MSP432 Serial.available() always returns "1"

[robertinant]

From @croberts15 on November 3, 2015 15:48

I am trying to interface a WiFi peripheral communicating with AT commands over UART and I am getting incorrect messages. Trying to debug shows that Serial.available() always returned 1. I tried running simple code that would just run Serial.available() on the COM window:

 while(Serial.available()){
    Serial.print("Serial.available() = ");
    Serial.println(Serial.available());
   cpuIn = Serial.read();
}

and again, Serial.available returned 1, even if I entered a long string of values. If I ran this same code on a msp4305529, the serial.available() value would max out at 15 and decrement to zero as I read off the buffer.

Copied from original issue: energia/Energia#755