K8055 How can I work digital outputs?

Kits PC Related Projects
1

Hi there,

I’ve bought the 8055 and I’m experimenting a little with it.
Works like a charm, but I don’t get why there’s only 0,58V coming out of the digital output…
Can anyone explain?

Thanks.

2

Perfectly normal, outputs are open collectors.
See this topic:

[url]Open collector contacts or outputs, what are these things?]

3

Alright…
But I’d rather get 5V from the output.
I’ve played around a bit with a voltage meter and if I lay a connection from Out8 to GND I get 4,8V
Could I safely remove the resistor and LED and draw a jumper from Out8 to O8?

Thanks.

4

In order to get 5V or 0V from the outputs, you will have to provide a pull-up resistor from the output to the +5V (e.g. 10K)

5

But won’t I blow up the board?

6

Not if you do it correctly.

7

hi

what you mean by: ( pull-up resistor from the output to the +5V (e.g. 10K) ) and how/where i connect the resistor .

thanks

8

Connect a resistor from each digital output to the +5V of the card…

9

hi sir,
i have k8055, after i assembled and read some in the forums, i did as this:
i used power supply 5 volt, connect -5v to the GND , connect +5v to CLAMP, then connect 10 k R1 from outpu1 1 then connect R1 to led (-) and connect from CLAM to (+) of the same led. (is what i did is ok)
it is working fime but what i want to know if i want to use relay inted of led, do i have to use R1(with 10k). i test the volt on the led it arround 1.8 v, but i need more volt to operate the relay (5 volt or 12 volt).

thanks alot

10

For a relay, you need to supply an external voltage, as the on-board +5V is not capable of supplying the necessary current.
http://www.velleman.be/images/tmp/K8055_relais.jpg