CMX867 View Datasheet(PDF) - CML Microsystems Plc
Part Name
Description
MFG CO.
'CMX867' PDF : 48 Pages View PDF
Low Power V.22 Modem
CMX867
Tx Mode Register b7-5: DTMF Twist (DTMF mode)
These 3 bits allow for adjustment of the DTMF twist to compensate for the frequency
response of different external circuits. Set b8 to 0. The device varies the twist by making
changes to the upper tone group levels. Note that the twist cannot be adjusted mid-tone.
b7
b6
b5
0
0
0
+2.0dB twist (normal setting when external response is flat)
0
0
1
+1.0dB twist
0
1
0
+1.5dB twist
0
1
1
+2.5dB twist
1
0
0
+3.0dB twist
1
0
1
+3.5dB twist
1
1
0
+4.0dB twist
1
1
1
+4.5dB twist (do not use in conjunction with the 0dB tx level
setting).
Tx Mode Register b6-5: Tx Scrambler (DPSK modes)
These 2 bits control the operation of the Tx scrambler used in DPSK modes. Set both
bits to 0 in FSK modes.
b6
b5
1
1
Scrambler enabled, 64 ones detect circuit enabled (normal use)
1
0
Scrambler enabled, 64 ones detect circuit disabled
0
x
Scrambler disabled
Tx Mode Register b4-3: Tx Data Format (DPSK and FSK modes)
These two bits select Synchronous or Start-stop mode and the addition of a parity bit to
transmitted characters in Start-stop mode.
b4
b3
1
1
Synchronous mode
1
0
Start-stop mode, no parity
0
1
Start-stop mode, even parity bit added to data bits
0
0
Start-stop mode, odd parity bit added to data bits
Tx Mode Register b2-0: Tx Data and Stop bits (DPSK and FSK: Start-Stop modes)
In Start-stop mode these three bits select the number of Tx data and stop bits.
b2 b1 b0
1
1
1 8 data bits, 2 stop bits
1
1
0 8 data bits, 1 stop bit
1
0
1 7 data bits, 2 stop bits
1
0
0 7 data bits, 1 stop bit
0
1
1 6 data bits, 2 stop bits
0
1
0 6 data bits, 1 stop bit
0
0
1 5 data bits, 2 stop bits
0
0
0 5 data bits, 1 stop bit
© 2004 Consumer Microcircuits Limited
23
D/867/5
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