T9000
Preliminary Data Sheet
November 2000
ISDN Network Termination Node (NTN) Device
13 dc/dc Control Generator
This module generates a square wave signal (50% duty cycle) with a programmable period. The output frequency
is controlled by register DCCF and ranges from 15 kHz to 480 kHz. It can be expressed by:
Fdc/dc = 960/(2 * (DCV + 1)) kHz.
As an example, DCV = 14 generates a 32 kHz square wave output signal.
This module can be disabled by setting DCCF[DC_E] to 0.
The output of this module, SYNCO, is available on pin GPIO2.3 when GPAF1[GPAF2.3] is set. If GPAF1[GPAF2.3]
= 0, it is recommended that the dc/dc module be disabled to minimize power consumption (see DC_E bit in DCR0
register).
13.1 dc/dc Control Generator Register Set
Table 111. DCCF: dc/dc Configuration Register (0x4B)
Reg
R/W
Bit 7
—
Bit 6
—
Bit 5
DC_E
0
Bit 4
DCV4
—
Bit 3
DCV3
—
Bit 2
DCV2
—
Bit 1
DCV1
—
Bit 0
DCV0
—
DCCF
R/W
RESET Default
0
0
Bit #
7—6
5
Symbol
—
Name/Description
Reserved. Program to 0.
DC_E
dc/dc Controller Enable. When disabled, SYNCO = 0.
0: Powerdown.
1: Enabled.
4—0
DCV[4:0]
dc Prescale Value.
SYNCO Frequency = 960/(2 * (DCV + 1)) kHz.
DCCF may be read by the microcontroller, allowing a read-modify-write operation.
104
Lucent Technologies Inc.
AGERE [ AGERE SYSTEMS ]
