8055 output test question (need some info)

Kits PC Related Projects
1

ok so i put the card together and the inputs work fine. the outputs are a different story.
when i plug it in to the usb led8 lights up like it should, and when i put a battery on the CLAMP i can get an external led8 to light.(when i plug in the usb)
but when i run the output test, no leds ever light up on the output.
when i put it together the output test never worked, ever.

is the output test supposed to light leds 1-8 w/o a battery attached?
and why does led8 light if the demo program wont light it?

the velleman manual does not tell you what should happen when you
run the output test. it just tells you to do it with no regard to the results

so i need to know how one of these cards is supposed to act.
if some chips are messed up, how do i know that i did it?
or was it corrupt from the get go?

2

No battery is needed to run the test. In the output test there is a “running” light. All the output LEDs are lit sequentially.

After plugging the unit to the USB socket of the PC the LED LD8 should give three flashes and stay OFF. If it stays ON then the card is not detected by the PC.
In this case check the soldering and check that all the ICs are right position.

By the way: Do the other functions of the demo software work OK? E.g. does “Set All Digital” turn all the LEDs LD1 to LD8 on and “Clear All Digital” " turn all the LEDs off?

3

thanks for the info on how it should act.

as for the demo, “Set All Digital” does not turn LED1-8 on.
LED 1-8 is always off during the demo software.

ic2 & ic4 are ok. i switched them and the input is still good.
yes, the other ics are in right.

i will double check the soldering that seems like a likely place to start.

thanks

4

i just read a post that seems to act similiar.
his solution was to change from address 0 to somthing else.

i will give that a try too.

5

still no go on the outputs.
i will check the components.

how do i test the processor?

6

When the power is turned on (the USB cable plugged in) the LED LD8 should give two flashes if the program of the processor starts. The third flash indicates that the unit is detected by the PC.