HCS473T/SN Microchip Technology, HCS473T/SN Datasheet - Page 29

• Manufacturer Part Number: HCS473T/SN
• Description: IC KEELOQ 3AXIS TRANSCODER 8SOIC
• Manufacturer: Microchip Technology
• Series: KEELOQ®r
• Type: Code Hopping Encoder and Transponderr

Specifications of HCS473T/SN

• Applications: Access Control Systems
• Mounting Type: Surface Mount
• Package / Case: *
• Lead Free Status / RoHS Status: Request inventory verification / Request inventory verification

3.2.3.4
The transponder reader follows the 3-bit READ com-
mand with one of eight possible 3-bit address options
indicating which 16-bit EEPROM word to retrieve
(Table 3-5) and a 2-bit CRC calculated over the com-
mand and address bits.
The HCS473 retrieves the data and returns the 16-bit
response by creating a 32-bit value containing two cop-
ies of the response (Figure 3-15).
RFRSP determines if the response will be transmitted
on the DATA pin. If enabled, the response will follow the
selected Encoder mode code hopping format with the
hopping code replaced with the 32-bit response. The
transmissions will contain a button code of ‘0000’.
FIGURE 3-15:
 2002 Microchip Technology Inc.
RF Response
Inductive In
(DATA Pin)
(LC Pins)
Previous Command
Wake Sequence
Response
or
READ Command
T
SF
ACK
READ SEQUENCE (RF RESPONSE EXAMPLE)
T
CMD
T
CMD
Command
T
‘100
CMD
CMD
2
’ 3 bits 2 bits
ADR
Address
Preliminary
CRC
CRC
T
READ
T
READ
T
LFRSP determines if the response will be transmitted
on the LC pins. The LC pin response will be the 32-bit
result, modulated PPM format.
If both RFRSP and LFRSP are enabled, the HCS473
will send the response on the DATA pin immediately fol-
lowed by the PPM response on the LC pins. Refer to
Section 3.2.1.7 for further response path details.
The following locations are available to read:
• The 64-bit general purpose user EEPROM.
• The 32-bit serial number. The serial number is
• The16-bit device identifiers #1 and #2.
The next command must begin T
response.
FINH
also transmitted in each code hopping transmis-
sion.
RESPONSE
LF must remain on if following
with consecutive command
or if waiting for LF response
RF Response (RFRSP=1)
T
CMD
Optional Next
Command
HCS473
T
CMD
CMD
DS40035C-page 27
after the read
Command
Next
T
CMD