HD64570 Datasheet, PDF (151/469 Pages) Hitachi Semiconductor – Serial Communications Adaptor

RXRDY = 1: Indicates that the data byte count in the receive buffer is equal to or greater than
RXF + 1, or that at least one byte of data still remains in the receive buffer after the data byte
count in the receive buffer is temporarily equal to or greater than RXF + 1. In bit synchronous
mode, this bit also indicates that one or more bytes of EOM data are in the receive buffer.
Rev. 0, 07/98, page 135 of 453