TL866II Plus not pulling RST low enough on a miniPro clone.....

[hazzer]

Beginners question on the TL866II Plus ( Firmware V04.02.128 ) and Xgpro V11.90.

Im trying to programme a 5V 16Mhz Arduino ProMini (Clone) over ISCP using a TL866II Plus.

It fails to programme or even read the chip ID, looks like the RST line isn't pulled low enough by the TL866,
and looking at the clone MiniPro board I can see a 1K pull up resistor on RST.

If I removing this 1K resistor then it all works and I can then programme and read the ProMini 328P contents as expected.....

but I would have thought the TL866 would be able to pull a low voltage on the RST line through a 1K resistor?

attached is a screen grab of the RST line with the 1K resistor in circuit, the RST is pulled down to 1.4V ( from 3.6V ... )
and the VCC supplied by the TL866 is 4.5V.

Question... is this what you would expect - or might there be a problem with the TL866???

Thanks

Harry

[m k]

Yes - No.

2mA/pin is pretty much.

[Mechatrommer]

have you bought this? https://www.aliexpress.com/item/33047996482.html

One of the main issues is the poor signal quality because many circuits fail to be designed for the in-circuit-programming originally...
There is a signal driver chip that can make in-circuit-programming signal stronger and make programming more reliable...

either that, or increase the pull up resistor value to the recommended value for the in-circuit-programming originally (4.7-10kOhm), i normally used 10kOhm to save the world's energy consumption... TL866II+ is a trap for young players, i have to buy many adapters that cost nearly as the programmer itself because i want to program some flash chip, and to ensure i can program many others... ymmv.
https://onlinedocs.microchip.com/pr/GUID-F626284A-58F0-4C25-A6F3-0EA5054F3E2B-en-US-6/index.html?GUID-B80B25FF-E9D7-4766-B562-DA197B8B938C

[Peabody]

The schematic I have for the Pro Mini has a 10K resistor on the reset pin, and a 0.1uF capacitor in series to the DTR pin.

[hazzer]

Thanks for the links, yes the TL866 adaptor looks useful, later I want to look at DebugWIRE so moving the clone miniPro board to a 10k resistor is prob what I will do.

I did ask on the webpage https://xgecu.myshopify.com/collections/tl866ii-plus-programmer
and was told ...
" XGecu
You can adjust the VCC CURRENT IMAX to 350MA, if it still doesn't work, you need to disable the ICSP VCC ENABLE, then the target board power supply".

but on my software the current is locked to default (120ma) and greyed out, I think this is pretty standard,

unless someone knows how to unlock the current setting?  but that's for another post...

thanks again - 10K it is....

Harry

[hazzer]

Just to close, replacing the 1K RST pull up resistor with a 10K resistor on the (cloned) MiniPro board has fixed all the issues.

Thanks for all the suggestions and links.

73

Harry