CMX878D1 View Datasheet(PDF) - CML Microsystems Plc
Part Name
Description
MFG CO.
'CMX878D1' PDF : 63 Pages View PDF
Line Powered Modem plus DAA
CMX878
1.5.12.8 General Control Register
General Control Register: 16-bit write-only. C-BUS address $E0
This register controls general features of the MODEM & TONES PROCESSOR block such as the
Powersave and Loopback modes, and the IRQ mask bits. It also allows the fixed compromise equalisers
in the Tx and Rx signal paths to be disabled if desired, and sets the internal clock dividers to use either a
11.0592 or a 12.288 MHz XTAL frequency.
All bits of this register are cleared to 0 by a General Reset command.
Bit: 15 14 13 12 11 10 9
8
7
6
5
4
3
2
1
0
0
0
0 Xtal LB Equ 0 Pwr Rst Irqn
freq
en
IRQ Mask Bits
General Control Register b15-13: Reserved, set to 000
General Control Register b12: Xtal frequency
This bit should be set according to the Xtal frequency.
b12 = 1
b12 = 0
11.0592MHz
12.2880MHz
General Control Register b11: Analogue Loopback test mode
This bit controls the analogue loopback test mode. Note that in loopback test mode both
Transmit and Receive Mode Registers should be set to the same modem type and band or bit
rate.
b11 = 1
b11 = 0
Local analogue loopback mode enabled
No loopback (normal modem operation)
General Control Register b10: Tx and Rx Fixed Compromise Equalisers
This bit allows the Tx and Rx fixed compromise equalisers in the modem transmit and receive
filter blocks to be disabled.
b10 = 1
b10 = 0
Disable equalisers
Enable equalisers (600, 1200 or 2400bps modem modes)
General Control Register b9: Reserved, set to 0
© 2002 Consumer Microcircuits Limited
33
D/878/2
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