hi i am final year student of electrical engineering and doing a project on 8051 microcontroller. in this project,i have to interface the 8051 to maltab for real world data.i successfully complete the interfacing and communicate serially on proteus.data which is transfer from 8051 to matlab is not accurate when i send more than one character.in single character, matlab does not show any data.plz help me,how to solve that problem as i am using 8051 first time.
one other ceramic cap (rest all being electrolytic) present in the power supply unit, one end connected to gnd and the other to pin 40 for Vdd, dist between that pin and pin 40 is almost 1.5cm "a wire/trace is not a wire"
PLEASE do not use pin numbers, I GUESS "pin 40" is Vdd. (I have not used DIL for ages) how long is the trace from the other end of the cap to the gnd pin "gnd is not gnd"
rest all being electrolytic does that mean aluminum or tantalum?
just to check, solder a ceramic 10-100nF directly to the gnd and Vcc pins on the uC
What does a scope set to AC 1V show on the Vdd AT THE uC?
Erik
you, probably, should post at 8052.com instead
I'm sorry I didn't understand the statements, "a wire/trace is not a wire" and "gnd is not gnd".
Aniket
When all you have is DC, a trace on the PCB can be seen as a resistor with a very low resistance.
When your current consumption is pulsed, which it is in a clocked digital circuit, then the PCB wires are no longer just resistors. They behave as if they have capacitance and inductance. So you need to take care - for example reduce the current pulsing in the wires by having decoupling capacitors as close at is possible to VCC and GND of all your chips.
If you have digital inputs unconnected, the radio-frequency energy radiated from other signals can be enough to get an open digital input to jump randomly between zero and one.