Hi,
My knowledge are limited in electronic, I am coming from the world of software and recently bought a BeagleBone Black. I would like to knwo if I could interface a 74LS02 to the BeagleBone Black.
I plan to connect Vcc and Vss of the 74LS02 to the 5V Vdd output and Gnd of the Beagle and use the GPIO pins to command the logic inputs. My problem is that I don’t know if I can plug the 74LS02 without components such as resistors, in order to limit the current flowing through components. I wouldn’t damage the board.
The result of the logic operations should return to some GPIO pins configured as inputs.
Thanks in advance for your answers
Hi,
My knowledge are limited in electronic, I am coming from the world of
software and recently bought a BeagleBone Black. I would like to knwo if I
could interface a 74LS02 to the BeagleBone Black.
Not that chip, no.
I plan to connect Vcc and Vss of the 74LS02 to the 5V Vdd output and Gnd of
the Beagle and use the GPIO pins to command the logic inputs. My problem is
that I don't know if I can plug the 74LS02 without components such as
resistors, in order to limit the current flowing through components. I
wouldn't damage the board.
It's not current limiting, it's what the voltage can cause in the
lower voltage chip.
However, you might want to investigate other chip families such as the
74HCT, 74AHCT, 74AC, etc, which have the exact same functionality and
may run from the 3.3 volts found on the BBB. Those inputs can be
safely connected to the BBB (except the A/D inputs), and the outputs
can safely drive an input pin on the processor.
What you're looking for is a specification on the 74xxx chip that
allows operation at 3.3 volts.
Stick with a low voltage chip family and shifting between 5 volt and
3.3 volt systems goes away.
The older microprocessors used 5 volt logic, the newer families tend
to use 3.3 volts for all the input/output.
Harvey