os_timer_arm_us does not work truly

[etoshey]

Basic Infos

Hardware

Hardware: ESP-12 & ESP-07
Core Version: 2.3.0

Description

Hi,
I want to generate 4uS square wave with 50% duty cycle and I use os_timer_arm_us function but that generate 4mS square wave same as os_timer_arm function!!
what is my mistake? Thank you

Settings in IDE

Module: Generic ESP8266 Module
Flash Size: 4MB
CPU Frequency: 80Mhz
Flash Mode: DIO
Flash Frequency: 40Mhz?
Upload Using: SERIAL
Reset Method: ck

Sketch

#define out_pin 5
volatile unsigned long timeSpent=1;
volatile int toggle;
unsigned long prevMillis=0;
unsigned long current_time=0;

extern "C" {
#define USE_US_TIMER
#include "user_interface.h"
#include "osapi.h"
#define os_timer_arm_us(a, b, c) ets_timer_arm_new(a, b, c, 0)
}

os_timer_t t0;

void myIsrTimer(void*z)
{
// current_time = micros();
// timeSpent = current_time - prevMillis;
// prevMillis = current_time;
toggle = (toggle == 1) ? 0 : 1;
digitalWrite(out_pin,toggle);
}

void setup() {
pinMode(out_pin, OUTPUT);
os_timer_setfn(&t0, myIsrTimer, NULL);
os_timer_arm_us(&t0, 4, true);
// Initialise Serial connection
Serial.begin(115200);
}

void loop() {
// put your main code here, to run repeatedly:
//Serial.print(timeSpent);Serial.print(" ");
}

Debug Messages

[devyte]

@etoshey The referenced function is an Espressif SDK api, not an api offered by the core in this repo.
The Espressif SDK api referene for sdk 2.1.0, section 3.1.5, says the following about os_timer_arm_us():

void	os_timer_arm_us(os_timer_t *ptimer,
                                    uint32_t microseconds,
                                    bool repeat_flag)
os_timer_t *ptimer: timer structure. 
uint32_t microseconds: timing; unit: microsecond, the minimum value is 0x64, the maximum value allowed to input is 0xFFFFFFF. 
bool	repeat_flag: whether the timer will be invoked repeatedly or not. 

This is not the right place to ask such questions. This is an issue tracker, meant to track issues in the Arduino-like core libs. Please do your research, and if you need help, refer to a community forum.
Closing per #3655 .