Delay() With Small Values (eg Delay(1)) Does Not Delay If System HZ ...

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Additional navigation options delay() with small values (e.g. delay(5)) does not delay if system HZ (CONFIG_FREERTOS_HZ) <1000 #6946New issueNew issueClosedCloseddelay() with small values (e.g. delay(5)) does not delay if system HZ (CONFIG_FREERTOS_HZ) <1000#6946@egnor

Description

@egnoregnoropened on Jul 5, 2022

Board

OLIMEX ESP32-POE (but will happen anywhere I think)

Device Description

Stock OLIMEX ESP32-POE, but I believe this will happen on any board

Hardware Configuration

Nothing attached

Version

latest development Release Candidate (RC-X)

IDE Name

PlatformIO

Operating System

Ubuntu 22.04

Flash frequency

40MHz

PSRAM enabled

yes

Upload speed

115200

Description

The Arduino delay() function is implemented as follows:

arduino-esp32/cores/esp32/esp32-hal-misc.c

Line 178 in fcd4799

vTaskDelay(ms / portTICK_PERIOD_MS);

If portTICK_PERIOD_MS > 1 (i.e. CONFIG_FREERTOS_HZ < 1000), then small values will round down to 0, and no delay will happen. I'm not super familiar with the delay facilities in FreeRTOS / ESP-IDF but there has to be some way to do a shorter delay (busy-wait, if nothing else)?

See also: platformio/platform-espressif32#846

Sketch

// Run me with CONFIG_FREERTOS_HZ=100 to see the problem void setup() { Serial.begin(115200); } void loop() { Serial.printf("BEFORE msec=%lu\n", millis()); for (int i = 0; i < 20; ++i) delay(5); Serial.printf("AFTER msec=%lu\n\n", millis()); }

Debug Message

(none)

Other Steps to Reproduce

No response

I have checked existing issues, online documentation and the Troubleshooting Guide

  • I confirm I have checked existing issues, online documentation and Troubleshooting guide.

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Tag » Arduino Delay Hz