Help needed

[nikki81]

Thank you very much for your help but ive spent 5 more hours today taking the components off the board testing each one then tinned the traces on the board and checked each trace with my meter then refitted all the components and still its dead so am going to quit before i waste anymore time with it.

 

[(*steve*)]

It's always a good idea to have a LED on the board, controlled by the uC. That way you can load test programs to (initially) just flash the LED.

If you're clever, you can have a diagnostic program that tests the board and flashes error codes on the LED if it finds something.

Even cleverer is to have this run each time power is applied (before running the regular program).

But just a simple flash the LED program will tell you if you're programming the chip, if power is applied, etc.

If you don't have a LED on the board, you could temporarily connect one up to some otherwise unused pin.

 

[CocaCola]

I regularly use LEDs as debuggers, if you have the extra pins you can set the LEDs to go on and off (bink) at certain stages of the program... This will give you a clear visual of where the program is at any given moment and provide a visual of the program actually running... Very handy, and pretty much want many of the debugger interfaces do with text outputs...

 

[nikki81]

i would love to put a led on to see what is happing but i don't know how to write code and not sure how to add the led. how would you add a led to this circuit ?

 

[nikki81]

will this work ?

*** its pin 22 not 19 that ive got free ***

 

[nikki81]

ive remade the whole thing on a new pcb and now when i plug it in to the pc it is detected and i can control xbmc but the lcd has just got a line of blocks on the bottom

 

[(*steve*)]

will this work ?


*** its pin 22 not 19 that ive got free ***

Yeah, that will work. It is more common to have the anode on the output pin and the cathode to ground via a resistor. That way you will see when the pin goes high. This is a good idea because if the pin is an output it will normally be low unless you tell it to go high. That means the LED going on requires the program to do something.

However if you're not in a position to write software, then there's not much point.

ive remade the whole thing on a new pcb and now when i plug it in to the pc it is detected and i can control xbmc but the lcd has just got a line of blocks on the bottom

Well, either the board is still wrong, the code is wrong, or the LCD is connected wrong.

Not that this helps you much

The fact that some functions are working confirms you have programmed the device and that your board is at least partially correct

 

[CocaCola]

The fact that some functions are working confirms you have programmed the device and that your board is at least partially correct

Yeah, I suspect that we can confirm the chip is programming, and since the author claims it works as written, we are now at the point of finding the fault on the PC board or an improper connection...