HCS412I MICROCHIP [Microchip Technology], HCS412I Datasheet - Page 28

• Manufacturer Part Number: HCS412I
• Description: KEELOQ Code Hopping Encoder and Transponder
• Manufacturer: MICROCHIP [Microchip Technology]

HCS412
4.4.2
In addition to enabling anticollision, this mode adds that
all HCS412 responses and Acknowledges are echoed
on the DATA output line. Responses are first transmit-
ted on the DATA line, followed by the equivalent data
transmitted
Figure 4-17).
FIGURE 4-16: RF ECHO OPTION AND READ COMMAND
FIGURE 4-17: RF ECHO OPTION AND IFF COMMAND
FIGURE 4-18: RF ECHO OPTION AND REQUEST HOPPING CODE COMMAND
DS41099C-page 28
Inductive
Inductive
Inductive (LF)
DATA (RF)
DATA (RF)
LF Communication from reader to HCS412
LF Communication from HCS412 to reader
DATA (RF)
(LF)
LF Communication from reader to HCS412
LF Communication from HCS412 to reader
(LF)
LF Communication from reader to HCS412
LF Communication from HCS412 to reader
ANTICOLLISION AND RF ECHO
(LFSP = 11)
Field
ACK
T
PU
on
T
ATO
the
ACK
Request Hopping
Code Opcode
LF
T
ATO
LC
lines
(Figure 4-16,
T
OTH
T
OTH
Preliminary
LF communication from the token to the transponder
reader has much less range than LF communication
from the reader to the token. Transmitting the informa-
tion on the DATA line increases communication range
by enabling longer range RF talk back.
The information is sent on the DATA line first to benefit
longer range passive-entry authentication times.
Response
16-Bit
32-Bit Response
Response
16-Bit
2002 Microchip Technology Inc.
32-Bit PPM
Response
Next
Field
Ack