PWM waveform is not output when analogWrite() is called.

[MikiyaKobayashi]

■ Corresponding version
v.2.0.0 to v.2.3.1

■ API function affected by defect

• analogRead()
  • The analogRead() reads the value from the specified analog pin
• analogWrite()
  • The analogWrite() writes an analog value (PWM wave) to a pin
  • The first argument is the pin, and the second argument is the duty cycle

■ Contents and Occurrence conditions
Depending on the pin specified by analogRead(), an illegal write occurs to the RAM referenced by analogWrite()
As a result, PWM waveform is not output when analogWrite() is called

The conditions for this to occur are as follows:

• Call the analogRead(), then analogWrite()
• Specify a specific pin with the analogRead() and analogWrite()

The problematic combination patterns are as follows:

• Combination pattern 1

data = analogRead(A0);
analogWrite(3,128);

• Combination pattern 2

data = analogRead(A2);
analogWrite(5,128);

• Combination pattern 3

data = analogRead(A3);
analogWrite(6,128);

■ Workaround
This issue can be avoided by calling the pinMode(OUTPUT) before calling the analogWrite()
Below is the code that works around this issue

• Combination pattern 1

  data = analogRead(A0);
  pinMode(3,OUTPUT);
  analogWrite(3,128);

• Combination pattern 2

  data = analogRead(A2);
  pinMode(5,OUTPUT);
  analogWrite(5,128);

• Combination pattern 3

  data = analogRead(A3);
  pinMode(6,OUTPUT);
  analogWrite(6,128);

■ Permanent measures
Scheduled to be fixed in V2.3.2