Baseband Processor For Mixed Mode Land Mobile Radio
CMX880
$CC SUB-AUDIO AND SELCALL STATUS: 16-bit read-only
15
14
13
12
11
10
9
8
0
Bit:
Listed
Selcall
tone
0
0
Unlisted
Selcall
tone
Detected Selcall Tone Frequency
present
present
7
6
5
4
3
2
1
Bit:
Listed
CTCSS
tone
DCS Code
present
DCS
Inverted
Unlisted
Sub-Audio
Tone
Detected CTCSS Tone Frequency
present
present
This word holds the current status of the CMX880 sub-audio and Selcall sections. This word should be read by
the host, following an interrupt caused by a sub-audio or Selcall event.
If bit 15 = 1 a Listed (pre-programmed) Selcall tone has been detected. The detected Selcall frequency is
indicated by the content of bits 8 to 11. The value in bits 8 to 11, ‘Detected Selcall Tone Frequency’, identifies
the frequency by its position in the Selcall tone table (see ‘PROGRAMMING REGISTER’, address $C8). If bit 15
= 0 there is no Selcall tone being detected. A change in the state of bit 15 will cause bit 6 of the ‘STATUS’
register ($C6), ‘Selcall State Change’, to be set to 1.
If a Selcall tone is detected but is not in the Selcall Tone table, bit 12 will be set to 1; zero otherwise. A change
in the state of bit 12 will cause the ‘CTCSSS State Change’ bit (bit 6) of the ‘STATUS’ register ($C6) to be set to
1.
If bit 7 = 1 a Listed (pre-programmed) CTCSS tone has been detected. The detected CTCSS frequency is
indicated by the content of bits 0 to 3. The value in bits 0 to 3, ‘Detected CTCSS Tone Frequency’, identifies the
frequency by its position in the CTCSS tone table (see ‘PROGRAMMING REGISTER’, address $C8). If bit 7 = 0
there is no CTCSS tone being detected. A change in the state of bit 7 will cause bit 9 of the ‘STATUS’ register
($C6), ‘CTCSS State Change’, to be set to 1.
If a CTCSS tone is detected in the sub-audio range, but is not in the CTCSS Tone table, bit 4 will be set to 1;
zero otherwise. A change in the state of bit 4 will cause bit 9 of the ‘STATUS’ register ($C6), ‘CTCSS State
Change’, to be set to 1.
If bit 6 = 1 the DCS code has been detected. If bit 6 = 0 there is no DCS code being detected. A change in the
state of bit 6 will cause bit 8 of the ‘STATUS’ register ($C6), ‘DCS State Change’, to be set to 1. Bit 5 indicates
whether the DCS code was detected as ‘True’ or ‘Inverse’ coding. If bit 5 is 0, the coding is ‘True’,
corresponding to +ve frequency deviation representing a 1 and -ve frequency deviation representing a 0 in the
RF band. If bit 5 is 1, the coding is ‘Inverse’, corresponding to -ve frequency deviation representing a 1 and +ve
frequency deviation representing a 0 in the RF band. This bit is only applicable if bit 6 = 1.
ã 2001 Consumer Microcircuits Limited
51
D/880/1
CMLMICRO [ CML MICROCIRCUITS ]
