Can't connect to the PK2-LITE

[Mickster]

FWIW to the OP, I originally built a feng3 JDM (**broken link removed**) and successfully programmed a '2550 with <I think> WINPIC800, IIRC, before discovering I didn't have any suitable substitute transistors/inductor to build a PK2 clone board.

I ordered a genuine PK2 and binned the idea...

 

[avi]

Yes, I've tried to switch the D+ &D- ineffectually!

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Have you checked the D+ and D- lines, as Sarma suggested?

One less problem to rule out.

 

[avi]

Things I've tried so far...

1) Reprogram the PIC18F2550 (by ART2003).- programmed successfully!
2) when I press on SW1 and then plug-in the usb, the "busy" LED blinks.- means the Crystal is working...
3) I've tried to switch the D+ & D-
4) I've tried to connect the PK2 in 3 defferent PC\laptops, in none the
PICkit 2(v2.55) application has detected the circuit.

TNKS for your help

 

[3v0]

As suggested earlier it is time to post the schematic and photos of your circuit if you can.

What version of windows have you tried. If XP does it make the right sound when you insert and remove the USB ?

Do you have the right value for the cap on pin 14, VUSB. If polorized is it backwards?

 

[mvs sarma]

That's the thread.

whether the OP is talking about this schematic and the associated board?

 

[avi]

Yep, this is the circuit I've built.

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[3v0]

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What about the other questions.
Have you checked the VUSB cap?
Which version of windows are you using?


This is not a difficult thing.

4) I've tried to connect the PK2 in 3 defferent PC\laptops, in none the
PICkit 2(v2.55) application has detected the circuit.

That is like saying my car does not work. Are the tires flat or is the motor missing? Does the PC detect the USB device? Does it tell you it does not know what the USB device is (unknow device) or does the PC not even know the device is there.

 

[mvs sarma]

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you have wasted time so far. you could have put it on the first day along with the post,
BTW,
Check the value and polarity of C5(100uF).
Also check whether you used 100 ohms for R12 and R13.
Already 3v0 pointed towards capacitor (0.47uF) on pin14.
these transistors have EBC order if you have used 2N3904 and 2N3906. check for proper mounting. and polarity of D1 and D2. They are Schottky not Zenor.

Do you have a DMM by chance?
if so you can measure some points and tell the voltages, w.r.t., pins 6 and 19 being ground.
1. pin 20 $.75 to 5V expected.
2.cathode of LED1 (green)
3. on +ve terminal of capacitor C1.(check for proper mounting. you may expect 13,3 V approx.
(whether this would come during Vpp test thro' software, and during programming or reading times only?)
Check whether 20MHz crystal has been in place -- already pointed by Bill!

 

[mvs sarma]

Thanks to Mickster, the ART2003 programmer is an LVP type and the RB5(pin26 is connected to Mclr)

Here is an extract of what Fox delta Site said

"FD-ART2003
Developed specifically for programming of PIC 18F2550 micro controllers, this parallel port, no-power, programmer is the smallest of all programmers ever built.

A DB25 Male Connector, one capacitor and a resistor makes this Port Powered programmer.

Programmer takes its power from Parallel Port pins 2-9. VPP for this programmer is 5V and hence "LVP" must be selected in programming software. (See art2003 screen shot Document given below)"

Once pin 26 is used for LVP programming a, perhaps it cant be used as an Input pin with a switch SW1.
Perhaps this is what AVI (the OP) has purchased the issue.

Now, AVI has to find a way to program the device, after proper erasure, with a standard Programmer with Vpp at 13,xx V.
Perhaps the whole thing settles.

 

[skyhawk]

Although I would like to be proven wrong, I believe the problem lies with the fact that the download button is on the PGM pin. When the chip is programmed with LVP, if the PGM pin is high the clock is stopped and the 18F2550 is in the state to be programmed itself. If PGM is low then the 18F2550 goes into and stays in the bootloader. When the 18F2550 is programmed using HVP, the PGM pin functions as a normal I/O pin and things are fine.

I would recommend setting up a minimal circuit on a breadboard and determining whether the chip will enumerate in that circuit. If it wouldn't then nothing else matters.

 

[mvs sarma]

Although I would like to be proven wrong, I believe the problem lies with the fact that the download button is on the PGM pin. When the chip is programmed with LVP, if the PGM pin is high the clock is stopped and the 18F2550 is in the state to be programmed itself. If PGM is low then the 18F2550 goes into and stays in the bootloader. When the 18F2550 is programmed using HVP, the PGM pin functions as a normal I/O pin and things are fine.

I would recommend setting up a minimal circuit on a breadboard and determining whether the chip will enumerate in that circuit. If it wouldn't then nothing else matters.

You appear correct.
keeping RB5 high and if and if you use HVP style, it is fine
The ART2003 doesn't have the high voltage. Both Mclr and RB5 are looped and connected to Vdd. Thus it is sure that no HV will ever come.
do you mean that with RB5 kept high and LVP programmed is good as HVP programming?
if so why on earth , the trouble of generating Vpp for flash programmersfor those chips that have LVP facility.

 

[skyhawk]

do you mean that with RB5 kept high and LVP programmed is good as HVP programming?
if so why on earth , the trouble of generating Vpp for flash programmersfor those chips that have LVP facility.

No. For the chip to run if programmed with LVP PGM must be pulled low. Pulling PGM high stops the clock and PGD and PGC become programming pins.

You use HVP programming rather than LVP to avoid losing PGM as an I/O pin.

 

[3v0]

Skyhawk and Bill are correct With the chip in the LVP configuration you only have a choice between loading an OS or re flashing the chip via LVP.

An experienced programmer could get around that with what SHOULD be a small change to the boot loader code.

Move the BLOAD switch to an unused pin: RB0 or RB1 should work. Tie the PGM pin to GND. Then use the bodged but working unit to program another 18F2550 with HVP. Install the new chip and move the switch back to RB5.

EDIT: Check original PK2 schematics to ensure the pin you use is actualy unused by the software!

and


AVI said the 18F2550 flashes the red light if he holds the boot button down as he inserts the USB. This indicates that the uC is running the bootloader and waiting for a OS download. I tryed keeping BLOAD pressed and XP sees the USB device and you can program it from the PICkit2 tool. Doing so will not result in a working programmer but it will tell you the USB is OK.

 

[skyhawk]

When I press SW1 (RB5 pull down) and plug-in the usb, then the Windows detects some un-recognized usb connection, and the "busy" LED blinks for a few sec.

I'm not sure about what you mean by:

Windows detects some un-recognized usb connection

When I conduct the experiment with one of my programmers, I get a two-tone audio signal and nothing else. What do you get?

 

[3v0]

I get the same as you. Who are you quoting ?

 

[skyhawk]

Who are you quoting ?

I am quoting Avi.

 

[mvs sarma]

Skyhawk and Bill are correct With the chip in the LVP configuration you only have a choice between loading an OS or re flashing the chip via LVP.

An experienced programmer could get around that with what SHOULD be a small change to the boot loader code.

Move the BLOAD switch to an unused pin: RB0 or RB1 should work. Tie the PGM pin to GND. Then use the bodged but working unit to program another 18F2550 with HVP. Install the new chip and move the switch back to RB5.
EDIT: Check original PK2 schematics to ensure the pin you use is actualy unused by the software!
and
AVI said the 18F2550 flashes the red light if he holds the boot button down as he inserts the USB. This indicates that the uC is running the bootloader and waiting for a OS download. I tryed keeping BLOAD pressed and XP sees the USB device and you can program it from the PICkit2 tool. Doing so will not result in a working programmer but it will tell you the USB is OK.

To be able to reprogram using another pin, you mean changes in asm code to redefine BLOAD pin.
for that one needs the source code.
and If the source is in C18 , perhaps many hobbyists or new entrants would not be able to do it , so easily, I fear.

 

[3v0]

IIRC microchip has the bootloader code online somewhere. I was thinking that it might be somthing we could do for the people who need it. LVP's are the easiest to build and it may be a reasonable way to solve the chicken and the egg problem of not having a programer to build a programmer.

I could be wrong but it could be as simple a changing one or two lines of code.

3v0

To be able to reprogram using another pin, you mean changes in asm code to redefine BLOAD pin.
for that one needs the source code.
and If the source is in C18 , perhaps many hobbyists or new entrants would not be able to do it , so easily, I fear.

 

[avi]

Some Answers

1) C4 (470nF)- checked OK.
2) I'm using Windows XP-SP2.
3) the only component I'm not sure about is D1(BAT41), I'm usign an "unknown" diode (clear, transparent, body with nothing printed on it, I have measured Vd=0.24v).
4) Cystal connection is checked- OK!!
4) measured voltages:
Voltage supply from usb= 5v - OK
V (c4)= 0V !!!
V (C1)= 4.7v (=5v-Vd...)

I think I gonna replace the PIC18F2550 with a new one.

by the way, somebody has written here that the PIC18F2550 has kind of internal program. I didn't understand- can I use this program without reprogrm it using the ATR2003?


TNX for all, regards,
Avi.

 

[mvs sarma]

1) C4 (470nF)- checked OK.
2) I'm using Windows XP-SP2.
3) the only component I'm not sure about is D1(BAT41), I'm usign an "unknown" diode (clear, transparent, body with nothing printed on it, I have measured Vd=0.24v).
4) Cystal connection is checked- OK!!
4) measured voltages:
Voltage supply from usb= 5v - OK
V (c4)= 0V !!!
V (C1)= 4.7v (=5v-Vd...)
I think I gonna replace the PIC18F2550 with a new one.
by the way, somebody has written here that the PIC18F2550 has kind of internal program. I didn't understand- can I use this program without reprogrm it using the ATR2003?
TNX for all, regards,
Avi.

Please confirm whether the Crystal is 20MHz?
You can change D1 with 1N5817 perhaps.

Can you get access to another programmer which can use 13V programming and that can accommodate 18F2550 instead of ART2003? Perhaps another PICKIT2 with any person or institution that could help you out locally.

If so you can take the PK2.5xx file there and get it programmed and put back in your programmer. While doing this, the chip needs a full erase and the program.