FX919A Datasheet, PDF (30/44 Pages) CML Microcircuits – 4-Level FSK Modem Data Pump

4-Level FSK Modem Data Pump
FX919A
Figures 15a and 15b illustrate the host µC routines needed to send a single Frame consisting of Symbol and
Frame Sync patterns, a Header block, any number of Intermediate blocks and one Last block. It is assumed
that the Tx Interrupt Service Routine (Figure 15b) is called whenever the FX919A's IRQN output line goes low.
Figure 15a Transmit Frame Example Flowchart, Main Program
Note that the RESET command in Figure 15a and the practice of disabling the FX919A's IRQN output when not
needed are not essential but can eliminate problems during debugging and if errors occur in operation.
Note also that the CRC bit should be set appropriately whenever a byte is written to the Command Register.
© 1996 Consumer Microcircuits Limited
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D/919A/4