CMX878D6 View Datasheet(PDF) - CML Microsystems Plc
Part Name
Description
MFG CO.
'CMX878D6' PDF : 63 Pages View PDF
Line Powered Modem plus DAA
CMX878
General Control Register b8: Powerup
This bit controls the internal power supply to most of the internal circuits, including the Xtal
oscillator, VBIAS supply and the MODEM & TONES PROCESSOR block. It does not affect the
DAC and ADC. It does not affect the circuits which run off the Standby Supply.
Note that the General Reset command clears this bit, putting the MODEM & TONES
PROCESSOR block into Powersave mode.
When the device is switched from Powersave mode to normal operation by setting the
Powerup bit to 1, the Reset bit should also be set to 1 and should be held at 1 for about 20ms
while the internal circuits, Xtal oscillator and VBIAS stabilise before starting to use the
transmitter or receiver.
Changing the Powerup bit from 0 to 1 clears all bits of the Transmit Mode and Receive Mode
Registers and clears b15 and b13-0 of the Status Register.
b8 = 1
b8 = 0
MODEM & TONES PROCESSOR BLOCK powered up normally
MODEM & TONES PROCESSOR BLOCK Powersave
General Control Register b7: Reset
Setting this bit to 1 resets the CMX878’s internal circuitry, clearing all bits of the Transmit and
Receive Mode Registers and b13-0 of the Status Register.
b7 = 1
b7 = 0
Internal circuitry in a reset condition.
Normal operation
General Control Register b6: IRQNEN (IRQN O/P Enable)
Setting this bit to 1 enables the IRQN output pin.
b6 = 1
b6 = 0
IRQN pin driven low (to VSS) if the IRQ bit of the Status Register = 1
IRQN pin disabled (high impedance)
General Control Register b5-0: IRQ Mask bits
These bits affect the operation of the IRQ bit of the Status Register as described in section
1.5.12.13.
© 2002 Consumer Microcircuits Limited
34
D/878/2
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