Data Sheet
4-Level FSK Modem Data Pump Page 2 of 47 MX919B PRELIMINARY INFORMATION
©2001 MX•COM, INC. www.mxcom.com Tele: 800 638 5577 336 744 5050 Fax: 336 744 5054 Doc. # 20480170.003
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CONTENTS
Section Page
1. Block Diagram ............................................................................................................... 6
2. Signal List ...................................................................................................................... 7
3. External Components ................................................................................................... 8
4. General Description ...................................................................................................... 9
4.1 Description of Blocks ......................................................................................................... 9
4.1.1 Data Bus Buffers..................................................................................................................... 9
4.1.2 Address and R/W Decode ...................................................................................................... 9
4.1.3 Status and Data Quality Registers.......................................................................................... 9
4.1.4 Command, Mode, and Control Registers ............................................................................... 9
4.1.5 Data Buffer.............................................................................................................................. 9
4.1.6 CRC Generator/Checker ........................................................................................................ 9
4.1.7 FEC Generator/Checker ......................................................................................................... 9
4.1.8 Interleave/De-Interleave Buffer............................................................................................... 9
4.1.9 Frame Sync Detect ................................................................................................................. 9
4.1.10 Rx Input Amp ........................................................................................................................ 10
4.1.11 RRC Low Pass Filter ............................................................................................................ 10
4.1.12 Tx Output Buffer.................................................................................................................... 11
4.1.13 Rx Level/Clock Extraction..................................................................................................... 12
4.1.14 Clock Oscillator and Dividers................................................................................................ 12
4.2 Modem - µC Interaction ................................................................................................... 12
4.3 Binary to Symbol Translation ........................................................................................... 13
4.4 Frame Structure............................................................................................................... 14
4.5 The Programmer’s View................................................................................................... 15
4.5.1 Data Block Buffer.................................................................................................................. 15
4.5.2 Command Register ............................................................................................................... 15
4.5.2.1 Command Register B7: AQSC - Acquire Symbol Clock ................................................ 16
4.5.2.2 Command Register B6: AQLEV - Acquire Receive Signal Levels ................................. 16
4.5.2.3 Command Register B5: CRC ........................................................................................ 16
4.5.2.4 Command Register B4: TXIMP - Tx Level/Impulse Shape ............................................ 16
4.5.2.5 Command Register B3 - Reserved ................................................................................ 16
4.5.2.6 Command Register B2, B1, B0: TASK........................................................................... 16
4.5.2.7 NULL: No effect .............................................................................................................. 18
4.5.2.8 SFSH: Search for Frame Sync plus Header Block ........................................................ 18
4.5.2.9 RHB: Read Header Block............................................................................................... 18
4.5.2.10 RILB: Read 'Intermediate' or 'Last' Block ....................................................................... 18
4.5.2.11 SFS: Search for Frame Sync ......................................................................................... 18
4.5.2.12 R4S: Read 4 Symbols .................................................................................................... 19
4.5.2.13 T24S: Transmit 24 Symbols ........................................................................................... 19
4.5.2.14 THB: Transmit Header Block.......................................................................................... 19
4.5.2.15 TIB: Transmit Intermediate Block ................................................................................... 20
4.5.2.16 TLB: Transmit Last Block ............................................................................................... 20