AT88RF1354_09 ATMEL [ATMEL Corporation], AT88RF1354_09 Datasheet - Page 30

• Manufacturer Part Number: AT88RF1354_09
• Description: 13.56 MHz Type B RF Reader Specification
• Manufacturer: ATMEL [ATMEL Corporation]

Appendix B. The SPI Serial Interface
B.1.
30
The SPI Interface mode is selected by shorting the ISEL pin to V
AT88RF1354 in SPI mode. The ISTAT signal is used for handshaking between the microcontroller and RF reader.
SPI Interface
The AT88RF1354 SPI interface operates as a slave device in SPI mode 0. In SPI mode 0 the polarity and phase of the
serial clock in relation to the data is as follows:
SCK is low when IDLE.
Incoming data on SDI is sampled on the positive edge of SCK.
Outgoing data on SDO is setup on the negative edge of SCK. (The host microcontroller samples SDO on the positive
edge of SCK)
When SSB is high, the device will ignore any SCK and SDI signals. SDO tri-states when SSB is high to prevent SPI
bus contention in systems where the SPI bus is shared with other devices.
ISTAT reports the serial interface status to the microcontroller.
Figure B-1.
A high level on the ISTAT pin signals the host microcontroller that a byte of data is ready to be read from the
AT88RF1354 serial interface. If another byte is immediately available on the serial port, ISTAT will go low for 150 uS,
then return high. ISTAT will remain high until the last bit of the byte is read, when it will return low. All data must be
clocked out of the AT88RF1354 before it can receive a command.
13.56 MHz Type B RF Reader Specification
Microcontroller
(SPI Master)
Serial Interface wiring to SPI Microcontroller
output
MOSI
MISO
input
SCK
SSB
VCC
CC
. Six microcontroller pins are required to operate
ResetB
ISEL
SDO
SCK
SSB
Istat
SDI
AT88RF1354
(SPI Slave)
Reader IC
8547B–RFID–3/09