for (;;) { } } gcjr:Reading the registers/state of another core. When the voltage on the input is beetween those values, you can expect undefined behaviour. 2 posts • Page 1 of 1. The program below measures ESP-32 interrupt delay. The main issue here is the way the interrupt handler work by storing a table of the ISR function pointer for each core. Register; Logout; Contact us; Board index English Forum Explore General Discussion; Interrupt low Latency - again. Each interrupt has a programmable priority level. Once Wifi is enabled, the latency can be a couple of. Choose the board, COM port, hold down the BOOT button, click upload and keep your finger on the BOOT button pressed. Espressif ESP32. The operating voltage of this SoC is 3. To learn more about interrupts with the ESP32, read the following tutorial: ESP32 Interrupts and Timers using Arduino IDE; Initialize Wi-Fi. and at T=9. Post by jfmateos » Mon Nov 07, 2016 9:03 am . Post by bmakovecki ». I'm using the following code: Code: Select all. NORA-W106 (ESP32-S3) NORA-W106 module. The PIR Sensor acts as an source for the external interrupt. But when the interrupt latency is longer than the narrowest pulse from ledc the edge polarity detection fails and the output-pair is wrong. The ESP32-C6 combines 2. Post by go4retro » Thu Jan 10, 2019 6:26 am . Interrupt low Latency - again. se » Wed Jun 16, 2021 9:17 am. I'm trying to implement a high level interrupt to reduce the interrupt latency and jitter. Post by jfmateos » Mon Nov 07, 2016 9:03 am . Espressif ESP32 Official Forum. IRQ Startup latency. ESP32-S3 GPIO interrupt latency is too high. Each pin can be used as a general-purpose I/O, or be connected to an internal peripheral signal. Post by ESP_igrr » Mon Nov 07, 2016 11:36 am . Postby jeromeh » Sun Feb 05, 2017 8:31 am. Espressif ESP32 Official Forum. 9usec. What is the difference between hardware interrupt and software. BTW, for the goal you're aiming for (measuring pulse durations), timers in GPIO ISRs are not the best solution on the ESP32 (mostly due to interrupt latency : the ESP32 CPU is a lot more complex than simple 8-bit micros). o. It needs to save the current CPU registers, program counter. The connections to the module are straightforward. When the timer finishes. I need a <1usec resolution to read the outputs of CMPSS on the comparator section and be ready to read again those outputs after 1usec. Post by jeromeh » Sun Feb 05, 2017 8:31 am . Espressif ESP32 Official Forum. Minimum extra latency is 0. At first, I thought the I2C was hanging in the ESP32 but I can see that the problem. I have one task at each core. 2 posts • Page 1 of 1. Re: ESP IDF get GPIO level at time of interrupt. The ESP-IDF OS supports pinning tasks to cores, which means that you assign one of the cores to run a particular task. These ESP32-C3 Hardware Timers, using Interrupt, still work even if other functions are blocking. Use it with a scope or a logic analyser: 2700000 served interrupts/sgreetings. Therefore, there is a lower limit to the timeout value of one-shot esp_timer. Espressif ESP32 Official Forum. In particular, for ESP32-WROVER module, call rtc_gpio_isolate (GPIO_NUM_12) before entering deep sleep, to reduce deep sleep current. Hi guys, I am implementing an interrupt handler for reception of data through the UART of the ESP32. Arduino Wiring-based Framework for the Espressif ESP32, ESP32-S and ESP32-C series of SoCs. In this case, the IO_MUX is used to connect these pads directly to the peripheral. We’ll cover how to publish to a single field and how to publish to multiple fields. I'm interested to see if the GPIO interrupt latency is more consistent than I have found on the ESP32. How about latency? Can I make interrupt to trigger more precisely (cca 1us delay would be fantastic)? Regards, Boris. and at T=9. Skip to content. 6. Normally, interrupts are written in C, but ESP-IDF allows high-priority interrupts to be written in assembly as well, resulting in very low interrupt latencies. wdt. ESP32-S3 GPIO interrupt latency is too high. This library enables you to use Interrupt from Hardware Timers on an ESP32-C3-based board. 5 posts • Page 1 of 1. Each interrupt has a certain priority level, most (but not all) interrupts are connected to the interrupt mux. Pyboard) achieve much lower interrupt latency (few us) but prohibit memory allocation in interrupt handlers. 2 (aditional saturation enable)+. After having issues with interrupt latency I've checked an older thread where it's described that interrupt. I think there has been a little bit of progress, although not specifically for this purpose: the GPIO drivers have been optimized a bit so if you use the ESP-IDF API, your interrupt latency should be a bit lower (but not as low as using the bare metal), and ESP-IDF now allows you to have high-prio assembly. ESP32 Interrupt. At 17uS, the esp32 responds to the event and sets an IO line to respond, which is too late. After having issues with interrupt latency I've checked an older thread where it's described that interrupt latency with C is around 2us. FAQ; Forum. Since core 0 is already used for those tasks, it is always best to use the second core 1. Core 0 is known as the “Protocol Core” or “PRO CPU. A detailed ESP32-C3 datasheet is. Each interrupt has a certain priority level, most (but not all) interrupts are connected to the interrupt mux. Minimum extra latency is 0. External Interrupt Latency. Board index English Forum Discussion Forum ESP32 Arduino; How to improve interrupt latency with Arduino/C. h> #include <HTTPClient. IRQ Startup latency. Typically, if using the Arduino AttachInterrupt thingy in setup () the interrupt will be attached to core1. ESP32 external interrupt latency. e. Depending on the project at hand I switch between two development environments: either ESP-IDF, running under Eclipse on Ubuntu 18. Each interrupt has a fixed priority, most (but not all) interrupts are connected to the interrupt matrix. IRQ Startup latency. The polling method is like a salesperson. wdt. Unlike on other micropython ports, on the ESP32 the time between a hardware interrupts occurring and Python handlers being called is irregular and. Espressif ESP32 Official Forum. Closed tannewt pushed a commit to tannewt/circuitpython that referenced this issue May 29, 2020. 4, hd:ESP32-S3 when a pulse is detected by one io, an spi transaction will be triggered. Espressif ESP32 Official Forum. we are doing some stuff with an external RF transceiver and need to respond to its interrupts as fast as (technically) possible. Post by bmakovecki ». GPIO Interrupt Latency - once more. g. The interrupt source is a GPIO that connects to pulse-per-second signal from a GPS module. . Improving Overall Speed. Interrupt low Latency - again. 5 posts • Page 1 of 1. At some time later (the latency) you then detect the new message in the queue. Here is a skeleton code, to trigger an interrupt via an external signal on your ESP32 board with MicroPython :. ESP32-S3 GPIO interrupt latency is too high. External Interrupt Latency. esp32 GPIO interrupt latency. You're already stretching the limits of what the ESP32 can do, I'm surprised the plain polling approach works this fast. Overview. 25VDD and the minimum voltage for the high input os 0. Moreover, they are much more precise (certainly depending on clock frequency accuracy) than other software timers using millis() or micros(). An esp32 can do the job but is overkill and will be adding a complexity you do not need when learning C. Creating and starting a timer, and dispatching the callback takes some time. The ESP32-S3 has two cores, with 32 interrupts each. I think there has been a little bit of progress, although not specifically for this purpose: the GPIO drivers have been optimized a bit so if you use the ESP-IDF API, your interrupt latency should be a bit lower (but not as low as using the bare metal), and ESP-IDF now allows you to have high-prio assembly. ESP32 Interrupt Latency Measurement Interrupt Latency – is the time it takes the CPU to respond to a specific interrupt signal. Sensor Shell Module Sample. external interrupt jitter. g. Post by go4retro » Thu Jan 10, 2019 6:26 am . 2 us (when the CPU frequency is 240 MHz and frequency scaling is not enabled). Setting a bit and polling this bit in another task within an infinite loop is faster (2 us), but cannot be a real option, because this is waste of resources and prevents from deep sleep options. ESP32 GPIO Interrupts. h> // Include Serial Peripheral. Maximum voltage for low input is 0. As most of the base stuff runs on CPU0, CPU1 has fewer things to mess with the latency. One is to use the semaphore (s. External Interrupt Latency. 2 us (when the CPU frequency is 240 MHz and frequency scaling is not enabled). It’s a measure for the response time of an interrupt and it’s desired to be as small as. For some reason, the traceback for case C could not be decoded by EspExceptionDecoder. A event handler is registered and can be called correctly, but the. Pete. framework-espidf. Espressif ESP32 Official Forum. greetings sdk: IDF V4. The arduino IDE completely abstracts the linking, interrupt tables and all that. Now, if we use a timer, we can use a callback function to get triggered every interval. The MIPS chip I'd like to replace currently does it in 225 ns at 80 MHz (18 clock cycles), and any increase is likely to make things no longer work. If an interrupt request fires while the program is running a critical section, the request is put on hold and serviced only when the critical section is done. Interrupt low Latency - again. The cache guards can't know if you're trying to access something in flash or PSRAM; it will crash if your interrupt happens to read or write that. Re: handling GPIO interrupts. But if they are happening simultaneously, then the one with the higher priority runs first and the lower priority gets queued. ; ESP32: The ESP32. The code is functional, but I can't work with. :49 am. sdk: IDF V4. Alternatively, it may be enough to run the gpio_install_isr_service call on a task that is pinned to CPU1. For this tutorial we’ll program the ESP32 using the Arduino core. External Interrupt Latency. txt" below you can see some details. GPIO Interrupt Latency - once more. ESP8266EX and ESP32 are some of our products. 4, hd:ESP32-S3 when a pulse is detected by one io, an spi transaction will be triggered. Post by jfmateos » Mon Nov 07, 2016 9:03 am . With Wifi *disabled*, I get a control loop latency of ~6ms . Top. I seem to remember recent ESP-IDF versions have some allowances to also run C high-level interrupts, but I don't have the details on that. Depending on the project at hand I switch between two development environments: either ESP-IDF, running under Eclipse on Ubuntu 18. The result is incorrect counting. These ESP boards are. I'm using ESP32 Arduino IDE. If the ISR for interrupt 0 is executing and interrupt 1 occurs, it will be held until interrupts are turned on again after I0 has finished. Now I have found the time to do it for myself and with the ESP32 and some other platforms. greetings sdk: IDF V4. After that you get a cylcetime of ~300ns (disable interrupts for core 0). The Full code Listing. After having issues with interrupt latency I've checked an older thread where it's described that interrupt. IRQ Startup latency. Espressif ESP32 Official Forum. The IPC feature allows execution of a callback function on the target core in either a task context, or an interrupt context. My code is bellow. In the Arduino IDE, we use a function called attachInterrupt () to set an interrupt on a pin by pin basis. I use an ADPS-9960 for gesture control which triggers an external interrupt. If you are not using FreeRTOS software timers, set that macro to 0. Interrupt latency on the ESP32 is in the order of microseconds, unfortunately; there's a fair amount of prologue going on. I am seeing a similar issue as noted here:. I think there has been a little bit of progress, although not specifically for this purpose: the GPIO drivers have been optimized a bit so if you use the ESP-IDF API, your interrupt latency should be a bit lower (but not as low as using the bare metal), and ESP-IDF now allows you to have high-prio assembly interrupt handlers without having to copy-paste the ESP-IDF vector/startup code integrally. [中文] The Xtensa architecture supports 32 interrupts, divided over 7 priority levels from level 1 to 7, with level 7 being an non-maskable interrupt (NMI), plus an assortment of exceptions. This is double the 40 MHz default value and will double the speed at which code is loaded or executed from flash. 9usec. RAM speeds are 150nS - so that was the target; for a modern 200Mhz dual core xtensa it should be no trouble. An interrupt service routine should be as light as possible so that it can service an interrupt quickly. We’ll use the timer compare match interrupts (COMPA & COMPB) at the same time. FAQ; Forum. Re: External Interrupt Latency. Top. Now I have found the time to do it for myself and with the ESP32 and some other platforms. If you use a delay (5) inside the ISR, you will be blocking the processor for at least 5ms, which for a computer is a lot of time. Espressif ESP32 Official Forum. 04 in a VirtualBox. Imagine now that we have an interrupt being fired when the signal goes low to high. The ESP32 is communicating with a PIC16 microcontroller through an I2C bus. At 17uS, the esp32 responds to the event and sets an IO line to respond, which is too late. But if they are happening simultaneously, then the one with the higher priority runs first and the lower priority gets queued. 1 was: "Some high-speed digital functions (Ethernet, SDIO, SPI, JTAG, UART) can bypass the GPIO Matrix for better high-frequency digital performance. An OS typically provides multitasking, synchronization, Interrupt and Event Handling, Input/ Output, Inter. Hi, I'm using a GPIO pin as a external interrupt, responding to negedge events. Post by mTron47 » Fri Jul 13, 2018 3:39 pm . RF operations of the ESP32 SoC require time-sensitive and interrupt-based software which can be complex. Now I have found the time to do it for myself and with the ESP32 and some other platforms. How to improve interrupt latency with Arduino/C. I think there has been a little bit of progress, although not specifically for this purpose: the GPIO drivers have been optimized a bit so if you use the ESP-IDF API, your interrupt latency should be a bit lower (but not as low as using the bare metal), and ESP-IDF now allows you to have high-prio assembly. Through oscillometer I found the interval between the pulse and spi cs signal was as much as 100~200 us, while this thread says the interrupt latency can be reduced to about 2 us. Espressif ESP32 Official Forum. As far as I know, ESP32 has no Schmitt trigger inputs, so what you get is the expected behaviour. Writing to, and then subsequently reading from, the timer command queue adds an additional latency. Post by mTron47 » Fri Jul 13, 2018 3:39 pm . That needs 2 µs latency to start the waiting task RTOS_2 in core 0. jeromeh Posts: 31 Joined: Thu Dec 22, 2016 5:41 am. External Interrupt Latency. An Operating system (OS) is nothing but a collection of system calls or functions which provides an interface between hardware and application programs. Use it with a scope or a logic analyser: 2700000 served interrupts/s greetings. Would it be possible to start a hardware timer in the first interrupt handler and then see how many ticks have elapsed in the second one? That feels as if it should give less latency and better resolution. Each interrupt has a certain priority level, most (but not all) interrupts are connected to the interrupt mux. Re: Critical attention to GPIO interrupts. It also takes 26uS to process the IRQ body, though I am using QueueSendfromISR in the. There are actually SEI & CLI assembly instructions in the instruction set of Arduino’s. So, make sure you have the ESP32 add-on installed in your. txt" below you can see some details. As an example, we’ll detect motion using a PIR motion sensor: when motion is detected, the ESP8266 starts a timer and turns an LED on for a predefined number of seconds. I am seeing a similar issue as noted here:. Well that sounds like a shortcoming. Use Interrupts - Triggering interrupts on specific communication events. Extra latency depends on a number of factors, such as the CPU frequency, single/dual core mode, whether or not frequency switch needs to be done. To attach an interrupt, we will use the attchInterrupt () macro. Andreas Spiess made a great video on the ESP32. I'm setting another GPIO pin to high when entering the event handler, and. The objective of this esp32 arduino tutorial is to explain how to handle external interrupts using the ESP32 and the Arduino core. Board index English Forum Discussion Forum ESP32 Arduino; How to improve interrupt latency with Arduino/C. println (xPortGetCoreID ()); You should see "Current CPU core 1" as output (the cores are normally numbered 0 and 1). Quadrature Decoder Sensor. Postby [email protected] ESP32-S3 is connected to WiFi. To solve this problem, you must activate the desired effect and this is done with the following command. Through oscillometer I found the interval between the pulse and spi cs signal was as much as 100~200 us, while this thread says the interrupt latency can be reduced to about 2 us. It also takes 26uS to process the IRQ body, though I am using QueueSendfromISR in the. When the Wifi is working the edge detection and the callback function execution is delayed. And it has ability to lock and load lines which is useful to create SW breakpoints in Flash and have ability to minimize interrupt latency; Interrupt Controller: Highest priority interrupt has a specific register set to minimize interrupt latency; Sub priorities and Multiple priorities for each vector; Fully programmable interrupt controller is. The purpose of the IWDT is to ensure that interrupt service routines (ISRs) are not blocked from running for a prolonged period of time (i. The timer_u32() is an alternative for the esp_timer_get_time() function as described in Epressif Documentation. Writing into a queue in order to handle the interrupt in another task takes way too much time (about 13 us). Now I have found the time to do it for myself and with the ESP32 and some other platforms. INUM_GPIO (4) is the index for a GPIO interrupt, and this bit will be set in INTERRUPT if a GPIO interrupt has occured. Skip to content. There isn't any other device on the bus so when the PIC16 has new data available it generates a 50us low pulse on the SCL line, the ESP32 detects this pulse and starts reading data. Interrupt Latency Requirements Encoder requires low latency response to changes of the signals. ESP_igrr Posts: 1968 Joined: Tue Dec 01, 2015 8:37 am. But anyway, we know for sure that the dedicated external interrupt pins. 5 posts • Page 1 of 1. Register; Logout; Contact us; Board index English Forum Explore General Discussion; Interrupt low Latency - again. Setting a bit and polling this bit in another task within an infinite loop is faster (2 us), but cannot be a real option, because this is waste of resources and prevents from deep sleep options. and at T=9. A event handler is registered and can be called correctly, but the interrupt latency seems pretty unpridictable. ESP_igrr Posts: 1970 Joined: Tue Dec 01, 2015 8:37 am. 11:42 am. within the loop, the WiFi connection just sits idle in the background. mcpwm_isr_register (MCPWM_UNIT_0, isr_handler, NULL, ESP_INTR_FLAG_IRAM, NULL ); in interrupt I have simple float operation as : Code: Select all. Enabling power management features comes at the cost of increased interrupt latency. The setup code We will start by declaring the pin where the interrupt will be attached on a global. Interrupt Latency. I will focus on describing how to refactor a. I am seeing a similar issue as noted here:. Hi, I'm using a GPIO pin as a external interrupt, responding to negedge events. Post by FL0WL0W » Mon Sep 06, 2021 12:00 pm . This is useful for interrupts which need a guaranteed minimum execution latency, as flash write and erase operations can be slow (erases can take tens or hundreds of milliseconds to. No, the problem is in that: With 1. There the latency varies between 4us and 38us. 04 in a VirtualBox. This method is useful for some simple callbacks which aim for lower latency. I think there has been a little bit of progress, although not specifically for this purpose: the GPIO drivers have been optimized a bit so if you use the ESP-IDF API, your interrupt latency should be a bit lower (but not as low as using the bare metal), and ESP-IDF now allows you to have high-prio assembly. (186) boot. esp32 GPIO interrupt latency. Alternatively, it may be enough to run the gpio_install_isr_service call on a task that is pinned to CPU1. ESP32 GPIO Interrupts. Pete. At 17uS, the esp32 responds to the event and sets an IO line to respond, which is too late. The esp_intr_alloc abstraction exists to hide all these. It manages the hardware resources of a computer and hosting applications that run on the computer. Juraj: Ethernet. Here is the source to show superfast interaction: External interrupt detected by task Core1 --300ns--> RTOS_2 (core 0) reacts. MS5837 Sensor Sample. 2 posts • Page 1 of 1. Post by ESP_Sprite » Sun Nov 18, 2018 3:11 am . Home; Quick links. Extra latency depends on a number of factors, such as the CPU frequency, single/dual core mode, whether or not frequency switch needs to be done. The MIPS chip I'd like to replace currently does it in 225 ns at 80 MHz (18 clock cycles), and any increase is likely to make things no longer work. At first, I thought the I2C was hanging in the ESP32 but I can see that the problem is. A driver can allocate an interrupt for a. But this is only applicable if you are using some of the RF features such as Wi-Fi or BLE. ISR inside a class as a static class function with static variables. Post by MiguelMagno » Mon Aug 21, 2023 10:31 pm . It also takes 26uS to process the IRQ body, though I am using QueueSendfromISR in the. GPIO Interrupt Latency - once more. I2C. Post by go4retro » Thu Jan 10, 2019 6:26 am . There are different solutions. But technically the edge detection inside the CPU stores the values in a register somewhere and compares them to figure out if an edge occured between cycles. Post by FL0WL0W » Mon Sep 06, 2021 12:00 pm . Follow 3 min read · Feb 8, 2022 1 A deep dive into the ESP32, the IDF and docs, hoping it can perform better. g. Each interrupt has a fixed priority, most (but not all) interrupts are connected to the interrupt matrix. The operating system switches task base on priority. Arduino PCINT (Pin Change Interrupts) by Khaled Magdy. When the Arduino IDE starts sending the code, you can release the button and wait for the flashing process to be completed. sei(): Set interrupt global enable flag bit (re-enable interrupts after being disabled). Because there are more interrupt sources than. With Wifi *disabled*, I get a control loop latency of ~6ms . Lately, I've been working on a project that consists of programming a Z80 with 8 address and data lines, the clock is done with ledc, it has two external interrupts on the Z80's WR and RD pins --> ESP32. Hi, I'm using a GPIO pin as a external interrupt, responding to negedge events. Writing into a queue in order to handle the interrupt in another task takes way too much time (about 13 us). However, if interrupts are disabled for lengthy times, either by your code or another library, Encoder may miss a change. An ESP32 timer group should be identified using timer_group_t. A high interrupt latency, however, may not be acceptable for certain low-latency use-cases. Post by ESP_igrr » Mon Nov 07, 2016 11:36 am . Post by mTron47 » Fri Jul 13, 2018 3:39 pm . The ESP32 has two cores, with 32 interrupts each. greetings sdk: IDF V4. The arduino IDE completely abstracts the linking, interrupt tables and all that. Re: Wifi Driver Receive Buffer Access/Interrupt. Because. Now I believe timer interrupt will be a better option as we will not need the task to be running all the time. The code is functional, but I can't work with. 04 in a VirtualBox. This is double the 40 MHz default value and doubles the speed at which code is loaded or executed from flash. Skip to content. Application Controlled Deferred Interrupt Handling Application controlled deferred interrupt handling is so called because each interrupt that uses this method executes in the context of a task created by the application writer. Interrupt latency on the ESP32 is a little higher than ESP8266, although there are also a lot of other variables which can effect interrupt timing. Post by edigi32 » Tue Feb 26, 2019 9:57 am . void timerAttachInterruptArg (hw_timer_t. ESP32-S3 GPIO interrupt latency is too high. This time between the hardware IRQ and starting the execution of the ISR is called the Interrupt Latency and it’s demonstrated in more detail in the tutorial linked below. Board index English Forum Discussion Forum ESP32 Arduino; How to improve interrupt latency with Arduino/C. Reduce external interrupt latency. The 1 PPS signal is connected to a second timer (T2) that simply "captures" its value in a register and also triggers an interrupt, at which time we also take a snapshot of T1's value. The Full code Listing. Interrupt low Latency - again. Board index English Forum Discussion Forum ESP-IDF; Reduce external interrupt latency. I write the interrupt handler in assemble and register the interrupt in app_main with priority level 5. Post by jeromeh » Sun Feb 05, 2017 8:31 am . For interrupt handlers which need to execute when the cache is disabled (e. Improving Overall Speed. So my next step is to call an interrupt in assembly which required to use ESP32's higher priority levels. The ESP32-S3 is based on an Xtensa® LX7 series microprocessor. esp32 GPIO interrupt latency. Return. ESP_igrr Posts: 2012 Joined: Tue Dec 01, 2015 8:37 am. To create an interrupt, call attachInterrupt () and pass as arguments the GPIO interrupt pin, the. GPIO Interrupt Latency - once more. ESP32 external interrupt latency. init (5); Thank you very much i was researching this problem for 2 days you saved me from a big mess. Now, the ESP32 is flashed with the new firmware. At its heart, there's a dual-core or single-core. Without seeing and debugging the full code it's hard to tell what the problem might be. Unfortunately, interrupts on the ESP32 are a bit more complex than on an AVR (mostly because we need to do a bunch more context switching things, as well as the need to figure out what interrupt is triggered. External Interrupt Latency. So if other interrupts take a maximum of 15 µs (eg, some libraries), then a baud rate of 57600 ought to be possible. Context saving and restoration is a process that the CPU needs to do just to smoothly switch between main program execution and ISR handlers. d98151a. Espressif ESP32 Official Forum. On a congested wireless channel (meaning lots of other devices broadcasting) you'd routinely see 100+ ms latencies as your devices have to wait for a free radio slot. I am seeing a similar issue as noted here:. None of them is induced by the abort in your modified esp_timer_impl_set_alarm code. Setting a bit and polling this bit in another task within an infinite loop is faster (2 us), but cannot be a real option, because this is waste of resources and prevents from deep sleep options. Each interrupt has a fixed priority, most (but not all) interrupts are connected to the interrupt matrix. Now I have found the time to do it for myself and with the ESP32 and some other platforms. Ideally, we would want this time to be less. Using the SDK indeed does restrict the interrupt bandwidth to around 200khz. Post by go4retro » Thu Jan 10, 2019 6:26 am . Plus we need to define an instance of this static variable. Once Wifi is enabled, the latency can be a couple of. Setting a bit and polling this bit in another task within an infinite loop is faster (2 us), but cannot be a real option, because this is waste of resources and prevents from deep sleep options. At 17uS, the esp32 responds to the event and sets an IO line to respond, which is too late. Alternatively, it may be enough to run the gpio_install_isr_service call on a task that is pinned to CPU1. Post by ESP_igrr » Mon Nov 07, 2016 11:36 am . Measure its duration using the task set up in pt. I think there has been a little bit of progress, although not specifically for this purpose: the GPIO drivers have been optimized a bit so if you use the ESP-IDF API, your interrupt latency should be a bit lower (but not as low as using the bare metal), and ESP-IDF now allows you to have high-prio assembly. ESP_igrr Posts: 2066 Joined: Tue Dec 01, 2015 8:37 am. Initialize a 'direct' interrupt handler. First, interrupt handlers need to be defined using the IRAM_ATTR attribute in order to ensure that they're already loaded into instruction memory (IRAM). I think there has been a little bit of progress, although not specifically for this purpose: the GPIO drivers have been optimized a bit so if you use the ESP-IDF API, your interrupt latency should be a bit lower (but not as low as using the bare metal), and ESP-IDF now allows you to have high-prio assembly. 2 us (when the CPU frequency is 240 MHz and frequency scaling is not enabled). The ESP32-S2 has one core, with 32 interrupts. Use vTaskSuspend () at the start of the loop to have the task wait till it's woken up. void taskthingy ( void *pvparemeters ) { //assign interrupt here and interrupt will go onto the core the task has been assigned to. Minimum extra latency is 0. All I need is to grab the hardware timer value and store it. static uint32_t lasthandshaketime; uint32_t. Raising the level, the interrupt handler can reduce the timer processing delay. Each interrupt has a programmable priority level. This is required to latch the data into the DAC registers with the CS line. 4, hd:ESP32-S3. STM32 Interrupt Latency.