PCD3316 Datasheet, PDF (7/30 Pages) NXP Semiconductors – Caller-ID on Call Waiting CIDCW receiver

Philips Semiconductors
PCD3316
CIDCW receiver
The 32.768 kHz clock signal must be available. The LOW-BAT Indication bit does not
generate interrupts, thus the bit should be polled.
7.6 Level detect
U _{When the input signal level on the FSK or the CAS input (the one that is selected) is}
below a threshold of typically −40 dBm, the Low Level Status bit will be set (Interrupt
n register, bit 4). The level detector can be used to observe a carrier loss during FSK
transmission and to detect the ‘Idle State Tone Alert Signal’ for British Telecom. The
r _{signal power on the input can be monitored by polling the register bit since it will not}
e _{generate an interrupt. Signal power is measured in a frequency band corresponding}
to the selected operation mode, FSK (1000 to 2200 Hz) or CAS (2000 to 2800 Hz).
st_{The Low Level Status bit will be updated every 8 ms. When FSK and CAS are both}
rdisabled the signal level on the FSK input is measured. The 32.768 kHz clock signal
i^{must be available.}
ct _{7.7 Time base}
e _{The 32.768 kHz oscillator is used to generate either a 1 second or a 1 minute}
d ^{interrupt signal. If the TB on/off bit is set (Mode register 2, bit 6) every second or}
minute an interrupt is generated and MIN Interrupt and/or SEC Interrupt bits
(Interrupt register, bit 7 and 6) are set. After reading the Interrupt register the interrupt
is cleared.
The SEC/MIN (Mode register 2, bit 5) selects whether every second (SEC/MIN is set)
or every minute (SEC/MIN is cleared) an interrupt is generated. All possible
selections are shown in Table 3. Resetting bit TB on/off in Mode register 2 (bit 6) will
only disable time base interrupts, and the 32.768 kHz oscillator will continue to run.
7.8 Interrupt
The interrupt request output (IRQ) is active HIGH by default. The polarity of the IRQ
output can be made active LOW by the INT Polarity HIGH/LOW bit (Mode register 1,
bit 3). The IRQ pin is in 3-state when not active, so an external pull-up or pull-down
resistor is required. The interrupt cause is indicated by the flags in the Interrupt
register. Interrupt flags are set by hardware but must be reset by software. All flags of
the Interrupt register are reset when the register is read via I²C-bus interface.
The IRQ pin is deactivated at the positive edge of SCL which reads the first data bit of
the Interrupt register. The IRQ pin will stay inactive for one SCL cycle. IRQ can
handle a next interrupt after the next positive edge of SCL.
Table 3: Selection of interrupt modes
Mode register 2 (CIDMD2) Interrupt register (CIDINT) Interrupt
TB on/off SEC/MIN MIN Interrupt SEC Interrupt
(CIDMD2.6) (CIDMD2.5) (CIDINT.7) (CIDINT.6)
0
X ^[1]
0
0
no time base interrupt (time base is reset)
1
0
1
0
every minute an interrupt is generated; no second interrupt
1
1
1
1
every second an interrupt is generated; every minute an
interrupt is generated
[1] X = don’t care.
9397 750 04824
Product specification
11 March 1999
© Philips Electronics N.V. 1999. All rights reserved.
7 of 30