Dual Core Programming for the Raspberry Pi Pico, ESP32, and ESP32-S3 Using the Arduino IDE 

I use the two cores of ESP32 for robotics, one for communication with the host and another for closed loop control. This way I get a very low latency in the control loop and I still can change the target position and sample current positions at relatively high frequencies.

Good timing! I'm starting a project for a digital audio synthesizer, and I'm planning to use dual cores, and a little later, RTOS, so very useful!

I remember back then Lord Gary mostly explain Android, now he explain every technology! Respect for this guy :)

Thanks Gary. watched this videos 4 times for sharp understanding. and read all the below comments. now I'm handson. cheers😁

Reads will correct themselves and will not inherently corrupt the data; however, if multiple reads are required (e.g. long on 8b processor or double on 32b), then you might read some bytes before the value changed and the rest after the value changed. In this case this particular value is corrupt. If you don't lock your reads, be careful how you use the result. This corrupt value might otherwise cause the code to branch incorrectly or to perform incorrect calculations and/or to store incorrect values.

This info will be very useful. Thank you.

Outstanding explanation! Thanks

Great video as always Love the theme Thanks for sharing your expirence with all of us 👍 😀

Very nice reference to Gibson.

Coming from MicroPython on the Pi Pico this is so simple to implement it hurts, thank you for the video.

Круто! Спасибо Gary!

Looking forward for ypur explanations of mutex, semaphores and synchronizations. Thanks in advance

I want to separate communication i2c out to core 0 the technique you showed is a nice start. Thanks

Just to clarify to anyone interested in parallel programing (since I didn't know this when I bought the esp32) the esp32 can run more than 2 tasks at once thanks to freeRTOS(I don't know about the pico) that is why the code for the esp32 is a bit more complicated,some people say they got around 50 tasks running without any problems Ps core 0 is responsible for wifi and Bluetooth so if you are using those don't overload it with complex tasks

Great vid with a cool explanation that can, as you said, be a template for other codings (simple or complex). Please keep the technical threads coming on multi-thread processing with all their nuances and your videos on other programming languages.

Very helpful. 😀

Really good content. Post more of these videos.👍

*GARY!!!* Good afternoon Professor! Good afternoon fellow classmates! Stay safe out there everyone!

Sehr gut

Thanks! This is very helpful for our needs as we work on support for the impressive RP2040.

¹1¹st; I've been in computers over a half century, and I find Gary's presentations particularly relevant with extraordinary clarity.

Reads can absolutely become corrupted if you're reading a multi-word structure. Unless you're absolutely sure your read operation is atomic you should definitely lock the mutex on reading. Also for the locking/unlocking problem with mutexes, and easy way to solve the problem is to create a MutexLocker class that takes a mutex reference and locks it in the constructor, and unlocks it in the destructor. That way you can be guarenteed that any way you exit out of a function (even if an exception is thrown up the stack) the mutex when be unlocked when the MutexLocker goes out of scope.

Always interesting and informative! Please do a video on semaphores etc. can’t wait 👍

How does dual core work with serial communications? Do you do the lock/unlock on a variable, and then use that to determine which core gets to use the serial port, or is there a better way?

cool. is there a python example of accessing both cores

Thanks for the splendid video. Very informative. I guess the same programming will work on an Arduino RP2040 connect, right?

Are any objects inherently thread-safe in this arduino/pico "land"? In some other languages you have objects e.g. queues that are thread-safe amongst others. Meaning that the standard library handle the locking for you. Would be nice to get an overview of that. I'm glad however that you touched upon this because two threads working seperatly without communicating with each other is rearly usefull in my experience.

This was *exactly* the video I needed, but unfortunately I'm missing something. I just installed the latest IDE (2.2.1) with the current MBED RP2040 board manager package (4.0.8). The locking example does not compile for me. It seems to not find semphr.h, nor freeRTOS.h, even if I install the freeRTOS library through library manager. Thoughts? I need to have one sensor reading data on core 0, and another reading its data (asyncrhonously) on core 1. The data on core1 needs to periodically get shared back to core0 via a global float, so the "current" values of both sensors can be output synchronously via serial. Any advice appreciated.

How does this change if using the ST Microcontrollers? For example, if the peripheral assigned to each core.. can they be changed at run-time? For example, can the cores communicate, such that one passes UART access to the other? Would love to see an overview example on how the memory works in dual-core applications. For example the STM32H745 has 2MB of flash, and 1MB of RAM, but how can you allocate most of it to the M7, and the remaining to the M4? Is it possible to debug both simultaneously thru a single JTAG/SWD connector? How does communication work between cores?

What core do interupts run on?

How do you add the raspberry pi pico to the arduino IDE? Is it through the board manger?

This is a very interested and useful video. Do you know how I can use the Arduino IDE to change the clock speed on the Raspberry Pico? I know it is possible to overclock it by quite a bit, but I have not been able to figure out how to do it.

Great video, but unfortunately I cannot get the code to give output from the second core on my actual Pico board, I only get output from loop0. I haven't got a Seed board to try. I am using Arduino IDE 2.0.4 and ArduinoMbed OS RP2040 v4.02 is installed. I used Serial.print rather than Serial.printf as I haven't added a library to support it. so- Serial.print ("loop1"); Serial.println(count1); I would be very grateful for any suggestions as i'm at a bit of a dead end.

which core does this work on? official Arduino core, or the core by Earle Philhower?

Will it effects power consumption?

12:00 COM57 how many USP ports do you have, why so many?

Is this the official arduino rp2040 core or is it the community earle philhower rp2040 core

Your code also works on ESP32-C3 - without any modifications, it just runs both loops on same core. It's useful if you want the same code to run on various platforms, even single core, but make use of both cores if you have it...

I've always been under the assumption that you can't use both cores of an ESP32 if your using WiFi or Bluetooth as those systems are dedicated to one core if you enable them so your code is limited to the other core... Is that not true?

My Arduino 2.0.0 IDE does not show the "Tools/Arduino runs On" entry in the menue ??? and ARDUINO_RUNNING_CORE is not declared ?

Hi, I have 3 DS18B20 sensors connected to ESP32, how can I pass this sensor reading from one to another core. Can anyone help me? Is there any example to refer?

Can't quite figure out... are *all* esp32 dual core?

Show the s3 compiler options in the ide ffs

skip>>> 2m45s why the flash card,, count zero ,, william gibson

time to switch to 2.0

good explanation but the thumbnail not that good