CMX867D2 CML Microcircuits, CMX867D2 Datasheet - Page 19

• Manufacturer Part Number: CMX867D2
• Description: Low power V.22 modem
• Manufacturer: CML Microcircuits

Low Power V.22 Modem
1.5.10.2
General Control Register: 16-bit write-only. C-BUS address $E0
This register controls general features of the CMX867 such as the Powersave and Loopback modes, the
IRQ mask bits and the Relay Drive output. 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.
2001 Consumer Microcircuits Limited
Bit:
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.
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.
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.
General Control Register b9: Relay Drive
This bit directly controls the RDRVN output pin.
15
0
General Control Register
14
0
b12 = 1
b12 = 0
b11 = 1
b11 = 0
b10 = 1
b10 = 0
b9 = 1
b9 = 0
13
0
Xtal
freq
12
11
LB
11.0592MHz
12.2880MHz
Local analogue loopback mode enabled
No loopback (normal modem operation)
Disable equalisers
Enable equalisers (600 or 1200bps modem modes)
RDRVN output pin pulled to V
RDRVN output pin pulled to V
Equ
10
Rly
drv
9
Pwr
8
19
Rst
7
Irqn
en
6
SS
DD
5
4
IRQ Mask Bits
3
2
1
0
CMX867
D/867/2