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Since you used an air coil there is no problem with coil saturation.
The first step would be to insert a push-pull stage made out of two bipolar transistors between the MC34063 output and the mos-fet gate. This will greatly improve your mosfet switching characteristic.
Once I saw a car laptop...
MC34063 controller was designed to drive bipolar transistor as an external switch. From your post I understood that you used a MOS transistor. It is possible to use a mos but with special cautions. Have you took care of that?
Simply replacing the bipolar with a mos causes turn off problems...
You might be right about D6 and T2, but D7 is always forward biased and I cannot see any advantage from using it there.
Anyway, on my ICD2 I removed them both and until now it works with no problem.
When I removed D6 I wasn't sure If it's correct what I'm doing or not, so, I tried it...
you cannot remove T3 completely. If you remove it, you will apply the programming voltage of around 13v directly to line RC2. As a result the internal clamping diode will be forward biased and it will inject the 13v into the 5v supply.
Completely unwanted I might say.... :)
On the other hand...
abdalla,
The line named RC2 pulls the "target MCLR" to ground.
T3 acts like a switch which opens when it's emitter is pulled down to ground. You can see in the schematic that the base is connected to VCC therefore when the emitter is pulled to ground by the RC2 line the B-E junction is...
Today I got to check the icd2 I built on a different computer. The bad news is that it behaves exactly the same. The same blinking led when I connected it and after a reset it works normally. Can anyone help me with this problem?
Thank you
Hello Nandulal,
I already tried both hw versions (with and without external reset) and the behavior is exactly the same. I thought that my problems appear due to the poor quality of the circuit (it's built on a breadboard).
I did not tried the circuit on another computer because I don't have...
No. I used the FT 232 chip on the old version. I have the problems with the PIC18F4550 part of the design.
The serial section together with the FTDI chip works fine. Of course the usb ports are not connected together :).
If I plug in the FT232 chip the board works great it has no problem, but...
Hello,
I just built the usb icd2 presented on this thread. But I have problems with it. I cannot make it connect normally to windows. It's very unstable. Immediately after I plug it in the usb led starts flashing. If I apply a manual reset on the MCLR pin it connects and works normally. I...
The easyest way to control the LCD is to have a small pic as a "LCD driver" and also act as some kind of master wich should be able to interogate the other pics via spi or other kind of bus for the measured values. But this aproach has the disadvantage of having a complicated hardware.
Another...
I just built myself an ICD2 clone based on the schematics found on this forum and on the internet. It's not the full speed USB but it still uses the USB (virtual com port) mainly for the advantage of having the 5 volt supply. The design is made entirely with smd components. If you are interested...
icd2 problem
Hello,
I just built an ICD2 debugger (the USB version from Lothar Stolz).
The problem is that i can't connect to it from MPLAB. I tested the USB to serial part with a serial port monitor and everything seems to be ok. I keep getting the following message:
ICD0019...
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