Apologies if this question has already been asked or it's too simple.

I am starting out on Microcontrollers and I have been looking at the following:


Now, I have skimmed the data sheet and have the following Pin schematic:

enter image description here

Should I therefore connect the power supply (battery powered) to pin 20 & 19?

  • 2
    \$\begingroup\$ Yeah, power to 20 and ground to 19. I'd also ground pin 8. I'm not sure if the RESET is active HIGH or active LOW, so also make sure you have a pull up/down resistor connected to that guy. \$\endgroup\$ – Nick Williams Jan 23 '15 at 13:53
  • \$\begingroup\$ Check this out \$\endgroup\$ – Vladimir Cravero Jan 23 '15 at 14:01
  • \$\begingroup\$ Although, you did not ask this, but it might not work right away when you power it up. I did not work with this part, but if it does not have an internal clock, and you program it to be externally clocked - you must also connect an external oscillator to pins 9 and 10. \$\endgroup\$ – Nazar Jan 23 '15 at 15:12
  • \$\begingroup\$ @Naz I am confused. Why so? \$\endgroup\$ – Phorce Jan 23 '15 at 15:18
  • 1
    \$\begingroup\$ Check out the brief specsheet for this family. It does contain internal clock (last page), so make sure when you program the chip you set the clock registers to use internal clock. If the internal frequency is too slow for you, you will need an external oscillator (or some other source clock) to drive your chip. You need to find the detailed datasheet for your particular part - it will explain everything in detail. \$\endgroup\$ – Nazar Jan 23 '15 at 15:33

As you can see from the diagram Pin 20 is V+ and therefore that is where your positive power supply should go, also Pin 19 and Pin 8 are 0V so you will need to wire these to the ground of your power supply.

The rest of the pins are inputs or outputs or other functions which can be specified in the code you write for the chip. The resonator pins (Pin 9 & Pin 10) is where you would connect the clock source for the chip which would give it the timings it needs (not necessary if it's got an in built oscillator).

V+ is always where you connect the power supply unless specifically stated otherwise (not likely) and 0V or GND is where you connect your power supply's ground.

  • \$\begingroup\$ Thank you very much. Although I feel kind of stupid, I just wanted to clarify that this was correct. Getting my head around the simple problems I'm sure will help me in the future. \$\endgroup\$ – Phorce Jan 23 '15 at 22:56

Its clearly showing the 20th Pin as +v and 19th Pin as 0V.

so no problem you can clearly connect to the pin without any more thinking.

  • 3
    \$\begingroup\$ pin 8 should be gnd too. \$\endgroup\$ – Nazar Jan 23 '15 at 15:08

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.