1997 Jun 24
17
Philips Semiconductors
Product specification
Advanced POCSAG Paging Decoder
PCD5003
Table 13
Index register
Notes
1.
2.
The index register only uses the least significant nibble, the upper 4 bits are ignored.
Writing to registers 0B to 0F has no effect, reading produces meaningless data.
ADDRESS
(1)
REGISTER FUNCTION
ACCESS
00H
00H
01H
02H
03H
04H
05H
05H
06H
07H
08H
09H
0AH
status
control
R
W
real time clock: seconds
real time clock:
1
100
second
alert cadence
alert set-up
periodic interrupt modulus
periodic interrupt counter
RAM write address pointer
EEPROM address pointer
RAM read address pointer
RAM data output
EEPROM data input/output
unused
R/W
R/W
W
W
W
R
R
R/W
R/W
R
R/W
note 2
0BH to 0FH
7.24
External interrupt
The PCD5003 can signal events to an external controller
via an interrupt signal on output INT. The interrupt polarity
is programmable via SPF programming. The interrupt
source is shown in the status register.
Interrupts are generated by the following events (more
than one event possible):
Call data available for output (bit D2)
SRAM pointers becoming equal (bit D3)
Expiry of periodic time-out (bit D7)
Expiry of alert time-out (bit D4)
Change of state in out-of-range indicator (bit D5)
Change of state in battery-low indicator or in receiver
control output RXE (bit D6).
Immediate interrupts are generated by status bits D3, D4,
D6 (RXE monitoring) and D7. Bits D2, D5 and D6 (BAT
monitoring) generate interrupts as soon as the receiver is
disabled (RXE = 0).
When call data is available (D2 = 1) but the receiver
remains switched on, an interrupt is generated at the next
sync word position.
The interrupt output INT is reset after completion of a
status read operation.
7.25
Status/Control register
The status/control register consists of two independent
registers, one for reading (status) and one for writing
(control).
The status register shows the current operating condition
of the decoder and the cause(s) of an external interrupt.
The control register activates/deactivates certain
functions. Tables 14 and 15 show the bit allocations of
both registers.
All status bits will be reset after a status read operation
except for the out-of-range, battery-low and receiver
enable indicator bits (see note 1 to Table 14).
Status bit D0 is set when call reception is started by
detection of an enabled RIC (user address). This does not
generate an interrupt.