FX809 - FFSK Modem
An intelligent, half-duplex, FFSK/MSK modem which operates under “C-BUS” control. In addition this modem provides software selectable checksum generation and error checking, in accordance with MPT1327. The FX809, using Interrupt and Status Register procedures, performs the functions described below:.
FX809 FFSK Modem Recovered Clock CHECKSUM GEN/CHECK Rx IN FFSK RECEIVER XTAL/CLOCK XTAL CLOCK GENERATOR Recovered Clock BYTE COUNTER DATA REGISTER 1 DATA REGISTER 2 Rx SYNC Detect SYNC/SYNC DETECT Rx SYNC Detect Rx FREE FORMAT CS REPLY DATA SERIAL CLOCK COMMAND DATA C-BUS INTERFACE AND CONTROL LOGIC Interrupt Enable RX DATA BUFFER TX DATA BUFFER Rx Data Ready Tx Data Ready SYNC PROGRAM LOW HIGH Tx Idle 8-Bit Parallel Bus ADDRESS DECODER Rx SYNC Detect Rx SYNC D.