You can also test that your interrupt handler is running on core 1 by calling this from it. In this tutorial, we will learn to use ESP-MESH network using the painlessMesh library and ESP32/ESP8266 NodeMCU. This is solved by //looking at the time between interrupts and refusing any interrupt too close to another one. STM32 ESP32 ARDUINO PIC Electronics. Register; Logout; Contact us; Board index English Forum Explore General Discussion; Interrupt low Latency - again. Create the function that will be executed when. On suitable hardware MicroPython offers the ability to write interrupt handlers in Python. e. I'm trying to implement a high level interrupt to reduce the interrupt latency and jitter. This library enables you to use Interrupt from Hardware Timers on an ESP32-C3-based board. How to improve interrupt latency with Arduino/C. 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. ESP32-S3 GPIO interrupt latency is too high. println (xPortGetCoreID ()); You should see "Current CPU core 1" as output (the cores are normally numbered 0 and 1). BlueRetro being a universal adapter with auto-detect at run time it's not possible to compile two versions. NORA-W106 (ESP32-S3) NORA-W106 module. That needs 2 µs latency to start the waiting task RTOS_2 in core 0. com Perhaps those functions are executed very often, or have to meet some application requirements for latency or throughput. Post by ESP_igrr » Mon Nov 07, 2016 11:36 am . Then the timer sends a signal to either a display or LED and starts the counting again. Writing into a queue in order to handle the interrupt in another task takes way too much time (about 13 us). MS5837 Sensor Sample. The connections to the module are straightforward. 4 GHz Wi-Fi and Bluetooth 5 (LE) with a long-range support. Main Differences. I am seeing a similar issue as noted here:. ISR inside a class as a static class function with static variables. I have done a measurement and delay from external. Espressif ESP32 Official Forum. 04 in a VirtualBox. Espressif ESP32 Official Forum. The objective of this esp32 arduino tutorial is to explain how to handle external interrupts using the ESP32 and the Arduino core. Connect I2C SCL and SDA lines to the same on the MCU. Enable some one-off interrupt, such as GPIO interrupt. greetings sdk: IDF V4. 35uS, the master brings the line high. This process is generally time consuming (currently clocks in at approximately a few microseconds on the ESP32) and is not suited for High Level interrupts since they're. Use vTaskSuspend () at the start of the loop to have the task wait till it's woken up. 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. Depending on the project at hand I switch between two development environments: either ESP-IDF, running under Eclipse on Ubuntu 18. Espressif Homepage;. 04 in a VirtualBox. 2 us (when the CPU frequency is 240 MHz and frequency scaling is not enabled). 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. We can use any GPIO pin for interrupts. IRQ Startup latency. Here is the source to show superfast interaction: External interrupt detected by task Core1 --300ns--> RTOS_2 (core 0) reacts. When the Wifi is working the edge detection and the callback function execution is delayed. To enable pin change interrupt on a pin, we’ll need to manipulate the PCICR register: The last three bits of this register are control bits for enabling a PCINT group. txt" below you can see some details. ESP_igrr Posts: 2066 Joined: Tue Dec 01, 2015 8:37 am. We need to take some action when the interrupt is triggered (here: read a digital input). STM32 Interrupt Latency. Through IO MUX, RTC IO MUX and the GPIO matrix, peripheral input signals can be from any IO pins, and. greetings sdk: IDF V4. Espressif ESP32 Official Forum. After having issues with interrupt latency I've checked an older thread where it's described that interrupt. 11 b/g/n/ax), Bluetooth 5 (LE), and a IEEE 802. WiFive. The following optimizations improve the execution of nearly all code, including boot times, throughput, latency, etc: Set CONFIG_ESPTOOLPY_FLASHFREQ to 80 MHz. At 17uS, the esp32 responds to the event and sets an IO line to respond, which is too late. Writing into a queue in order to handle the interrupt in another task takes way too much time (about 13 us). IRQ Startup latency. ESP32 interrupt latency is long and irregular #3894. Home; Quick links. After having issues with interrupt latency I've checked an older thread where it's described that interrupt latency with C is around 2us. and at T=9. ESP32-S3 GPIO interrupt latency is too high. 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. Espressif ESP32 Official Forum. 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. Serial. 35uS, the master brings the line high. When PCIE0 (bit 0) is set, then the. These interrupts are defined as zero-latency interrupts. Re: handling GPIO interrupts. Re: himem page change delays isr. 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. Install Drivers - Allocating ESP32’s resources for the UART driver. 35uS, the master brings the line high. 5 posts • Page 1 of 1. 4, hd:ESP32-S3 when a pulse is detected by one io, an spi transaction will be triggered. ESP32-S3 GPIO interrupt latency is too high. Here is the source to show superfast interaction: External interrupt detected by task Core1 --300ns--> RTOS_2 (core 0) reacts. FAQ; Forum. 35uS, the master brings the line high. 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. The operating system switches task base on priority. Interrupt Latency Requirements Encoder requires low latency response to changes of the signals. Top. MPR Pressure Sensor. 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. Each interrupt has a fixed priority, most (but not all) interrupts are connected to the interrupt matrix. 1 was: "Some high-speed digital functions (Ethernet, SDIO, SPI, JTAG, UART) can bypass the GPIO Matrix for better high-frequency digital performance. Transmitter code. I would like to know the interrupt latency for an external pin interrupt in ESP32. An interrupt service routine should be as light as possible so that it can service an interrupt quickly. Because there are more interrupt sources than interrupts, sometimes it makes sense to share an interrupt in multiple drivers. 4 radio for ZigBee and Thread. 3 V. Skip to content. and at T=9. Post by edigi32 » Tue Feb 26, 2019 9:57 am . Reduce external interrupt latency. I wonder if anyone has by any chance measured the pin-to-pin latency for a minimal interrupt handler (e. and wakeup latency. Depending on the project at hand I switch between two development environments: either ESP-IDF, running under Eclipse on Ubuntu 18. It’s a measure for the response time of an interrupt and it’s desired to be as small as. A event handler is registered and can be called correctly, but the. The ESP32-S2 has one core, with 32 interrupts. When I trigger an interrupt during the delay function the interrupt stops working. 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. Now I have found the time to do it for myself and with the ESP32 and some other platforms. begin (115200); Serial. 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. (Accessing DRAM or other internal memory is fine; your data doesn't have to be in IRAM, just in internal RAM. Post by jfmateos » Mon Nov 07, 2016 9:03 am . The syntax looks like below. For example, a timer can be used to generate a. I would like to know the interrupt latency for an external pin interrupt in ESP32. The next 1, 2 or 3. Internally, esp_timer uses a 64-bit hardware timer, where the implementation depends on the target. There are no native software interrupts in Arduino UNO (Atmega328p) microcontroller. Re: handling GPIO interrupts. Typically, if using the Arduino AttachInterrupt thingy in setup () the interrupt will be attached to core1. we are doing some stuff with an external RF transceiver and need to respond to its interrupts as fast as (technically) possible. Post by go4retro » Thu Jan 10, 2019 6:26 am . Depending on the project at hand I switch between two development environments: either ESP-IDF, running under Eclipse on Ubuntu 18. Interrupt latency on the ESP32 is in the order of microseconds, unfortunately; there's a fair amount of prologue going on. This behavior was not happening with a Arduino Nano, I wanted to replace the nano with the ESP32. At its heart, there's a dual-core or single-core. Home; Quick links. I'm setting another GPIO pin to high when entering the event handler, and. Post by ESP_Sprite » Sun Nov 18, 2018 3:11 am . With ESP32, we can configure all the GPIO pins as hardware interrupt sources. I want to know if it is a normal behavior of F280049C operating at 100Mhz. 75xVDD. External Interrupt Latency. The time between each pulse is anything. Deleting a Driver - Freeing allocated resources if a UART communication is no longer required. Writing interrupt handlers. Post by go4retro » Thu Jan 10, 2019 6:26 am . println ("Monitoring interrupts: "); Next, since we are going to be working with an external pin interrupt, we need to configure the previously declared pin number as an input pin. The problem is: there is some delay between the interrupt being triggered and our taking the appropriate action. 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. But when the interrupt latency is longer than the narrowest pulse from ledc the edge polarity detection fails and the output-pair is wrong. Without other libraries, on Teensy or Arduino (with the issue 776 fix), interrupt latency is about 3 to 4 µs. The ISR handler should clear the interrupt source if it’s required (Some don’t need to be cleared like the SysTick). Interrupts sensitive to pin logical level take into account GPIO_ACTIVE_LOW flag. It would be good to find a way to have interrupt handlers on the ESP32 have consistent and low latency. Arduino and ESP8266: The Arduino boards as well as the ESP8266 in general do not have an internal DAC and therefore you would have to build an DAC with external components. I'm detecting another delay related with the GPIO interrupts from ESP32. An Operating system (OS) is nothing but a collection of system calls or functions which provides an interface between hardware and application programs. An stm32 is "worse" in a sense that you can easily use the arduino IDE to work with esp32, but it is different with stm chips. 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. Hi, I'm using a GPIO pin as a external interrupt, responding to negedge events. Espressif ESP32 Official Forum. bmakovecki Posts: 4 Joined: Fri Nov 03, 2017 9:20 pm. For this tutorial we’ll program the ESP32 using the Arduino core. GPIO Interrupt Latency - once more. and at T=9. Re: ESP External Clock. A driver can allocate an interrupt for a. greetings sdk: IDF V4. we are doing some stuff with an external RF transceiver and need to respond to its interrupts as fast as (technically) possible. IRQ Startup latency. 04 in a VirtualBox. You could look into the dedicated GPIO module; from what I know the interrupts of those are a bit faster. I am seeing a similar issue as noted here:. Transmitter code. Skip to content. GPIO Summary. ESP32 external interrupt latency. The ESP32 has two cores, with 32 interrupts each. And, because interrupts have things in common with deep-sleep, we w. implement hard pin interrupts on the esp32 to enable faster response times; check for pending soft interrupts in sleep_us(); this would need to be done in a smart. Hi, I am having trouble with the external interrupt latency being very inconsistent. Re: ESP32-S3 GPIO interrupt latency is too high. A event handler is registered and can be called correctly, but the. Home; Quick links. The ESP32 has two I2C channels and any pin can be set as SDA or SCL. 1. Available now!Ever since I finished working on the latency tests & improvement, I've been working on trying to free up the 2nd core from its FreeRTOS duty by running it bare metal as originally demonstrated by @Daniel with #Bare metal second core on ESP32. The timer_u32. Now I have found the time to do it for myself and with the ESP32 and some other platforms. The problem is, i have a huge latency of 200-250ms between input signal on transmitting ESP32 and receiving ESP32, and i would like to eliminate this or lower it as far as possible. I'm using the following code: Code: Select all. The latency and jitter you can expect from a connection to an ESP32 depends heavily on the availability of free WiFi ether on the chosen channel. 5 posts • Page 1 of 1. Hi, I'm using a GPIO pin as a external interrupt, responding to negedge events. These ESP32-C3 Hardware Timers, using Interrupt, still work even if other functions are blocking. Normally, interrupts are written in C, but ESP. It has integrated 2. At 17uS, the esp32 responds to the event and sets an IO line to respond, which is too late. Espressif ESP32 Official Forum. My code is bellow. My code is bellow. I only have 1 interrupt setup to trigger on any edge and I am seeing anywhere from 2us to. attachInterrupt(GPIOPin, ISR, Mode); This function accepts three arguments: GPIOPin – sets the GPIO pin as the interrupt pin, which tells ESP32 which pin to monitor. 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 ESP32 understandably doesn't like having to load code from flash to RAM in order to service an interrupt. Minimum extra latency is 0. A driver can allocate an interrupt for a. Re: Comment about low-latency interrupts #52669. These ESP boards are. At 17uS, the esp32 responds to the event and sets an IO line to respond, which is too late. 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. CTR with CBC-MAC Protocol (CCMP) is used to protect the action frame for security. 04 in a VirtualBox. 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. As far as I know, ESP32 has no Schmitt trigger inputs, so what you get is the expected behaviour. Register; Logout; Contact us; Board index English Forum Explore General Discussion; Interrupt low Latency - again. Post by tankist » Thu Feb 10, 2022 7:08 am . Alternatively, it may be enough to run the gpio_install_isr_service call on a task that is pinned to CPU1. ESP32 Interrupt. ESP32-S3 GPIO interrupt latency is too high. I'm using the following code: Code: Select all. The ESP32-C6 combines 2. I suspect the latency comes from the SDK, in the management of interrupt handlers. 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. The ESP32-S3 is based on an Xtensa® LX7 series microprocessor. Interrupt Latency is defined to be the time between the actual interrupt request ( IRQ) signal and the CPU starting to execute the first instruction of the ( ISR) interrupt handler. Overview The ESP32 has two cores, with 32 interrupts each. ESP32 Interrupt Latency Measurement Interrupt Latency – is the time it takes the CPU to respond to a specific interrupt signal. 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. In this case, the IO_MUX is used to connect these pads directly to the peripheral. o. The support for zero. Once Wifi is enabled, the latency can be a couple of. I am seeing a similar issue as noted here:. 35uS, the master brings the line high. Because there are more interrupt sources than interrupts, sometimes it makes sense to share an interrupt in multiple drivers. Optimization efforts should be targeted at these particular functions. I write the interrupt handler in assemble and register the interrupt in app_main with priority level 5. We have some external event that triggers an interrupt (here: INT0 on pin change). wdt. The polling method is like a salesperson. I would like to know the interrupt latency for an external pin interrupt in ESP32. 5 posts • Page 1 of 1. Post by bmakovecki ». Without seeing and debugging the full code it's hard to tell what the problem might be. Writing into a queue in order to handle the interrupt in another task takes way too much time (about 13 us). External Interrupt Latency. You can’t measure it, because the next operation might take a little longer! You don’t mention a. We are using two external interrupts on the esp32, one interrupt is attached to core 1 (this is a high level interrupt on GPIO_NUM_35) and the other one is a low level interrupt which is tied to core 0 on GPIO_NUM_27. To create an interrupt, call attachInterrupt () and pass as arguments the GPIO interrupt pin, the. At some time later (the latency) you then detect the new message in the queue. Now, if we use a timer, we can use a callback function to get triggered every interval. In the interrupt handler itself I only set a variable that causes the execution of a function in the loop. A event handler is registered and can be called correctly, but the. When an interrupt is triggered, the processor halts the execution of the main program. 35uS, the master brings the line high. External Interrupt Latency. ESP-NOW is a kind of connectionless Wi-Fi communication protocol that is defined by Espressif. Depending on the project at hand I switch between two development environments: either ESP-IDF, running under Eclipse on Ubuntu 18. This is double the 40 MHz default value and will double the speed at which code is loaded or executed from flash. [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. The tests were performed on a DFRobot’s ESP-WROOM-32 device integrated in a ESP32 FireBeetle board. 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. Maximum voltage for low input is 0. 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. FAQ; Forum. These ISRs are designed for performance-critical interrupt handling and do not go through common interrupt handling code. ESP32-C3 features four predefined power modes that not only enable developers to fulfill the requirements of various IoT application scenar- ios but also pass rigorous power consumption. I am seeing a similar issue as noted here:. Espressif ESP32 Official Forum. 3 or 5V power and ground. Use it with a scope or a logic analyser: 2700000 served interrupts/sgreetings. Espressif ESP32 Official Forum. When the timer finishes. Each pin can be used as a general-purpose I/O, or be connected to an internal peripheral signal. Re: External Interrupt Latency. Post by mTron47 » Fri Jul 13, 2018 3:39 pm . 04 in a VirtualBox. Interrupt low Latency - again. The ESP32 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. . 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). and at T=9. IRQ Startup latency. Espressif ESP32 Official Forum. Preventing ISRs from running in a timely manner is undesirable as it can increase ISR latency, and also prevent task switching (as task switching is executed form an ISR). 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. There are actually SEI & CLI assembly instructions in the instruction set of Arduino’s. You're already stretching the limits of what the ESP32 can do, I'm surprised the plain polling approach works this fast. Post by go4retro » Thu Jan 10, 2019 6:26 am . 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. and it should be PubSubClient client (net); 1 Like. 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. Espressif ESP32 Official Forum. bmakovecki Posts: 4 Joined: Fri Nov 03, 2017 9:20 pm. Once Wifi is enabled, the latency can be a couple of. Espressif ESP32 Official Forum. We can enable interrupt on any of these GPIO pins by. 5 posts • Page 1 of 1. The ESP32 chip features 34 physical GPIO pins (GPIO0 ~ GPIO19, GPIO21 ~ GPIO23, GPIO25 ~ GPIO27, and GPIO32 ~ GPIO39). 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. Postby Xtensa2C » Sun May 31, 2020 9:56 am. Post by mTron47 » Fri Jul 13, 2018 3:39 pm . The only way you are going to get microsecond stable interrupt latency is to code for bare metal and roll your own operating system. In the attached "interrupt. tankist Posts: 5 Joined: Tue Feb 08, 2022 7:22 am. Interrupt Latency. The problem is, i have a huge latency of 200-250ms between input signal on transmitting ESP32 and receiving ESP32, and i would like to eliminate this or lower it as far as possible. ESP32 external interrupt latency. greetings sdk: IDF V4. Imagine now that we have an interrupt being fired when the signal goes low to high. I would like to know the interrupt latency for an external pin interrupt in ESP32. What is the difference between hardware interrupt and software. The following optimizations improve the execution of nearly all code, including boot times, throughput, latency, etc: Set CONFIG_ESPTOOLPY_FLASHMODE to QIO or QOUT mode (Quad I/O). For ESP32-S3, this value can be set to 80 MHz, 160 MHz, or 240 MHz. Skip to content . Arduino Interrupts Latency & Response Time. In case of interrupts, when the flags or signals are received, they notify the controller that they need to be serviced. Post by go4retro » Thu Jan 10, 2019 6:26 am . 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. Run the following command at the end of all settings. 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. MicroPython on other boards (e. Hi, I'm using a GPIO pin as a external interrupt, responding to negedge events. Post by ESP_igrr » Mon Nov 07, 2016 11:36 am . Steps to execute an interrupt in ESP32. 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 complete). CMake is an open-source, cross-platform family of tools designed to build, test and package software. Closed tannewt pushed a commit to tannewt/circuitpython that referenced this issue May 29, 2020. Improving Overall Speed. Home; Quick links. Top. This method will utilise the ESP32 memory directly inside a high-level interrupt. Only in the case where an RTOS task notification is used in place of a. Interrupt low Latency - again. External Interrupt Latency. Espressif ESP32 Official Forum. 2 posts • Page 1 of 1. Being new to this forum, let me briefly introduce myself. Alternatively, it may be enough to run the gpio_install_isr_service call on a task that is pinned to CPU1. Re: ESP IDF get GPIO level at time of interrupt. The ESP32-C3 has one core, with 31 interrupts. The cores in the ESP32 are labeled “Core 0” and “Core 1. 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. 4 (brighnes and contrast enable)+. At 17uS, the esp32 responds to the event and sets an IO line to respond, which is too late. Unlike on other micropython ports, on the ESP32 the time between a hardware interrupts occurring and Python handlers being called is irregular and. The PLIC adds another 3 cycles from an external interrupt source. I'm interested to see if the GPIO interrupt latency is more consistent than I have found on the ESP32. :49 am. An ESP32 timer group should be identified using timer_group_t. jeromeh Posts: 31 Joined: Thu Dec 22, 2016 5:41 am. At 17uS, the esp32 responds to the event and sets an IO line to respond, which is too late. 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. Each interrupt has a programmable priority level. That needs 2 µs latency to start the waiting task RTOS_2 in core 0. I can not figure out how to remove buffer or increase size to as close as possible real time transmission. RF operations of the ESP32 SoC require time-sensitive and interrupt-based software which can be complex. Apparently the expected interrupt latency is around 2 us; alternatively you can write your own high level interrupt handlers in assembler. 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. 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. 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. The right way to do this is to have the interrupt service routine just wake up a task. Post by jfmateos » Mon Nov 07, 2016 9:03 am . T2 gives us the exact number of CPU clocks between 1 PPS edges, which is an exact measure of its actual frequency. Now I have found the time to do it for myself and with the ESP32 and some other platforms. Post by edigi32 » Tue Feb 26, 2019 9:57 am . ESP32 module has a dual-core processor and each core consists of 32 interrupts. Configuring and using interrupts in MicroPython on the ESP32 A basic skeleton script. 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. This assumes that the interrupt handler is in cache or ITIM. I would like to know the interrupt latency for an external pin interrupt in ESP32. Calling a C function from an interrupt requires the CPU's context to be saved, and the call stack to be switch to that of the C ISR.