Baseband Processor For Mixed Mode Land Mobile Radio
CMX880
$CD DTMF TX AND TONE LEVEL: 16-bit write-only
Bit:
15
14
13
12
11
10
9
8
7
6
5
0
4
3
2
1
0
Tone Level (range 0 to 255)
HI
LO
2dB
TonePair
Bit 7 (HI)
Bit 6 (LO)
0
1
Disable transmit High Tone
Enable transmit High Tone
0
1
Disable transmit Low Tone
Enable transmit Low Tone
Key Pad
Bit 3
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
Bit 2
Bit 1
Bit 0
Position
Low Tone
697Hz
697Hz
697Hz
770Hz
770Hz
770Hz
852Hz
852Hz
852Hz
941Hz
941Hz
941Hz
697Hz
770Hz
852Hz
941Hz
High Tone
1209Hz
1336Hz
1477Hz
1209Hz
1336Hz
1477Hz
1209Hz
1336Hz
1477Hz
1336Hz
1209Hz
1477Hz
1633Hz
1633Hz
1633Hz
1633Hz
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
2
3
4
5
6
7
8
9
0
*
#
A
B
C
D
Bit 4 enables twist between the high and low tone groups. If Bit 4, the 2dB control bit, is set to ‘0’, the High and
Low Tone levels are set to the same level. If Bit 4 is set to ‘1’, the Low Tone level is set to -2dB below the High
Tone level.
The ‘Tone Level’ bits 15 (MSB) to 8 (LSB) set the ‘non-voice’ in-band analogue levels (DTMF High Tone; Selcall
tone and FFSK/MSK) with a resolution of VDD/512 (1.94mV at VDD(A)=5V) per LSB.
$C3 TX DATA: 16-bit write-only
15
14
13
12
MS Data Byte
Bit 4 Bit 3
11
10
9
8
7
6
5
4
3
2
1
0
Bit:
FFSK/MSK
LS Data Byte
Bit 4 Bit 3
Bit 7
Bit 6
Bit 5
Bit 2
Bit 1
Bit 0
Bit 7
Bit 6
Bit 5
Bit 2
Bit 1
Bit 0
C4FM/
CQPSK
Symbol 7
Bit 1 Bit 0
Symbol 6
Bit 1 Bit 0
Symbol 5
Bit 1 Bit 0
2’s complement encoded voice data
Symbol 4
Symbol 3
Symbol 2
Symbol 1
Bit 1 Bit 0
Symbol 0
Bit 1 Bit 0
Bit 1 Bit 0
Bit 1 Bit 0
Bit 1 Bit 0
VOICE
This word holds either the next 2 bytes of FFSK/MSK data, the next 8 C4FM/CQPSK symbols or the next Voice
level data to be transmitted. Outgoing data is treated as continuous. If new data is not provided before the
current data has been transmitted, the current data will be re-transmitted, until new data is provided.
Transmission of the current word of data will be completed before transmission of the new data begins.
The most significant bit of FFSK/MSK data is transmitted first. The most significant symbol of C4FM/CQPSK
data is transmitted first. Bits or symbols beyond the actual data message length should be padded with
innocuous values (system dependent). In the C4FM case an innocuous symbol sequence may be “+3, +3, -3, -
ã 2001 Consumer Microcircuits Limited
47
D/880/1
CMLMICRO [ CML MICROCIRCUITS ]
