltage;
4. 
   
5. void main() {
6. ADPCFG = 0xFFFF;
7. // Initialize UART module at 9600 bps
8. UART1_Init(9600);
9. Delay_ms(10);
10. text = "dsPIC30F2010 ADC UART Example\n\r";
11. UART1_Write_Text(text); // Write message on UART
12. 
    
13. while(1){
14. adc_rd = ADC1_read(4);
15. voltage = 5.0 * adc_rd / 1023;
16. sprintf(text,"AN4 Channel ADC Value: %d Decimal\n\r",adc_rd);
17. UART1_Write_Text(text); // Write message on UART
18. sprintf(text,"%0.2f Volts\n\r",voltage);
19. UART1_Write_Text(text); // Write message on UART
20. Delay_ms(2000);
21. }
22. }

 In the Library Manager, don't forget to tick on ADC, UART and Sprintf functions.

 

USART Terminal

 

 

dsPIC30F2010 MikroC for dsPIC UART Example

Overview

The UART is a simple serial communication interface exists in most of micro-controllers. Its protocol is very simple. A build-in UART module of a micro-controller offer a high speed, configurable and reliable data communication. This module doesn't exist in some low-end 8-bit micro-controller for example the PIC16F54 or the popular PIC16F84A. However the programmer can emulate this communication protocol in firmware such Assembly or even embedded C programming language (Software UART) due to its clarity. Some C compilers have their software UART allowing the user access to their build-in function libraries.

 

UART Received ASCII Data

 

This communication interface is used to interact between micro-controller to microcontroller due to its two data wire - Transmit (TX) and Receive (RX). Some peripheral device such as GSM module, Wi-Fi modem (ESP8266), or HMI use UART.

 

MikroC for dsPIC UART Library

MikroC has built-in UART library that supports both hardware and software UART. Hardware UART implements the internal dedicated UART modules of any 16-bit PIC micro-controllers. Some 16-bit PIC micro-controllers have more than one UART interface, UART1, UART2, etc.

These are MikroC Hardware UART Library Routines:

Library Routines

• UARTx_Init
• UARTx_Init_Advanced
• UARTx_Data_Ready
• UARTx_Tx_Idle
• UARTx_Read
• UARTx_Read_Text
• UARTx_Write
• UARTx_Write_Text
• UART_Set_Active

Generic Routines

• UART_Data_Ready
• UART_Tx_Idle
• UART_Read
• UART_Read_Text
• UART_Write
• UART_Write_Text

 

Now let test the UART1 communication interface of the dsPIC30F2010 using the MikroC UART example.

MikroC Source Code:

1. 
   
2. char uart_rd;
3. 
   
4. void main() {
5. 
   
6. UART1_Init(9600); // Initialize UART module at 9600 bps
7. Delay_ms(100); // Wait for UART module to stabilize
8. 
   
9. // U1MODEbits.ALTIO = 1; // Un-comment this line to have Rx and Tx pins on their alternate
10. // locations. This is used to free the pins for other module, namely the SPI.
11. 
    
12. UART1_Write_Text("Start");
13. UART1_Write(10);
14. UART1_Write(13);
15. 
    
16. while (1) { // Endless loop
17. if (UART1_Data_Ready()) { // If data is received,
18. uart_rd = UART1_Read(); // read the received data,
19. UART1_Write(uart_rd); // and send data via UART
20. }
21. }
22. }

 

In the Library Manger Window, Tick on UART. Then build the source code.

 

UART in Library Manager

 

In MikroC IDE, go to Tools -> USART Terminal to open the interface.

 

USART Terminal

 

Enter any characters and click Send, then the MCU will send back the received data. UART requires a precise micro-controller timing. So don't forget to set a correct clock source and frequency.

Let put a character LCD that displays received ASCII characters from PC Serial Port Terminal.

MikroC Source Code:

1. // LCD module connections
2. sbit LCD_RS at LATE0_bit;
3. sbit LCD_EN at LATE1_bit;
4. sbit LCD_D4 at LATE2_bit;
5. sbit LCD_D5 at LATE3_bit;
6. sbit LCD_D6 at LATE4_bit;
7. sbit LCD_D7 at LATE5_bit;
8. 
   
9. sbit LCD_RS_Direction at TRISE0_bit;
10. sbit LCD_EN_Direction at TRISE1_bit;
11. sbit LCD_D4_Direction at TRISE2_bit;
12. sbit LCD_D5_Direction at TRISE3_bit;
13. sbit LCD_D6_Direction at TRISE4_bit;
14. sbit LCD_D7_Direction at TRISE5_bit;
15. // End LCD module connections
16. 
    
17. char txt1[] = "dsPIC30F2010";
18. char txt2[] = "UART Example";
19. char txt3[] = "Lcd4bit";
20. char txt4[] = "example";
21. 
    
22. char i=1;
23. char uart_rd;
24. 
    
25. void main(){
26. ADPCFG = 0xFFFF; // Configure AN pins as digital I/O
27. 
    
28. Lcd_Init(); // Initialize LCD
29. UART1_Init(9600); // Initialize UART module at 9600 bps
30. Delay_ms(100); // Wait for UART module to stabilize
31. UART1_Write_Text("Reply for dsPIC30F2010 MCU");
32. UART1_Write(10);
33. UART1_Write(13);
35. Lcd_Cmd(_LCD_CLEAR); // Clear display
36. Lcd_Cmd(_LCD_CURSOR_OFF); // Cursor off
37. Lcd_Out(1,3,txt1); // Write text in first row
38. 
    
39. Lcd_Out(2,3,txt2); // Write text in second row
40. Delay_ms(5000);
41. 
    
42. Lcd_Cmd(_LCD_CLEAR); // Clear display
43. Delay_ms(10);
44. Lcd_Out(1, 1 ,"PC Terminal:");
45. 
    
46. while(1) { // Endless loop
47. if (UART1_Data_Ready()) { // If data is received,
48. uart_rd = UART1_Read(); // read the received data,
49. UART1_Write(uart_rd); // and send data via UART
50. Lcd_Chr(2, i, uart_rd);
51. i++;
52. }
53. if(i>15) {
54. i = 1;
55. Lcd_Cmd(_LCD_CLEAR);
56. Delay_ms(10);
57. Lcd_Out(1 ,1 ,"PC Terminal:");
58. }
59. }
60. }

 

The LCD shows UART characters, and the MCU will clears it automatically whenever the UART receiving counts reach 15.

Schematic:

Schematic Diagram in Proteus

dsPIC30F2010 Prototype Board Testing:

 

Serial Port Terminal

 

Testing Program

 

UART ASCII Data Receiving

Using the Sprint Library

The mikroC PRO for dsPIC30/33 and PIC24 provides the standard ANSI C Sprintf function for easy data formatting.

Note : In addition to ANSI C standard, the Sprint Library also includes two limited versions of the sprintf function (sprinti and sprintl)
         These functions take less ROM and RAM and may be more convenient for use in                 some cases.  

Functions

• sprintf
• sprintl
• sprinti

 

Since UART terminal accept only binary ASCII codes. Other data types such as array, integer or floating point numbers could not be directly transmitted over this communication protocol. So additional C function libraries is useful for converting non-ASCII characters into a readable ASCII characters.

 

MikroC Source Code:

 

1. double ww = -1.2587538e+1;
2. char buffer[15];
3. 
   
4. void main(){
5. 
   
6. UART1_Init(9600); // Initialize UART module at 4800 bps
7. Delay_ms(10);
8. 
   
9. UART1_Write_Text("Floating point number representation"); // Write message on UART
10. 
    
11. sprintf(buffer, "%12e", ww); // Format ww and store it to buffer
12. UART1_Write_Text("rne format:"); // Write message on UART
13. UART1_Write_Text(buffer); // Write buffer on UART
14. 
    
15. sprintf(buffer, "%12f", ww); // Format ww and store it to buffer
16. UART1_Write_Text("rnf format:"); // Write message on UART
17. UART1_Write_Text(buffer); // Write buffer on UART
18. 
    
19. sprintf(buffer, "%12g", ww); // Format ww and store it to buffer
20. UART1_Write_Text("rng format:"); // Write message on UART
21. UART1_Write_Text(buffer); // Write buffer on UART
22. }

 

We need to set a correct on board clock to 20MHz HS, and also include the UART and SPrint Library in Library Manager.

 

USART Terminal