CMX808AE3 CML Microcircuits, CMX808AE3 Datasheet - Page 8

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

Family Radio CTCSS 'Type 2' Encoder and Decoder
Write Only Register Description
GENERAL RESET (Hex address $01)
The reset command has no data attached to it. It sets the device registers to zero (all powersaved) with the
exception of Bits 2, 1 and 0 of the SUB-AUDIO STATUS register $81.
SUB-AUDIO CONTROL Register (Hex address $80)
This register is used to control the functions of the device as described below:
CTCSS TX ENABLE
and DECODER
ENABLE
(Bits 7 and 6)
CTCSS DECODER
BANDWIDTH
(Bits 5, 4, 3 and 2)
(Bit 1)
CTCSS IRQ MASK
(Bit 0)
AUDIO CONTROL Register (Hex address $82)
This register is used to control the functions of the device as described below:
Note: TX BPF ENABLE (Bit 7) and RX BPF ENABLE (Bit 6) should not be enabled at the same time.
TX BPF ENABLE
(Bit 7)
1999 Consumer Microcircuits Limited
These two bits enable and disable the CTCSS decoder (Rx) or transmitter (Tx)
according to the table below:
These four bits set the bandwidth of the CTCSS tone decoder according to the
table below:
Reserved for future use. This bit should be set to "0".
When this bit is set to "1" it enables the interrupt.
When this bit is set to "0" the interrupt is masked.
When this bit is "1" the audio band-pass filter is enabled and the output of the
filter is switched to TX AUDIO OUT. The output is then controlled by BPF UN-
MUTE. See Bit 5 below.
When this bit is “0” the audio band pass filter is disabled (powersaved) and the
output of the filter is disconnected from TX AUDIO OUT, which is then in a high
impedance state.
Bit
Bit
Tx
5
1
1
1
1
1
1
1
1
7
0
0
1
1
Bit 6
Bit
Rx
4
0
0
0
0
1
1
1
1
0
1
0
1
Tx disabled, Rx disabled
Tx disabled, Rx enabled
Tx enabled, Rx disabled
Tx enabled, Rx enabled
Bit
3
0
0
1
1
0
0
1
1
Bit
Function
2
0
1
0
1
0
1
0
1
8
Decode
±1.1%
±1.3%
±1.6%
±1.8%
±2.0%
±2.2%
±2.5%
±2.7%
Will
BANDWIDTH
Will Not
Decode
±2.4%
±2.7%
±2.9%
±3.2%
±3.5%
±3.7%
±4.0%
±4.2%
CMX808A
D/808A/5