Rainbow Electronics AT88RF1354 - Manual (Page 34)

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13.56 MHz Type B RF Reader
8547A −RFID−10/08
C.2. TWI Device Address
The TWI device address is selected with the ADDR address select pin of the AT88RF1354.
Figure C-2. TWI Device Address
TWI Device Address
ADDR Pin
Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
TWI_R TWI_W
V
SS
0 1 0 1 0 0 0 $51 $50
V
CC
1 1 0 1 0 1 0 $D5 $D4
All other values are NOT supported
The AT88RF1354 device requires an 8-bit device address word following a start condition to enable the chip for a
read or write operation. The device address word consists of a 7 bit address followed by a read/write select bit. The
write bit should be set when sending command packets to AT88RF1354. The read bit should be set when retrieving
response packets from AT88RF1354.
Upon a successful compare of the device address, the AT88RF1354 will pull the SDI output low for 1 bit period,
sending a TWI ACK bit. If an address compare is unsuccessful, the device will return to an idle state and the SDA /
SDI line will remain pulled up by the external pull-up resistor, effectively sending a TWI NACK bit.
The AT88RF1354 ignores TWI communication packets that do not begin with a matching device address. This allows
other TWI devices to share the bus with the AT88RF1354 reader IC.