DB929B datasheet(21/51 Pages) CMLMICRO

21 / 51 page

4-Level FSK Modem Data Pump

Page 21 of 50

MX929B PRELIMINARY INFORMATION

www.mxcom.com Tel: 800 638 5577 336 744 5050

Fax: 336 744 5054

Doc. # 20480171.003

4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA

All trademarks and service marks are held by their respective companies.

4.5.2.14 T24S: Transmit 24 Symbols

This task, which is intended to facilitate the transmission of Symbol and Frame Sync patterns as well as

special test sequences, takes 6 bytes of data from the Data Block Buffer and transmits them as 24 4-level

symbols without any CRC, FEC, interleaving, or adding any 'S' symbols.

Byte 0 of the Data Block Buffer is sent first, byte 5 last.

Once the modem has read the data bytes from the Data Block Buffer, the BFREE and IRQ bits of the Status

the modem.

The tables below show what data needs to be written to the Data Block Buffer to transmit the MX929B Symbol

and Frame Sync sequences:

'Symbol Sync'

Values written to Data Block Buffer

Symbols

Binary

Hex

-3

Byte 0:

11110101

-3

Byte 1:

11110101

-3

Byte 2:

11110101

-3

Byte 3:

11110101

-3

Byte 4:

11110101

-3

Byte 5:

01011111

'Frame Sync'

Values written to Data Block Buffer

Symbols

Binary

Hex

-1

Byte 0:

00100010

-1

-3

Byte 1:

00110111

-3

-1

-3

Byte 2:

01001001

-1

Byte 3:

11110010

-3

Byte 4:

01011011

-1

-3

Byte 5:

00011011

4.5.2.15 THB: Transmit Header Block

This task takes 10 bytes of data (Address and Control) from the Data Block Buffer, calculates and appends

the 2-byte CRC1 checksum, translates the result to 4-level symbols (with FEC), interleaves the symbols, and

transmits the result as a formatted 'Header' Block, inserting 'S' symbols at 22 symbol intervals.

Once the modem has read the data bytes from the Data Block Buffer, the BFREE and IRQ bits of the Status

4.5.2.16 TIB: Transmit Intermediate Block

This task takes 12 bytes of data from the Data Block Buffer, updates the 4-byte CRC2 checksum for inclusion

in the 'Last' block, translates the 12 data bytes to 4-level symbols (with FEC), interleaves the symbols, and

transmits the result as a formatted 'Intermediate' Block, inserting 'S' symbols at 22-symbol intervals.

Once the modem has read the data bytes from the Data Block Buffer, the BFREE and IRQ bits of the Status

4.5.2.17 TLB: Transmit Last Block

This task takes 8 bytes of data from the Data Block Buffer, updates and appends the 4-byte CRC2 checksum,

translates the resulting 12 bytes to 4-level symbols (with FEC), interleaves the symbols, and transmits the

result as a formatted 'Last' Block, inserting 'S' symbols at 22-symbol intervals.

Once the modem has read the data bytes from the Data Block Buffer, the BFREE and IRQ bits of the Status

4.5.2.18 T4S: Transmit 4 Symbols

This task is similar to T24S but takes only one byte from the Data Block Buffer, transmitting it as four 4-level

symbols.

DB929B Datasheet(PDF) 21 Page - CML Microcircuits

DB929B Datasheet(HTML) 21 Page - CML Microcircuits

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51

Datasheet Download

Link URL