Quote Originally Posted by ngeronikolos
...using max6953 & 4 5x7 led dot matrix (common anode) controlling by a pic 16f84a.
...I try to controll the driver via the ltp of my computer without any success.
The software I have already
installed on my pc is working property
(I checked with a osciloscope the scl&sda that the computer send).
And what does the PIC do?
If you are trying to control the MAX6953 from your PC this is the wrong Forum category to ask for help.

So the problem is with my circuit.
I use Cset=27pF ceramic to the osc pin21,do you think that this would
be the problem?The cable lenght is 0,5m between the pc and the driver.I
am trying to controll the max6953 via the ltp with the software free
from maxim site. I find from the data sheet of the product the waveform
at the pin 21(osc)(Cset).In my case,while my max6953 is connected to 4
dot matrix's leds&to ltp port of my pc,the signal amplitude is too
low(it seems to me like noise).I can not see that waveform with my
osiloscope.Do you think that the Cset cause the problem?Why I can not
display what I send to it from my pc?What can I do to solve my problem?
Again you are talking about a PC, what does the PIC do?

Could you post your schematic?

And please be as precise as you can, see: this