Sub-Audio Signaling Processor
Page 2 of 24
MX805A
Contents
Section
Page
1 Block Diagram ............................................................................................................... 4
2 Signal List ...................................................................................................................... 5
3 External Components ................................................................................................... 7
3.1
Input configurations............................................................................................................ 8
3.1.1
Using and External Op-Amp...................................................................................................... 8
4 General Description ...................................................................................................... 9
4.1
4.2
Glossary ............................................................................................................................ 9
Operating Modes ............................................................................................................... 9
4.2.1
4.2.2
4.2.3
4.2.4
NRZ Encoding ........................................................................................................................... 9
CTCSS Encoding ...................................................................................................................... 9
NRZ Decoding ......................................................................................................................... 10
CTCSS Decoding .................................................................................................................... 10
5 Controlling Protocol ................................................................................................... 10
5.1
MX805A Internal Registers .............................................................................................. 10
5.1.1
5.1.2
5.1.3
5.1.4
5.1.5
5.1.6
5.1.7
Control Register (70H/78H)..................................................................................................... 10
Status Register (71H/79H) ...................................................................................................... 10
CTCSS Rx Frequency Register (72H/7AH) ............................................................................ 10
CTCSS Tx Frequency/NRZ Tx or Rx Baud Rate Register (73H/7BH) ................................... 10
NRZ Rx Data Register (74H/7CH) .......................................................................................... 10
NRZ Tx Data Register (75H/7DH)........................................................................................... 10
Gain Set Register (76H/7EH) .................................................................................................. 10
Write to Control Register - A/C 70H (78H) followed by 1 byte of Command Data.................. 12
General Reset ......................................................................................................................... 12
Read Status Register –A/C 71H (79H) followed by 1 byte of Rely Data. ............................... 13
Read CTCSS RX Frequency Register –A/C 72H (7AH) followed by 2 bytes of Reply Data .. 13
Write to CTCSS TX Frequency/NRZ Baud Data Rate Register –A/C 73H (7BH) followed
by 2 bytes of Command Data.................................................................................................. 15
Read NRZ RX Data Register – A/C 74H (7CH) followed by 1 byte Reply Data ..................... 17
Write to NRZ TX Data Register – A/C 75H (7DH) followed by 1 byte of Command Data. ..... 17
Write to Gain Set Register – A/C 76H (7EH) followed by 1 byte of Command Data .............. 17
5.2
Address/Commands ........................................................................................................ 11
5.2.1
5.2.2
5.2.3
5.2.4
5.2.5
5.2.6
5.2.7
5.2.8
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2001 MX-COM, Inc.
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA
www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054
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Doc. # 20480116.005
CMLMICRO [ CML MICROCIRCUITS ]
