Asynchronous Receiver State Machine Variables
DSR/ - Data Set Ready
- Low when a 8 bit word has been received and is ready to be read
EMPTY - Buffer Empty
- High when RX buffer is empty and ready for contents of shift register
FR/ - Frame Error
- Low when the stop bit was not correct
OF/ - Overflow
- Low if first byte has not been read by CPU, a second byte is held in the shift register, and a third has begun reception, third word is ignored.
- STOP - Stop Bit
- Contents of cell 9 in the receive shift register, Low when a full word has been received correctly
RX - Receive bit
- Output of differential receiver