Inchworm ICD2 users please!

Hi,

I have built an Inchworm ICD2 using the schematics and hex posted in this forum.

It is not working.

I will describe.

877A running - as I am getting a 5ms (almost) squire wave in the CTS pin of its serial output connector. (ICD requesting MPLAB "Clear To Send" ,right?)

serial communication parts ok as I have checked transmition and reception using my own serial port programe - TX and RX OK

My computer serial port ok because my original Microchip ICD works perfectly
on serial mode and USB

If I connect this ICD through a serial port sniffer programe ,both behaves same.

But MPLAB never shows any symptom of such a device in the serial port !

"Connect failed"

What to do?

I am using MPLAB 7.4 and firmware on 877A

Anybody who have done this Inchworm please provide the confirmed schematics and hex file please.


thanks for reading

picstudent

Try this.

Is it working now...

I hope so. I think this was the same thread as on ElectroTech. The firmware with OS fixed that one.

blueroomelectronics said:

I hope so. I think this was the same thread as on ElectroTech. The firmware with OS fixed that one.

Click to expand...

The firmware with OS you send me before started things working.

But still I have one problem.

Actually I am doing my own PCB now.But I constructed 3 units(I need three in my work) using the pcb design posted in this forum.

All three shows the same symptom, ie it wont get connected sometimes.PIC running ,but MPLAB fails to detect.

There are few resistors in the Voltage sensing dividers in the circuit where 1% resistors prescribed I think. I am using normal resistors there which were available with me.
Is it that much critical?

Once it gets connected it will be okay until we power off.

If we switch off the power it may take take many trials to get connected.

May be some problem with components. So far not able to locate correctly.

It would be helpfull if we know how MPLAB 'detects ' and arrive this 'connected' conclusion.

Thanks a lot.

When connected it works perfectly like my Microchip ICD in serial mode.

picstudent

@picstudent : Why don't you try replacing with 1% resistors and see if it works ?

That's the only problem you are facing right ?

And did you say the Inchworm behaves EXACTLY like the ICD2 from Microchip ?

vsmGuy said:

And did you say the Inchworm behaves EXACTLY like the ICD2 from Microchip ?

Click to expand...

defenitly! to the extend I can test and use this device.


You can confirm with other more experienced users also.

Limitations may be there regarding different voltage devices and all. I am not sure.

If you want to use 3.3Volt devices using this clone may not be possible.

Just do it and see man This is not a billion dollar investment after all.

Whatever may be the limitations, if you are not having an ICD2 already ,an ICD2 clone is worth the investment for your PIC work!

picstudent

Aside from no output buffers (easy to build & troubleshoot, low cost) and the lack of USB on the classic Inchworm (the Inchworm+ can be uprated with Unicorn to a superfast USB ICD2 clone)

It's as simple an ICD2 as can be and does not require any special power supply. As for 3.3V you really should have some sort of buffer logic.