Use code based timing methods to calculate reaction times. More...

Functions
def	Lab0x02_A.onButtonPressFCN (IRQ_src)
	Callback function for the button press. More...

Variables
	Lab0x02_A.pinC13 = pyb.Pin (pyb.Pin.cpu.C13)
	Pin attribute for blue user button. More...

	Lab0x02_A.pinA5 = pyb.Pin (pyb.Pin.board.PA5, mode = pyb.Pin.OUT_PP)
	Pin attribute for LED. More...

	Lab0x02_A.ButtonInt = pyb.ExtInt(pinC13, mode=pyb.ExtInt.IRQ_FALLING, pull=pyb.Pin.PULL_NONE, callback=onButtonPressFCN)
	Callback interrupt attribute. More...

int	Lab0x02_A.S0_INIT = 0
	Initial state.

int	Lab0x02_A.S1_WAITING = 1
	State for pause between LED blinking.

int	Lab0x02_A.S2_LED_ON = 2
	State for LED on-time.

bool	Lab0x02_A.buttonPress = False
	Variable to keep track if the button is pressed or not.

	Lab0x02_A.zeroTime = utime.ticks_us()
	time to compare to in calculating elapsed time since a certain action

	Lab0x02_A.ledTime = random.randrange(2000000,3000000)
	Off time between LED flashes.

int	Lab0x02_A.ledPeriod = 1000000
	Time interval for LED to stay on.

int	Lab0x02_A.state = 0
	State machine state variable for mini FSM.

list	Lab0x02_A.rxnTimes = []
	List to hold the reaction times (later will be averaged)

int	Lab0x02_A.avgRxnTime = 0
	Variable to display the average of the reaction times.

	Lab0x02_A.currentTime = utime.ticks_us()
	current time in microseconds

	Lab0x02_A.elapsedTime = utime.ticks_diff(currentTime, zeroTime)
	elapsed time since zeroTime was last reset (microseconds)

bool	Lab0x02_A.calculate = True
	Should the program calculate a reaction time?

	Lab0x02_A.thisRxnTime = elapsedTime
	current reaction time (microseconds)

Detailed Description

Use code based timing methods to calculate reaction times.

Using the Nucleo L476RG board and code/software based methods, the reaction time of a user pressing the B1 button will be measured when the LD2 LED turns on. For Part A of this lab, the LED is turned on and off using the high() and low() methods for a pin. The LED will be on for 1 second each time (controlled through a state machine), and will turn off for a random time between 2 to 3 seconds. Once the user sees the LED flash on, they will press the button, triggering a callback and starting the sequence of calculating a reaction time. Although this method works, it is not the most effective or accurate. Part B of the lab covers a hardware based solution that improves upon Part A.
See source code here: https://bitbucket.org/ryanmclaug/matt_ryan_shared/src/master/405_Lab0x02/Lab0x02_A.py

Figure 1. Overall program FSM.

Author: Ryan McLaughlin; Matthew Frost

Date: Originally created on 04/22/21
Last modified on 04/27/21

Function Documentation

◆ onButtonPressFCN()

def Lab0x02_A.onButtonPressFCN ( IRQ_src )

Callback function for the button press.

When the button is pressed, the onButtonPressFCN function will be called. In the constructor, buttonPress is set to False, such that when it is pressed, it switches to True. Likewise, since the button is set to detect both rising and falling edges, the button returns to False when released. Based on use of the not operator.

Variable Documentation

◆ ButtonInt

Lab0x02_A.ButtonInt = pyb.ExtInt(pinC13, mode=pyb.ExtInt.IRQ_FALLING, pull=pyb.Pin.PULL_NONE, callback=onButtonPressFCN)

Callback interrupt attribute.

When a rising or falling edge is detected by the button, the interupt will be triggered.

◆ pinA5

Lab0x02_A.pinA5 = pyb.Pin (pyb.Pin.board.PA5, mode = pyb.Pin.OUT_PP)

Pin attribute for LED.

Similar to pinC13, but for the output LED.

◆ pinC13

Lab0x02_A.pinC13 = pyb.Pin (pyb.Pin.cpu.C13)

Pin attribute for blue user button.

The blue button on the board serves as the main user input interface, and therefore needs a pin assignment.

Functions