AT24RF08-EK Atmel, AT24RF08-EK Datasheet - Page 12

• Manufacturer Part Number: AT24RF08-EK
• Description: KIT EVAL FOR AT24RF08CN-10SC
• Manufacturer: Atmel
• Type: Dual Access EEPROMr

Specifications of AT24RF08-EK

• Contents: Atmel Asset ID Kit CDROM, 4 RFID Tags, Reader with Serial Port Cable and 9V Power Supply
• For Use With/related Products: AT24RF08C
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Transmission: Encoding and Modulation
Data is transmitted to the reader using resistive modulation
which is implemented as a variable modulation resistor
switched across the coil pins. Data from the EEPROM is
encoded usi ng Miller Encoding befor e driv ing the
modulation resistor. If the output of the Miller Encoder is a
1, then the modulator resistor is turned on and vice versa.
In Miller Encoding, if the data state is a 1, there is a
transition in the middle of the bit time. If the data state is a
0, there is no transition if the next data bit is a 1 or a
transition at the end of the bit time if the next data state is a
0.
Each data or ID group transmitted (other than the header)
includes a start bit which has a value of 1. This is always
Data Transmission
12
AT24RF08C
interpreted as a transition from modulator-off to modulator-
on in the middle of the start bit time, preventing a half-bit
time modulation pulse. Data is transmitted from the chip at
a rate of one bit (into the encoder) for each 16 carrier
cycles. After the data has been transmitted, a single stop
bit having the value of 0 will be transmitted. Depending on
the state of the last parity bit, this will be either one cycle of
modulation or one cycle of no modulation. The following
diagram shows the functional signal waveforms for data
transmission.