printed 1998 Apr 20

13

Philips Semiconductors

Product Specification (Rev. 1998 Apr 20)

Advanced Basestation IC

PCF7991AT

Table 11 Configuration bit description

Note

1. In order to achieve fast receiver settling the amplifier and filter characteristics can temporarily be overridden:

3. If the THRESET is set, the threshold generator is disabled and initialized according to the receive signal conditions.

BIT NAME

DESCRIPTION

RESET

CONDITION

FILTERH

main low pass cutoff frequency

0

FILTERL

main high pass cutoff frequency

0

GAIN0

amplifier_0 gain factor

0

GAIN1

amplifier_1 gain factor

1

TXDIS

disable antenna driver

0

0: driver active; 1: driver inactive

HYSTERESIS

data comparator hysteresis

0

0: hysteresis OFF; 1: hysteresis ON

PD

Power-down mode enable

0

0: device active; 1: Power-down mode

PD_MODE

select Power-down mode, if PD = 1

0

0: Idle mode; 1: Power-down mode

FREEZE0

receiver characteristics override

0

see Note 1

FREEZE1

receiver characteristics override

0

see Note 1

ACQAMP

store signal amplitude as reference

for later amplitude comparison

0

see Section 8.5.5

THRESET

reset threshold generation of digitizer

0

see Note 3

FSEL0

clock frequency select LSB

0

see Note 2

FSEL1

clock frequency select MSB

0

DISSMARTCOMP disable smart comparator

0

0: comparator = ON, 1: comparator = OFF

DISLP1

disable main low pass

0

0: low pass = ON, 1: low pass = OFF

FREEZE 1

FREEZE 0

REMARK

0

0

normal operation according to configuration page 0

0

1

main low pass is frozen and main high pass is initialized to QGND

1

0

main low pass is frozen and the time constant of the main high pass is reduced by a

factor of 16 for FILTERH = 0 and by a factor of 8 for FILTERH = 1

1

1

time constant of the main high pass is reduced by a factor of 16 for FILTERH = 0

and by a factor of 8 for FILTERH = 1. Second high pass is initialized to QGND

FSEL0

FSEL1

OSCILLATOR FREQUENCY

0

0

4 MHz

0

1

8 MHz

1

0

12 MHz

0

1

16 MHz