CMX969 Consumer Microcircuits Limited, CMX969 Datasheet - Page 19

• Manufacturer Part Number: CMX969
• Description: RD-LAP/MDC4800/Motient/ARDIS4-Level FSK Packet Data Modem
• Manufacturer: Consumer Microcircuits Limited

RD-LAP/MDC4800 Motient/ARDIS
CMX969
Once the modem has read the data bytes from the Data Block Buffer, the BFREE and IRQ bits of the Status
Register will be set to '1'.
T4S: Transmit 4 Symbols (RD-LAP only)
This task is similar to T24S but takes only one byte from the Data Block Buffer, transmitting it as four 4-level
symbols most significant bit first.
T8B: Transmit 8 Bits (MDC only)
This task is similar to T40B but takes only one byte from the Data Block Buffer, transmitting it as 8 bits.
TSID: Transmit Station ID (RD-LAP only)
This task takes 3 ID bytes from the Data Block Buffer, calculates and appends the 6-bit CRC0 checksum,
translates the result to 4-level symbols (with FEC) and transmits the resulting 22 symbols preceded and
followed by 'S' symbols.
Once the modem has read the data bytes from the Data Block Buffer, the BFREE and IRQ bits of the Status
Register will be set to '1'.
RESET: Stop any current action
This 'task' takes effect immediately, and terminates any current task the modem may be performing and sets
the BFREE bit of the Status Register to '1', without setting the IRQ bit. It should be used (after a delay to allow
the Xtal oscillator to start up) when V DD is applied or the ZP bit of the Mode Register changed from ‘1’ to ‘0’ to
set the modem into a known state.
Note that due to delays in the transmit low pass filter, it will take several symbol times for any change to
appear at the TXOP pin.
2001 Consumer Microcircuits Limited
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