Very Simple LED Clock Using 16F84A or 16F628A

[pasanrobotics]

**broken link removed**

Its working perfectly.

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[Gayan Soyza]

Nice fully compact design.All with familliar parts.
PORTA drivng the common of the segments directly???????and the rows also same.It can cause load more current through the PIC pin even when its in multiplexing mode.
Thankx for sharing.....

 

[blueroomelectronics]

It is possible with some fancy programming to light only one segment at a time. It's done here with the super probe.
**broken link removed**

 

[pasanrobotics]

It is possible with some fancy programming to light only one segment at a time. It's done here with the super probe.
**broken link removed**

Wow that prob is damn superb. Thanks

 

[bananasiong]

Is there any different of connecting the 7-segment display directly to the output port without any current limiting resistor as compared to drive the 7-segment display with transistor plus current limiting resistor? Since the output current of the PIC's is only 25 mA, it won't burn the LED right?

 

[picasm]

Is there any different of connecting the 7-segment display directly to the output port without any current limiting resistor as compared to drive the 7-segment display with transistor plus current limiting resistor? Since the output current of the PIC's is only 25 mA, it won't burn the LED right?

I do not fully trust the "25mA port limit" that is often referred to in various data sheet documents.
I think that what the manufacturers mean is that it must absolutely never exceed 25mA (or about 200mA combined for all ports) - but it is taken by users to mean that it is automatically current limited so that you do not need resistors - which is wrong.

As I see it, the only way that you can get away with exceeding the 25mA limit is to use multiplexing to reduce the average port current, which is ok as long as your multiplex software does not latch-up due to some software error.

 

[3v0]

In regards to the Mondo SuperProbe not using limiting resistors. The author points out that SuperProbe is a study in doing the most with the fewest parts. Possibly because it had to fit in an existing probe case.

The Superprobe project was designed to see how much could be done with a PIC chip and just a few parts.

If you have the room use limiting resistors.

 

[delokaver]

**broken link removed**

Its working perfectly.

Go here for more Details

is there is any PCB artwork for this clock ??