Problems with blink LED

Tip / Sign in to post questions, reply, level up, and achieve exciting badges. Know more

cross mob
lock attach
Attachments are accessible only for community members.
Anonymous
Not applicable

 Hello.

   

I'm trying launch my PSOC4 CY8C4245AXI-483, with simple programm blink LED. It's working but bad and very wierd. 

   

Video here https://www.youtube.com/watch?v=_1OWf3EIq4M 

   

Also I attached scheme.

   

Power is 3.3V. I tested fiew controllers, and they work same. 

   

I tried use program from example, and have same problem. Voltage on the pin don't go down to GND. 

   

May be, anybody know where I should look troubles?

   

Regards.

0 Likes
28 Replies
Anonymous
Not applicable
        Hi Trouyan2   
How was set the LED drive pins?   
Drive mode is important   
strong drive or open drain, drive low is better.   
0 Likes
Anonymous
Not applicable
        Look at blinking LED example of Pioneer Kit.   
That has same circuitry same as yours.   
Have a cathode drive LED.   
If not have the kit, down load the documents and take a look.   
0 Likes
Anonymous
Not applicable
        Ah, I forgot the picture   
0 Likes
Anonymous
Not applicable

 Yes I'm using strong drive. And I tested example with PSOC Creater and got same result. =(

0 Likes
Anonymous
Not applicable
0 Likes
Anonymous
Not applicable
        Oh, my browser, safari become get wrong to uploading.   
IE9 also, what is going on?   
0 Likes
Anonymous
Not applicable
        Ok Trouyan2   
Upload your project bundle, I will be check it.   
Minimaled design is better, LED part only but has a trouble.   
0 Likes
Bob_Marlowe
Level 10
Level 10
First like given 50 questions asked 10 questions asked
        Can it be that you mistook pin 2 (Vcc) and pin3 (blue)?   
   
Bob   
0 Likes
ETRO_SSN583
Level 9
Level 9
250 likes received 100 sign-ins 5 likes given

Some thoughts, questions -

   

 

   

1) Your Vcc is "stiff", no voltage droop when LEDs come on, restarting processor ?

   

2) When you see LED pin not going to ground, what voltage do you see when it

   

is logic low ? Keep in mind it will not go compeletely to ground because of Vol spec,

   

and is not a super low RDSon output . With 1K, LED drop of 2V, you would expect

   

Vol (LED on) to be ~ .2 V.

   

3) You have confirmed 1K LED R's are 1K ?

   

 

   

Regards, Dana.

0 Likes
Anonymous
Not applicable
        As I look your circuit, "open drain, drive low" drive mode is also usefull,   
for your cathode drive LED, it's not depend Vdd of PSoC.   
Would you try it.   
   
Mostly wanted information is wave form of LED pin.   
Would you show it.   
0 Likes
lock attach
Attachments are accessible only for community members.
ETRO_SSN583
Level 9
Level 9
250 likes received 100 sign-ins 5 likes given

Open Drain is irrelevant to driving LEDs to Vssa. Just set up

   

output as strong drive to achieve a good switch to ground.

   

 

   

See attached.

   

 

   

Regards, Dana.

0 Likes
Anonymous
Not applicable

 Oh, so many post, thank you all for your comments.

   

To PSoC73

   

Project in attached file. I tryed "open drain, drive low" and also negative result.

   

To Bob Marlowe

   

No, I don't mistook pins. I reviewed it some times.

   

To Danna

   

1. All okey with input voltage. It haven't droop.

   

2. I see 0.9 V and about 3 V on the LED pin (instead of about 0V and 3.3.V)

   

3. It's most interesting question, and answer bellow:

   

To All

   

I read in datasheet that max current on the pin is 25mA. Before 1kOhm I used 360 Ohm. 3.3V/360Ohm=9mA. But if look to Dannas image: I had Current :"4mA source, 8mA Sink". May be it killed ports?

   

I tryed set Current as on Dannas image:  "8mA source, 25mA Sink" , but got error : "Pin 3 does not support SIO":

   

Regards.

0 Likes
Anonymous
Not applicable

 Project in attached file.

0 Likes
Anonymous
Not applicable

 TRY EXCEPT CHROME, BUT IE, SAFARI, FIREFOX is OK 

0 Likes
Anonymous
Not applicable

 Anyway, How many voltage at the pin when ON and OFF ? 

   
        
0 Likes
Anonymous
Not applicable

 LED polarity is OK? HaHa

   

LED is still alive? HaHaHa 

0 Likes
Anonymous
Not applicable

There are 0.9V and 3V at the pin. But some time it changing.

   

LED is good and connection correct.

   

Regards.

0 Likes
lock attach
Attachments are accessible only for community members.
Anonymous
Not applicable

Trying again attach the project.

0 Likes
Anonymous
Not applicable

 If the voltage 0.9V and 3V, so LED wiring is something wrong 

   

Definitely ! 

0 Likes
Anonymous
Not applicable

 It's Blinkin Baby ! 

0 Likes
Anonymous
Not applicable

 I read in the datasheet that max current on the pin is 25mA. Before 1kOhm I used 360 Ohm. 3.3V/360Ohm=9mA. But if look to Dannas image: I had Current :"4mA source, 8mA Sink". May be it killed ports?

   

I tryed set Current as on Dannas image:  "8mA source, 25mA Sink" , but got error : "Pin 3 does not support SIO":

   

Regards.

0 Likes
lock attach
Attachments are accessible only for community members.
Anonymous
Not applicable

 This is probed form,

   

LED's Vf=3.1-3.3V(white), series R=300ohm 

   

Of course period is shorten.

   

Well, Tell me what was wrong . 

0 Likes
Anonymous
Not applicable

0 Likes
Anonymous
Not applicable

 Movie file can't upload 

0 Likes
ETRO_SSN583
Level 9
Level 9
250 likes received 100 sign-ins 5 likes given

My error, outputs speced to 8 mA, not 25 mA. 25 mA is only for SIO pin.

   

 

   

The equation you use for LED resistor              

   

 

   

       Rled = ( Vddmin - Vledmax - Vohmax ) / Iled

   

 

   

Vohmax is speced at 8 mA, .6V, Vdd of 3V. This will give you worst case value. You are limited

   

to 25 mA/pin, but there are no curves for Vol vs Iol for you to design to. There may be a spice

   

model for output, you can check website for that. Vledmax varies a lot LED to LED, so consult

   

your datasheet.

   

 

   

If you want more current drive two pins per LED, eg. parallel them.

   

 

   

Regards, dana.

0 Likes
ETRO_SSN583
Level 9
Level 9
250 likes received 100 sign-ins 5 likes given

"2. I see 0.9 V and about 3 V on the LED pin (instead of about 0V and 3.3.V)"

   

 

   

1) The .3 V difference between output Voh (LED off) and Vdd due to ohmic drops of other

   

on LEDs and the way you are distributing power ? What is your ground reference.? When

   

LED pin off it should pull to the Vdd rail. Measure pin to Vddd to see if it is consistent with

   

pin to Vssd.

   

 

   

2) The .9V Vol (Led on) could be legit, all depends on Vled, Rled, Iled........Again you could

   

consider paralleing 2 outputs to get more Iled and/or lower Vol.

   

 

   

Regards, dana.

0 Likes
Anonymous
Not applicable

 Thank you all. 

   

I think the problem in the board, because I assembled new board and now all working.

   

Thank you very much.

   

Regards.

0 Likes
Anonymous
Not applicable
        Ah, Very nice to hear it   
Everyone walk a similar way.   
The first step is LED blinking!   
Cheers   
0 Likes