Communication terminal increasing effective data rate on asynchronous transmission and a data transmission method therefor

Abstract

A UART sets a predetermined threshold remaining data amount n, which defines an interrupt position, in a transmission trigger detector before data transmission is completed, checks if a trigger, which indicates the value of a read pointer RP or a count value N has reached a position indicated by the setting, has occurred and, if the trigger has occurred, causes a trigger detector to output a interrupt output control signal to an internal interrupt circuit to perform internal interrupt processing. Upon detecting this trigger, the internal interrupt circuit outputs an internal interrupt signal. When all data has not yet been transmitted from a transmission FIFO circuit, a CPU of a host controls the amount of data to be transferred to the transmission FIFO circuit, considering the threshold n, to prevent data in that circuit from being overwritten.