undefined reference to pwm_init

[MatjazBostic]

I get this error:

Compiling 'pwmTest' for 'NodeMCU 1.0 (ESP-12E Module)'
pwmTest.cpp.o: (.text.setup+0xc): undefined reference to pwm_init(unsigned int, unsigned int*, unsigned int, unsigned int (*) [3])
pwmTest.cpp.o: (.text.setup+0x10): undefined reference to pwm_start()

pwmTest.cpp.o: In function setup
pwmTest.ino:23: undefined reference to pwm_init(unsigned int, unsigned int*, unsigned int, unsigned int (*) [3])
pwmTest.ino:24: undefined reference to pwm_start()

collect2.exe*: error: ld returned 1 exit status

Error compiling for board NodeMCU 1.0 (ESP-12E Module)

pwmTest.ino:

#include<pwm.h>

#define PWM_CHANNELS 1
const uint32_t period = 5000; // * 200ns ^= 1 kHz

                              // PWM setup
uint32 io_info[PWM_CHANNELS][3] = {
    // MUX, FUNC, PIN
    { PERIPHS_IO_MUX_MTDI_U,  FUNC_GPIO12, 12 }
};

// initial duty: all off
uint32 pwm_duty_init[PWM_CHANNELS] = { 0 };

void setup() {
    pwm_init(period, pwm_duty_init, PWM_CHANNELS, io_info);
    pwm_start();
}

void loop() {

}

I have found "core_esp8266_wiring_pwm.c" in Arduino15\packages\esp8266\hardware\esp8266\2.3.0\cores\esp8266 and replaced its contents with your code.

What am I doing wrong?

[StefanBruens]

Your makefile is incorrect. Remove any "-lpwm" statement and add "pwm.o" instead.

This is not specific to this code, please read up about makefiles and linker statements.

[MatjazBostic]

@StefanBruens Do I have to install complete esp8266 sdk to use this file? (I am using Arduino right now)