Olimex Support Forum

Microcontrollers => ESP32 => Topic started by: GeorgeFlorian on February 28, 2024, 09:57:11 AM

Title: Pins on ESP32-POE-ISO ?
Post by: GeorgeFlorian on February 28, 2024, 09:57:11 AM
I am looking for a POE board that has 2 ADC input pins, 3 digital input pins and 2 digital output pins.

I was looking at: ESP32-POE-ISO (the basic one), but I can't figure out if it has enough pins and the ones that I need.

Here is what I've mapped out:
- for input GPI 33, 35 and 36
- for ADC GPIO 13 and 14
- for output GPIO 15 and 16

I don't understand how EMAC pins are considered good to use if they are connected to the ETHERNET Port.

This is the joystick: https://ibb.co/fp21SJV

Also, should I add level converters between the joystick and the ADC input pins ?

Thank you.
Title: Re: Pins on ESP32-POE-ISO ?
Post by: LubOlimex on February 28, 2024, 11:02:36 AM
We only have two ESP32 boards with integrated PoE powering but you can turn any ESP32 board to PoE-board if you use external splitter like MOD-POE-V2:

https://www.olimex.com/Products/Modules/Ethernet/MOD-POE-V2/

ESP32 chip has 2 ADCs but the second ADC can only be used if you don't use the WIFI at the same time:

https://docs.espressif.com/projects/esp-idf/en/v4.2/esp32/api-reference/peripherals/adc.html
Title: Re: Pins on ESP32-POE-ISO ?
Post by: GeorgeFlorian on February 28, 2024, 11:33:14 AM
I've never worked with ADC pins so I don't understand why there are multiple ADC pins listed in the GPIO Map (https://www.olimex.com/Products/IoT/ESP32/ESP32-POE-ISO/resources/ESP32-POE-ISO-GPIO.png) but you said that the ESP has 2 ADCs.

I can see that there are ADC 1 and 2 with multiple channels.
Title: Re: Pins on ESP32-POE-ISO ?
Post by: LubOlimex on February 28, 2024, 11:42:13 AM
ESP32 modules are very popular, if you are new to ADC just search online for the following string "ESP32 ADC tutorial", there are literally hundreds of good guides with instructions (and also the official espresiff site with full details about ADC).
Title: Re: Pins on ESP32-POE-ISO ?
Post by: GeorgeFlorian on February 29, 2024, 12:30:13 PM
Quote from: LubOlimex on February 28, 2024, 11:42:13 AMESP32 modules are very popular, if you are new to ADC just search online for the following string "ESP32 ADC tutorial", there are literally hundreds of good guides with instructions (and also the official espresiff site with full details about ADC).

Thank you. I've found lots of tutorials.

All I need is a valid pin list, because many of them are designed as EMAC (ethernet) and I don't know if they can be used.

Can I use the following pin map:
- for input GPIO 32, 33, and GPI 35;
- for ADC GPIO 36 (ADC1) and 13 (ADC2)
- for output GPIO 15 and 16;
Title: Re: Pins on ESP32-POE-ISO ?
Post by: GeorgeFlorian on March 04, 2024, 11:21:46 AM
Quote from: LubOlimex on February 28, 2024, 11:02:36 AMWe only have two ESP32 boards with integrated PoE powering but you can turn any ESP32 board to PoE-board if you use external splitter like MOD-POE-V2:

https://www.olimex.com/Products/Modules/Ethernet/MOD-POE-V2/

ESP32 chip has 2 ADCs but the second ADC can only be used if you don't use the WIFI at the same time:

https://docs.espressif.com/projects/esp-idf/en/v4.2/esp32/api-reference/peripherals/adc.html

I only need a small POE-powered ESP32 board without using external splitters.

Please confirm that the EMAC labeled pins, like GPIO16, can be used at the same time as the ETHERNET port.

I want to use the following pins at the same time as the ETHERNET:
- for input GPIO 32, 33, and GPI 35;
- for ADC GPIO 36 (ADC1) and 13 (ADC2)
- for output GPIO 15 and 16;

I won't use Wi-Fi, SD Card or UEXT Connector.
Title: Re: Pins on ESP32-POE-ISO ?
Post by: LubOlimex on March 19, 2024, 08:44:43 AM
GPIO32 is absolutely free can be used without issues.

GPIO33 is absolutely free if you use board with WROOM module (aka not WROVER, aka without PSRAM).

GPI35 is absolutely free can be used without issues.

GPI36 should not be used for ADC since it has Schottky diode (this has not linear characteristic), it also has 10k pull up resistor which shouldn't be a problem (analyze around UEXT on the schematic).

Same for GPIO13 again is free but it has 2.2k pull resistor that should be considered. Still GPIO13 can be used for ADC.

It is fine to use GPIO15 and GPIO16 for output GPIO.

Notice that if you use two ADCs, the WIFI won't work.