PCD5008 データシートの表示（PDF） - Philips Electronics
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PCD5008 Datasheet PDF : 64 Pages
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Philips Semiconductors
FLEX™ Pager Decoder
Product specification
PCD5008
8.3.3 SPI TRANSFER INITIATED BY THE HOST
The following steps occur when the host initiates an SPI
packet transfer, see Fig.5 for event timings:
1. The host selects the PCD5008 by driving the
SS pin LOW.
2. The PCD5008 indicates that it is ready to start the
SPI transfer by driving the READY pin LOW.
3. The host clocks each of the 32 bits of the SPI packet
by pulsing SCK. Both the host and the PCD5008
sample data on the rising edge of SCK. Packets are
sent MSB first.
4. The PCD5008 pulls the READY line HIGH, to indicate
that the transfer is complete.
5. The host waits until the READY line is pulled HIGH,
then de-selects the PCD5008 SPI by driving the
SS pin HIGH.
6. The first 5 steps are repeated for each additional
packet.
handbook, full pagSeSwidth
(1)
(5)
READY
(2)
(4)
SCK
(3)
MOSI
D31
D1 D0
D31
D1 D0
D31
D1 D0
MISO
Zo(off)
D31
D1 D0 Zo(off)
D31
D1 D0 Zo(off)
D31
D1 D0 Zo(off)
MGK262
Numbers within parenthesis refer to sequence numbers, see Section 8.3.3.
Fig.5 Typical multiple SPI transfers initiated by the host.
8.3.4 SPI TRANSFER INITIATED BY THE DECODER
The following steps occur when the PCD5008 initiates an
SPI packet transfer, see Fig.6 for event timings:
1. The PCD5008 initiates the SPI transfer by driving the
READY pin LOW.
2. If the PCD5008 is not already selected, the host
selects the PCD5008 SPI by driving the SS pin LOW.
3. The host clocks each of the 32 bits of the SPI packet
by pulsing SCK. Both the host and the PCD5008
sample data on the rising edge of SCK. Packets are
sent MSB first.
4. The PCD5008 pulls the READY line HIGH, to indicate
that the transfer is complete.
5. The host may then either de-select the SPI interface of
the PCD5008 (Fig.7) by driving the SS pin HIGH or
maintain SS LOW to continue sending packets to the
PCD5008.
1998 Jun 17
9
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