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Lab 4 - Calculations

<^< 3. Connection Point | Course Index | 5. Loop >^>

Modern microcontrollers, like the PIC, are able to do simple mathematical tasks with 8-bit numbers really fast. When the calculations get more complex or the numbers rise above an 8-bit value, then this is possible too but it adds to execution time drastically. Flowcode lets us use complex calculations on up to 16 bit values in programs and takes care of all the complexity behind it. We do however, have to take into account that this will slow the PIC down.

EB006 Options	Setting	Jumper settings (EB006)	Jumper settings (HP488)
Power supply	External, 14V	J29: PSU	J29: PSU
PICmicro device	16F1937
Programming method	USB	J12,13,14: USB	J20: USB
Clocking method	XTAL	SW2: XTAL	S2: XTAL
R/C clock speed
Xtal frequency	19 660 800 Hz
LVP Jumper selection	I/O Port	J11,16,17: I/O Port	J15,16,18: I/O
Port A E-block
Port B E-block	LED board
Port C E-block
Port D E-block
Port E E-block

Build > Project Options... > General Options	Build > Project Options... > Configure
Options Setting Clock speed 19 660 800 Hz Simulation speed As fast as possible	Options Setting Device 16F1937 RC/XT XTAL Watchdog timer Off

Output, binary code training, what are variables and how are they used, calculations on an 8-bit microcontroller.

LED’s, logic output levels, Calculations on an 8-bit microcontroller

Construct the system shown from E-blocks.

In the course navigate to the ‘Flowcode step-by-step’ and review the Digital Inputs (section 3) to get more info on how to use variables and sections 4, 5 and 6 on Calculations. In the main course you will find interesting info on where variables are stored in the PIC.

Make sure to use the 'Help' menu and function in Flowcode to get more info on the calculation and variables possibilities.

During these exercises you are going to send different 8-bit codes to Port B of your Microcontroller. You'll also learn how to use variables and perform calculations on 8-bit numbers.

16-bit Float variables can also be used, although these are not discussed in this course.

Letter	Meaning
L	Lab x
B	Basic complexity
I	Intermediate complexity
E	Expert complexity

L4-B1

Load the value '1' into a variable that is called 'counter'

L4-B2

Display the value of the variable 'counter' on the LEDs

L4-B3

Multiply the value of 'counter' by 2 and display on the LEDs. Do this by adding a calculation icon with: 'counter = counter * 2'

L4-B4

Repeat these steps infinite and add a delay of 300msec between these steps. What do you see? How do you explain this. (This is called a ‘running light’.) Write the explanation you have for this down on a piece of paper.

L4-B5

Replace the 'multiply by 2' with this instruction; 'counter = counter + 1'. What do you see now? You just programmed a binary counter.

L4-B6

Display the result of the following calculations on the LEDs of Port B, using Flowcode and the calculation icon. Convert from binary to decimal on a piece of paper to check if the binary result is correct.

• 45 + 52
• 45 AND 52
• 45 OR 52
• NOT 45
• 45 XOR 52
• (1+3)*(6/2)
• VAR2 = VAR1 * 3 (where VAR1 is filled first with 18)

<^< 3. Connection Point | Course index | 5. Loop >^>