'KROT2-XM' (mole), new project Xmega32

[Wiltran]

Bridge mode connection

Forgot to mention, use another output in “bridge” mode to increase TX current for low Q coil.

I dont understand. If you connect coil to TX3 and ground you are switching R3 and C1 out of the circuit. how would this resonate at 8500Hz?

[Tepco]

Not connected to GND, but between TX 1 and 3, (pins 5&8 34119), keeping resonant capacitor in circuit. Output is “bridge” type, two outputs in anti-phase, this will double voltage available to drive coil resonant circuit. My coil is bad too, some 20cm improvisation with too low inductance (tuned to around 11.5kHz with 220nF capacitor, but wire is too thin, high resistance, not shielded etc) I have to build proper original coil first,to make any meaningful test.

[Wiltran]

Thanks Tepco!

[WM6]

No problem at all with coil auto-tuning. It just monitor TX current consumption, searching for maximum, if it miss 1 or 3%, no big deal. Especially with alu wire coil and lower Q, or higher resistance MD3030 coil, you can always tune it manually.

Ther was funny stuff with MD3030 coil. Ideal balanced to say 7mV it cannot detect nothing not even in touch. But out of balance at say 700mV it can detect silver coin at more than 25 cm.

[WM6]

XMEGA32 chip on Geo's board is now programmed.
Board is now in life but I cannot go trough setup procedure, because I realized that my 5V 1602A LCD modules are not adequate to work with KROT-2. We need 3.3V 1602A module (with 3.3V logic inclusive). So back to eBay again.

For programming I used Zeptoprog II USB programmer:

http://www.mattairtech.com/index.php/development-boards/zeptoprog-ii.html

and AVRDUDE program (under Ubuntu) for programing AVR MCU inside Terminal interface.

I used this AVRDUDE command code in Terminal for flashing XMEGA32 chip:

avrdude -p x32a4 -F -c avrisp2 -P usb -U flash:w:KPOT_V06A.hex

In procedure Zeptoprog II USB programmer need to be connected first to USB and set to programing mode. 5V Vtgt jumper should be disconnected to not damage 3.3V MCU.

Then we associate "PROG" connector pins on XMEGA board with adequate pins (GND; Vtgt; PCK/RTS/RST; data) on Zeptoprog II USB programmer.

If all is OK, issuing above command in Terminal and XMEGA programming will be carried out.

After successful procedure Terminal display should look like this.

[Geo]

XMEGA32 chip on Geo's board is now programmed.
Board is now in life but I cannot go trough setup procedure, because I realized that my 5V 1602A LCD modules are not adequate to work with KROT-2. We need 3.3V 1602A module (with 3.3V logic inclusive). So back to eBay again.

For programming I used Zeptoprog II USB programmer:

http://www.mattairtech.com/index.php/development-boards/zeptoprog-ii.html

and AVRDUDE program (under Ubuntu) for programing AVR MCU inside Terminal interface.

I used this AVRDUDE command code in Terminal for flashing XMEGA32 chip:

avrdude -p x32a4 -F -c avrisp2 -P usb -U flash:w:KPOT_V06A.hex

In procedure Zeptoprog II USB programmer need to be connected first to USB and set to programing mode. 5V Vtgt jumper should be disconnected to not damage 3.3V MCU.

Then we associate "PROG" connector pins on XMEGA board with adequate pins (GND; Vtgt; PCK/RTS/RST; data) on Zeptoprog II USB programmer.

If all is OK, issuing above command in Terminal and XMEGA programming will be carried out.

After successful procedure Terminal display should look like this.

Hi WM6. If we must wait again for ebay ... they are bad news, but what other to do
Smity at post #25 wrote """It is applied normal display 1602 (+5 volts). Specifically to buy a 3.3 volt is not necessary. Components C26, 27, D1, 2, R19, 27 form a negative voltage and allows you to control the contrast of the "menu" of the instrument. Backlight unit, is also included in the "menu"."""".
Did you play with contrast????

Regards

[WM6]

Hi WM6. If we must wait again for ebay ... they are bad news, but what other to do
Smity at post #25 wrote """It is applied normal display 1602 (+5 volts). Specifically to buy a 3.3 volt is not necessary. Components C26, 27, D1, 2, R19, 27 form a negative voltage and allows you to control the contrast of the "menu" of the instrument. Backlight unit, is also included in the "menu"."""".
Did you play with contrast????

Regards

Hi Geo

Contrast is working if I supply VDD pin of LCD module with 5V only. Present solution with 3.3V LCD VDD pin supply do not imply to contrast by changing R19 value or barely remarkable. In no case I can get visible character on display, so I conclude that there is logic level 3.3V that is not sufficient to manage LCD module logic part. I did not check other parts in line with R19 you mentioned (PCB leads are very thin and sensitive to de-soldering parts for testing).

Geo, if you are willing to continue play with it, I can send this board you today - please PM me your shipping address.

[Wiltran]

WM6, I tried several 5V displays, and they all work good so that is not your problem. As you power it up, you should hear a series of tones. yes, if your contrast is set too low , you wont see anything displayed on the screen.

[Wiltran]

Hi Tepco, I tried connecting TX coil in bridge mode. I am using Dip version of board. The connect points are TX1.1 and TX1 on the board. I added a 5 ohm resistor at TX 1.1. There is no current output to coil. have you tried this bridge mode?

[Geo]

Hi Geo

Contrast is working if I supply VDD pin of LCD module with 5V only. Present solution with 3.3V LCD VDD pin supply do not imply to contrast by changing R19 value or barely remarkable. In no case I can get visible character on display, so I conclude that there is logic level 3.3V that is not sufficient to manage LCD module logic part. I did not check other parts in line with R19 you mentioned (PCB leads are very thin and sensitive to de-soldering parts for testing).

Geo, if you are willing to continue play with it, I can send this board you today - please PM me your shipping address.

Yes....

[WM6]

WM6, I tried several 5V displays, and they all work good so that is not your problem. As you power it up, you should hear a series of tones. yes, if your contrast is set too low , you wont see anything displayed on the screen.

Series of tones at power up are the same as on author (Andrey) board, so no problem with start tones. Changing R19 do not imply to contrast (or barely visible) - except if I change VDD supply on LCD (separate) to 5V - in this case contrast works OK. But there are not info/character generated on display no matter of contrast and no matter of VDD
supply.

Maybe I need to change some (soldered) jumper on LCD module, but I didn't find technical data of this jumpers for my LCD modules type JXD1602A.

Can you post photo of your DIP version of KROT-2?

[Wiltran]

[WM6]

Good work Wiltran.

As I can see you didn't always use exact value of components as per author suggestion (par example R1 and R2)?

[Wiltran]

In the original Schematic it shows r2 and r1 as 1 ohm, but in the parts list that came with the DIP version it shows R2 with a 2ohm. Also the newest schematic show 1000 mfd electrolytic replacements. I am also going to replace my 2200pf capacitors with COG(NPO), hopefully for better stability. I am using unshielded DD coils, which are not yet nulled, so I am sure that will help.

[WM6]

Also the newest schematic show 1000 mfd electrolytic replacements.

Hi Wiltran, where did you find newest KROT-2 schematic? I am checking http://radiodom.ucoz.ru/index/selekt...t2_m_quot/0-17 site, but there is still old known schematic?


Also, what sort of C did you use in TX tank circuit?
Author suggest metalized polystyrene film capacitors (I used available polyester) and to solder it direct to cable connector.