Low Power V.32 bis Modem
CMX869
Every time the contents of the C-BUS Tx Data Register have been transferred to the Tx Data Buffer the Tx
Data Ready flag bit of the Status Register is set to 1 to indicate that new data should be loaded into the C-
BUS Tx Data Register. This flag bit will be cleared to 0 when a new value is loaded into the Tx Data
Register.
If a new value is not loaded into the Tx Data Register in time for the next Tx Data Register to Tx Data
Buffer transfer then the Status Register Tx Data Underflow bit will be set to 1. After a new value is loaded
into the Tx Data Register, the Tx Data Underflow bit should be tested to ensure that it has cleared to 0.
The new data value should be sent again if the bit remains at 1.
In Synchronous Data mode the last transmitted byte will be re-transmitted if there is no new data in the
Transmit Data Register. In Start-Stop mode a continuous Stop signal (1) will be transmitted.
The QAM (V.32bis/V.32/V.22bis/V.22) modulators include compatible data scrambler functions that are
automatically enabled as required.
© 2004 CML Microsystems Plc
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CMLMICRO [ CML MICROCIRCUITS ]
