replacing the crystal with a TCXO

You could roll your own Duinos,

This shows using the ATmega328P (Uno/Nano/Mini boards have one) and the ATmega1284P (32 IO pins, 16K RAM, 2 Serial) but the same lesson applies to like over 20 other AVR chips there are core files for.

How far away from Venice is Arduino HQ? I feel a bit jealous.

You could roll your own Duinos,

You could, but it's not a very profitable exercise.

Basically any board with either crystal or ceramic resonator can be adapted by removing the original and any associated loading capacitors (which are usually incorporated into the ceramic resonator version) and possibly reprogramming the chip to the appropriate clock option. The only difficult part is actually removing the original resonator and connecting to the pads. :roll_eyes:

GoForSmoke and Paul__B, you didn’t address the issue of the voltage, 5 vs 3.3 V and I don’t understand if I can get a reliable Arduino PCB somewhere which would accept the 3.5 x 2.5 TCXO with the proper pinout. Paul__B when you say that removing the original and connecting the pads is difficult what do you mean? too difficult for somebody who has never done it? I was thinking of destroying the original on a milling machine and then soldering the new one with a small 10 W iron. p.-

OK, the 3.3 V is a point as it may not reliably clock a 5 V Arduino. There is not going to be a standard Arduino (or clone) to match your TXCO pinout, nor is there one that will provide level translation or the alternate 3.3 V connection (plus the required adjacent decoupling capacitor). You are looking at making an adapter board to mount the TXCO and a level translator such as a 74HCT14 with the decoupling capacitors - but that is in itself perfectly straightforward.

You should use a hot air rework tool to remove the original resonator.

Making your own is not about profit so don't use that as a business plan unless it's that building a prototype part.

You make your own when you want to get what you want, including the learning part you don't get when you buy appliances. If you make your own 328P standalone that runs on 3.3V you learn right away that it can run okay at up to 10MHz, maybe 12 with less margin but most people run at 8MHz or less with more margin.

There are many 3.3V Arduino compatible boards though most run ARM chips, not AVR.

When you make your own just to see, you have the 3.3V choice but not at 16MHz. Is there no 5V version of TCX0?

for some reason I cant find low cost 5v tcxos, I could run at 10 MHz, I dont understand any more what the simplest choice would be. It would fine to have a pcb printed, or better already printed since I dont need any special feature, plenty of tcxo of the right format 3.5 x 2.5 mm, only at 3.3 v

You can get breakout boards for a lot of surface mount devices and wire them together just to get the circuit right before making a PCB or you can see how many PCB designs it takes before you get the bugs out.

How much cheaper is a TCX0 than a crystal and caps that it is worth running at half speed?

I understand they are under my name but how do I locate my name in the first place without locating a post?

Make a post and when you see it there in the thread, there you are.
You can do that down in the Bar Sport Topic and have some fun while you're at it.

Goforsmoke what you are saying is that I could get a breakout board, install my 3.3 v TCXO with a level translator on the board, disconnect the original crystal and connect a wire from the breakout board to the arduino board and I am set?

I have serious doubts that the clock source can be voltage leveled and still BE a clock source.

ARM chips run at 3.3V but the slowest I know of run at 48MHz.

But hey! An AVR at 3.3V with a rock-steady clock (resonators can be off minutes per day) isn't a bad thing. They use less power especially if you don't include a USB chip and some other bits found on Uno and Nano boards.

If you are only hobbying it is cheap to build using DIP chips on protoboard, not sure what route you take with surface mount but I've seen boards for some of those at DIPMicro and around. I have seen boards to give DIP-format pins to surface mount chips.

The DIP ATmega328P-PU cost just over $2 for 1 last I saw on Mouser.I call that cheap.

Looking for breakout for your TCX0, which one you have makes a difference. I can't tell which links to show.

Considering what these modules are for, I don't expect cheap and I do expect them to be used with automotive AVRs in hot environments. This is as deep in the topic as I care to get.