The Arduino C Programming Language Basics

1. Introduction

In Lab 2 coding in Arduino C language is introduced. Basic 'for' loops, 'while' loops, switch statements, 'do' while, and Boolean operation were all practiced in this lab.
Arduino was also used to convert hexadecimal to decimal. Another task was to wire five LEDs in parallel and to transmit a 5-bit binary number on to the LEDs using a bit mask.

2. The Code and the Results

The following figures are examples of coding in the Arduino C language. 
The code will continuously run until the Arduino is unplugged, because the void loop() function is an infinite loop.

Figure 1. Testing the void loop() function.

Serial.end() is used to end the loop after the first execution. Shown in the figure below, Arduino can also preform arithmetic operations.

Figure 2. Example of using an arithmetic operation and to print 'test' once using Serial.end(). 

Logic expressions can be executed in Arduino as shown below in Figure 3.  The Boolean operator will return 0 for false and 1 for true.

Figure 3. Example using the Boolean operators.

In Figure 4 a 'for' loop was created to print out numbers from 1-9.

Figure 4. Example of 'For' loop. 

The 'while' loop is used to print out numbers from 0 to 9.  The while loop will start at i=0 and increment by 1, then stop executing at i=9. 

Figure 5. Example of 'While' loop.

In Figure 6 a switch statement is used to print out "Now it is 3" for case 3 and "Now it is 6" for case 6. Without the break function in between cases, case 6 would run twice.
The switch statement will execute to case 3 first (switch (3)), then run through the cases below the entry.  Case 6 will then be executed again when switch(6) is called. 
The break statement terminates the cases and returns to the for loop.

Figure 6. Switch statement example. 

Figure 7 contains a 'do while' function.  My example has 'a' incrementing by 3 and the function will declare if the number is even or odd in a while loop for a < 50.

Figure 7. 'Do while' example.

Arduino can convert hexadecimal to decimal using 0x as a prefix. Arduino can also convert binary to decimal and octal to decimal. In Figure 7 0x1000 output is
4096 because Arduino is converting hexadecimal to decimal (1x16^3 + 0x16^2 + 0x16^1 + 0x16^0 =4096).

Figure 8. Converting hexadecimal to decimal.

Task 4:

Use the HEX format (0x.....) (16 bits) to represent the following numbers:

a) 1000 1111 0011 0101 (2) ---> 0x8F35

                                        1000 = 0x8

                                        1111 = 15 = 0xF

                                        0011 = 0x3

                                        0101 =0x5

b) 55 (10) ---> 0x37

                55/16 : remainder 7

                      3/16 : remainder 3

c) 11 (2) ---> 0x3

Task 5:

Convert the following HEX format into Binary:

a) 0xFFFF ---> 1111 1111 1111 1111

                      F=15=1111

b) 0x3210 ---> 0011 0010 0001 0000

                       0x3 = 0011

                       0x2 = 0010

                       0x1 = 0001

                       0x0 = 0000

c) 0xABCD ---> 1010 1011 1100 1101

                         0xA = 1010

                         0xB = 1011

                         0xC = 1100

                         0xD = 1101

Task 6:

A binary number is transmitted to LED pins on the Arduino board. A bit mask is used to retrieve the binary number and store it into an array. A 5-bit binary number is displayed on five LEDs in parallel.
Transmit stored an array of pins that the LEDs were connected to. A for loop was inserted so the binary number could be retrieved using a left shift operator. If both the mask and
transmit[i] were 1 then the LED would be turned on. In Figure 10, 13 was transmitted and the LEDs displayed 01101.

Figure 9. Code to display 13 as a 5-bit binary number on five LEDs.

Figure 10. LEDs lighting up 01101 in binary (13 in decimal).

Figure 10. Code to display 25 as a 5-bit binary number on five LEDs.

Figure 12. LEDs lighting up 11001 in binary (25 in decimal).

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