Measuring

This is the first part where the LED on the board is connected:

Measuring the voltage high level on the output pin RD0:  4.84 volts

Measuring the voltage low level on the output pin RD0:  1.6 mV

Measuring the current high level on the output current with the LED and resistor on pin RD0: 4.05 mA

Measuring the current low level on the output current with the LED and resistor on pin RD0:  0.0 mA

This is the second part where all the LEDs on the board on are disconnected

Measuring the voltage high level on the output pin RD0:  4.88 volts

Measuring the voltage low level on the output pin RD0:  0.0 mV

Measuring the current high level on the output current with the LED and resistor on pin RD0: 0.0 mA

Measuring the current low level on the output current with the LED and resistor on pin RD0:  0.0 mA

• Note: no current running due to no ground

This is the third part with an LED directly connected from pin RD0
to ground

Measuring the voltage high level on the output pin RD0 with a LED connected to ground:  2.4 volts

Measuring the voltage low level on the output pin RD0 with a LED connected to ground:  0.0 mV

• Note: must ask why the voltage drops to this low value

Measuring the current high level on the output pin RD0 with a LED connected to ground: 27.75 mA 

Measuring the current low level on the output pin RD0 with a LED connected to ground:  0.00 mA

• Note: here we fear that the chip might burn off due to the high current. The maximun operation limit is 20mA

Explore the topic

First we will get an overview

Make a program to set the pin0 on port D to high, and afterward to low. For measuring we will use an oscilloscope.

a.       We will note the levels (both voltage and current) when it is high and when it is low. According to the datasheet ( page 21 ) it states that the pin RD0 is TTL buffer. Due to that we can see on page 247 that the high output will minimum be 3.3Volts when we use I_OL = 8.5mA and V_DD = 4.5V. For the low output the voltage would be a maximum of 0.6 when we use I_OH = -3mA and V_DD = 4.5V.

b.      The total current specification states that there can at maximum run 200 mA on portD and portC combined

c.       No more than ±20 mA can run through a single pin