CMX808AE3 CML Microcircuits, CMX808AE3 Datasheet - Page 11

• Manufacturer Part Number: CMX808AE3
• Description: Family Radio CTCSS Type 2 Encoder and Decoder
• Manufacturer: CML Microcircuits

Family Radio CTCSS 'Type 2' Encoder and Decoder
TONE CLONING Register (Hex address $9C)
This register enables and disables tone cloning as shown below:
Figure 4 shows the tone cloning routine.
8-bit Read Only Registers
Read Only Register Description
SUB-AUDIO STATUS Register (Hex address $81)
Reading the SUB-AUDIO STATUS register clears the interrupt (IRQN).
This register is used to indicate the status of the device as described below:
(Bits 7, 6, 5 and 4)
TONE DECODE
(Bit 3)
CTCSS RX TONE
(Bits 2, 1 and 0)
COMMAND
ADDRESS/
1999 Consumer Microcircuits Limited
HEX
$81
$9C = $01 enables tone cloning.
$9C = $00 disables tone cloning.
SUB-AUDIO
REGISTER
STATUS
NAME
Reserved for future use. These will be set to "0" but should be ignored by user's
software.
This bit indicates the status of the tone decoder. A "1" indicates a tone has
been detected (TONE DECODE) and a "0" indicates the loss of the tone
(NOTONE).
TONE DECODE means that a tone has been decoded and its characteristics
are defined by the bandwidth (see SUB-AUDIO CONTROL register $80, Bits 5,
4, 3 and 2) and the CTCSS RX TONE number (see SUB-AUDIO STATUS
register $81, Bits 2, 1 and 0).
When Bit 6 in the SUB-AUDIO CONTROL register $80 is set to "0" the TONE
DECODE Bit 3 will be set to "0".
Identification of a valid tone which is not in the pre-programmed list of up to 7
tones will cause the decoder to move to the TONE DECODE state with the RX
TONE address of "111" in Bits 2, 1 and 0; indicating a valid but unrecognised
tone. Loss of tone will cause the NOTONE timer to be started. If loss of tone
continues for the duration of the time-out period, then the decoder will move to
NOTONE state and the identification of pre-programmed tones will start again.
The time-out period is not user adjustable.
These three bits hold a Hex number. Numbers $0 to $6 represent the address
of the CTCSS tone decoded according to the tones programmed in the CTCSS
RX PROGRAM register $84.
any tone that is not described by CTCSS DECODER BANDWIDTH (Bits 5, 4, 3
and 2 in the SUB-AUDIO CONTROL register $80) and CTCSS FREQUENCY
(Bits 11 to 0 in the CTCSS RX PROGRAM register $84).
BIT 7
(D7)
0
BIT 6
(D6)
0
BIT 5
(D5)
0
11
BIT 4
(D4)
0
The Hex number $7 indicates the presence of
DECODE
TONE
BIT 3
(D3)
BIT 2
BIT 2
MSB
(D2)
CTCSS RX TONE
BIT 1
BIT 1
(D1)
BIT 0
BIT 0
(D0)
LSB
CMX808A
D/808A/5