PCD5013H/F1 데이터 시트보기 (PDF) - Philips Electronics

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PCD5013H/F1

FLEX™roaming decoder II

Philips Electronics 

Philips Semiconductors

FLEX™ roaming decoder II

Product specification

PCD5013

8.3 Serial Peripheral Interface (SPI)

8.3.1 GENERAL

All data communication between the PCD5013 and the

host is done via the SPI using 32-bit data packets at data

rates up to 1 Mbits/s. SPI transfers are full-duplex and can

be initiated by either the host which acts as the SPI master

providing the data clock for packet transfer, or the

PCD5013 as an SPI slave.

The host can send packets to configure or control the

PCD5013 or a checksum packet to validate SPI

communication (Section 8.4.2). The PCD5013 buffers

data packets, relating to received data, into a 32 packet

transmit buffer. The PCD5013 can send either a status

packet, a part ID packet, or packets from the transmit

buffer. In the event of a buffer overflow, the PCD5013

stops decoding and clears the transmit buffer.

8.3.2 SPI INTERCONNECT

Connection on the PCD5013 consists of a READY pin and

4 SPI pins (SS, SCK, MOSI and MISO):

READY: output signal; indicates that data is available

from the PCD5013

SS: SPI select; used as PCD5013 chip select

SCK: serial clock; output from the host used for clocking

data

MOSI: master output slave input; data output from the

host

MISO: master input slave output; data output from the

PCD5013.

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 PCD5013 by driving the

SS pin LOW.

2. The PCD5013 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 PCD5013

sample data on the rising edge of SCK. Packets are

sent MSB first.

4. The PCD5013 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 PCD5013 SPI by driving the

SS pin HIGH.

6. The first 5 steps are repeated for each additional

packet.

8.3.4 SPI TRANSFER INITIATED BY THE DECODER

The following steps occur when the PCD5013 initiates an

SPI packet transfer, see Fig.6 for event timings:

1. The PCD5013 initiates the SPI transfer by driving the

READY pin LOW.

2. If the PCD5013 is not already selected, the host

selects the PCD5013 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 PCD5013

sample data on the rising edge of SCK. Packets are

sent MSB first.

4. The PCD5013 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 PCD5013 (Fig.7) by driving the SS pin HIGH or

maintain SS LOW to continue sending packets to the

PCD5013.

1999 Apr 12

9

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