Receiving Interrupts from UARTB but reading the Interrupt Identification Register reports No Interrupt Pending. Reading the RHR appears to cause the interrupt to go away. UARTB has TXB connected to a maxim line driver/isolator. The RXB line is floating. If noise or controlled signals are put on the line INTB will assert even though all of the interrupts in the Interrupt Enable register are set to zero with the exception of the THR register interrupt. When the Interrupt Identification register is read the register reports a 1 in the interrupt status bit and all zeros in the interrupt priority bits. Reading from the RHR will clear the interrupt but the interrupt will continue to come in as long as there is noise or a controlled toggling signal on the line. A read from the Line Status Register indicates that there is data in the receiver and depending on the frequency of the signal being applied to the RXB pin and what baud rate the UART is configured to dictates if any of the error bits are set.
