I'm trying to program an Arduino Pro Mini 3.3v
I am using a Deek-Robot FTDI 232 chip.
Now I didn't try to use it yet, because the VCC output of the programmer reads 5V even though it is set to 3.3v.
I find that quite weird; is it normal? Or it will burn my board if I try it?
Yes, you will damage the Pro Mini if it is running at 3.3V, and the I/O pins are exposed to 5V.
The Pololu AVR programmer is vastly more flexible and easier to use than any other on the market. It can do both ISP and serial bootloader programming, and acts as a separate USB to serial com port adapter as well.
Which output?
There is a 5V pin that always reads 5V. It the TX and RX that switch between 3.3V and 5V. Have you tested the TX level?
It's this pin:
It's 5V. I can't test the Tx pin, I think I would need an oscilloscope for it.
I guess I can lower it to 3.3V with a voltage divider if needed, it would just be weird...
That pin will always read 5V.
You do not need to power the board by the programmer. For 3.3V you just need TX, RX, and GND. Power the board by a 3.3V source. You need to remember to reverse the TX and RX between the programmer and the board. I use the same chip on a similarly inexpensive board for programming my ESP devices and they are 3.3V.
Great, I will give it a shot. Thank you for the quick response.
No, just use your voltmeter. The idle state of TX is HIGH.
I don't think that's right. To program an Arduino, you have to reset it, and that takes an extra pin apart from TX and RX; it's the DTR pin in the picture. It's done by the USB interface chip on most Arduinos, but the Pro Mini doesn't have that, so it needs to be done externally. Voltage is a separate thing to worry about.
You just have to hit the reset button when the programmer tries to kick in.
FWIW I have one almost exactly like this on on eBay.
That same (your "5V" pin) is marked Vcc and changes from 5V to 3.3V with their jumper.
I can't even imagine why Deek-Robot would create such a design.
Thank you for your replies. I think I'll drop the voltage to 3.3V and try it. I'll update how it works once I try it.
Nice little homebrew.
You should select your last reply as the solution, so people won't make more suggestions.
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