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Topic: Manual RST signal during upload (Read 504 times) previous topic - next topic

noob314

Instead version of RS232 board with RST and CTS (MAX3232, 3.3-5V), they sent me this without, which cannot be of any use with Pro Mini:

https://www.ebay.com/itm/RS232-To-TTL-Converter-Module-Serial-Module-DB9-Connector-3-3V-5-5V-Arduino-nC-B-/372729291563

While it is in process of returning the whole stock, I'm thinking of possible that perhaps manually can be sent signal in some crucial moment and successfully upload the firmware ( 5V -> 10K resistor -> RST pin). That theoretically may be possible, if only one signal is necessary before sending firmware by avrdude in exact moment. Or perhaps is still necessary multiple well timing signals, in which case that is not possible to do manually.

Anione is aware of exact procedure regarding RST pin during upload?

DrAzzy

Um, how are you planning to use that?

That's not a serial adapter, it's just a converter between RS232 voltage levels and TTL voltage levels... Like, I'm not sure what you're hoping to do with that, but I have a bad feeling that it doesn't do what you think it does.

In any event, yes a manual reset at the right moment will do the trick. You need to release reset right as it shows the sketch size.
ATTinyCore for x4/x5/x61/x7/x8/x41/1634/828/x313 megaTinyCore for the megaavr ATtinies - Board Manager:
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noob314

#2
Dec 08, 2019, 10:43 am Last Edit: Dec 08, 2019, 12:49 pm by noob314
MAX 3232 board (instead MAX232, to support both voltage levels) is all I need for ProMini with boot loader already in, however board have to have RST and CTS pins as well. I have no need for an adapter. I have even homemade my own MAX 3232 board with TH components and all worked fine, however I have  needed spare SMD boards stock.

Anyway, thank you very much for exact info regarding manual procedure with RST signal. With no need for complex signals here, that is quite handy to know and I will certainly test that.

DrAzzy

aaaah, i see, so you have an rs232-level serial adapter already.

yeah, DTR goes low when the port is opened, a 0.1uF cap on the pro mini (and most other avrs that don't have native USB) is connected between DTR and reset. That combined with the 10k pullup on reset forms an RC that converts the high to low transition into a low pulse to reset the chip when the port is opened, so the bootloader, which runs immediately after a reset, can receive a sketch.
ATTinyCore for x4/x5/x61/x7/x8/x41/1634/828/x313 megaTinyCore for the megaavr ATtinies - Board Manager:
http://drazzy.com/package_drazzy.com_index.json
ATtiny breakouts, mosfets, awesome prototyping board in my store http://tindie.com/stores/DrAzzy

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