ESP32 Forum

Good day to you all. I have a few pretty basic questions.

I am wanting to replace an Arduino Mega with an ESP32-S3 so that I can set the ESP up as a simple server to interact with browsers on my LAN and so that I can make program changes via OTA and so that I can try out the S3. I am not sure which of the ESP32-S3-DevKitC-1 dev boards to get.

I will need 22 GPIO set up as digital outputs, 3 GPIO set up as digital inputs and at least one (and hopefully two if I can get two to work) GPIO set up as a one wire interface to read temperatures from a number of DS18B20 sensors.

It looks like most of them should work so I have (so far) chosen ESP32-S3-DevKitC-1-N8R8 because it seems that Mouser keeps plenty of those on hand.

Will that board be OK for my application? Is there a better choice?

Thanks,
JP.

That should work just fine. In theory it's a bit overkill (as you probably don't need as much as 8 MiB of flash and could do without the 8 MiB of RAM entirely), but those things tend to not get 'in the way', so it's fine.

How accurate is the on board real time clock under fully powered conditions? I will not be using any sleep or low power modes.

I haven't been able to search out a definitive answer on this.

Thanks.

Without sleep, the RTC uses the 40MHz crystal as a reference and as such should be as accurate as that. The RTC must be <=10ppm precise for WiFi to work, so that means you can expect a deviation of less than a second a day. If the thing is connected to the Internet (or a local network with an NTP server available) it's trivial to sync the internal clock up to the actual time, btw.

Sounds good.

Most of the time the controller will be able to contact an NTP server, but there may be stretches of a few days where it can't.

So if I use GPIO 0 to 18, 21, 35 to 38, 45, 47, and 48 as simple digital I/O I should be ok, right?

Thanks,
JP.

For those pins, only GPIO0 is a bit tricky as it's a bootstrap pin. The devboard will have a pullup and a button to ground connected to it, so that may affect the signal level, and the state of that pin on startup will determine how the chip boots. If you're okay with that, you can use it as an IO.

OK, I'll leave GPIO0 til the end and only (try) to use if I have to.

Thanks,
JP.