HCS362-I Datasheet, PDF (19/38 Pages) Microchip Technology – KEELOQ Code Hopping Encoder

HCS362
4.6 SYNCHRONOUS MODE
In Synchronous mode, the code word can be clocked
out on DATA using S2 as a clock. To enter Synchro-
nous mode, DATA and S0 must be taken HIGH and
then S2 is taken HIGH. After Synchronous mode is
entered, S0 must be taken LOW. The data is clocked
out on DATA on every rising edge of S2. Auto-shutoff
timer is not disabled in Synchronous mode. This can be
used to implement RF testing.
FIGURE 4-1:
SYNCHRONOUS TRANSMISSION MODE
TPS TPH1 TPH2
DATA
t = 50ms
Preamble
Header
Data
S2
S[1:0]
“01,10,11”
RFEN
TRFON
FIGURE 4-2:
CODE WORD ORGANIZATION (SYNCHRONOUS TRANSMISSION MODE)
Fixed Portion
Encrypted Portion
QUEUE CRC Vlow Button
(2 bits) (2 bits) (1-bit) Status
S2 S1 S0 S3
MSb
Serial Number
(28 bits)
Button
Status
S2 S1 S0 S3
DISC+ OVR Sync Counter
(12 bits)
(16 bits)
69 Data bits
LSb
Transmitted
LSb first.
© 2002 Microchip Technology Inc.
Preliminary
DS40189D-page 19