Simple question-programming pins

limaD_07

New Member
cube shem.PNGSo just to be different from a cube im building a triangle LED cube. I was constructing a circut that i was going to use and i think i have finished! (Please tell me if somthings wrong) However i dont know which pins on the 28x2 are the programming pins? can sombody please help with what i need to program the cube?
 

premelec

Senior Member
See manual #1 about page 11 - pin6 input pin 7 output as far as I can tell - i can't resolve your picture well enough to see what's there...
 

nick12ab

Senior Member
The PR and ST pins on the Genie chip are Serial In and Serial Out respectively.

Now time to comment on the rest of your circuit:
  • The voltage regulator is connected backwards. The input is also connected to the output.
  • You have no 'bulk capacitor' on the output of the voltage regulator (normally 100µF).
  • Only one of the two 0V pins on the microcontroller are connected.
  • You are using NPN transistors as high side drivers - that will not work.
  • The 220 ohm resistors on the transistor bases seem to be low for base resistors - are these really the required base resistors?
Also an LDR is not an on/off motion sensor but I've kept that off the list above because you're probably just using it to represent a motion sensor.
 

limaD_07

New Member
Thanks heaps i have adreesd most of the promblems however why will the npns not work? I was given this design by my teacher he said that was what i should work with? And yes the LDR was a place holder hahah
 

Goeytex

Senior Member
however why will the npns not work?
When the load is on the emitter side of an NPN transistor it is called an emitter follower, meaning the voltage at the emitter will follow the voltage at the base. So if the base is at 5v the emitter will be at 5 volts. It might be ok for a single LED that needs less than 5v but not for a string of say 4 leds that will need 12v. To get 12v on the emitter, you will need 12v on the base.

A better way is to use the NPN as a low side switch where the Emitter is connected to ground and the load connects between the collector and the positive supply.
 
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