analogWrite is not implemented in the Arduino environment. There is a much better set of PWM controllers available. The code below demonstrates how to get PWM output on a pin.
// Code for PWM drive of a small motor
// ESP32 does not support analogWrite but has ledcWrite instead
// There are 16 PWM channels numbered 0-15
// Resulotion is programmable. I tested 5-12 bits
// Frequency is programmable. I tested 1kHz to 100kHz, all accurate
// This code is placed in the public domain
#define MotorPin 23
#define pwmCh 0
#define pwmResolution 8 // 8 bit resolution
#define pwmFrequency 10000
void setup() {
// Choose the pwm controller to use on the IO-pin
ledcAttachPin(MotorPin, pwmCh);
// Set the frequency and resolution
ledcSetup(pwmCh, pwmFrequency, pwmResolution); // 10 kHz PWM, 8-bit resolution
// Set the duty cycle
ledcWrite(pwmCh, 127);
}
uint8_t dutyCycle = 12 ;
void loop() {
// increase the duty cycle every 20ms
ledcWrite(pwmCh, dutyCycle++ );
delay( 20 );
}