hcs362 Microchip Technology Inc., hcs362 Datasheet - Page 17

• Manufacturer Part Number: hcs362
• Description: Keeloq Code Hopping Encoder
• Manufacturer: Microchip Technology Inc.

4.5.5
The Guard time between code words can be set to 0
ms, 6.4 ms, 25.6 ms and 76.8 ms. If during a series of
code words, the output changes from Hopping Code to
Seed the Guard time will increase by 3 x T
TABLE 4-3:
4.5.7
The discrimination bits are used to validate the
decrypted code word. The discrimination value is typi-
cally programmed with the 10 Least Significant bits of
the serial number or a fixed value.
4.5.8
The overflow bits are used to extend the possible code
combinations to 192K. If the overflow bits are not going
to be used they can be programmed to zero.
4.5.9
If
ted. If
bit function code are transmitted.
XSER
2002 Microchip Technology Inc.
Address
XSER
Bit
10
11
12
13
14
15
...
0
1
2
8
9
is enabled a 32-bit serial number is transmit-
GUARD
DISC[0..9]
OVR[0..1]
XSER
is disabled a 28-bit serial number and a 4-
CONFIG_1
DISC_0
DISC_1
DISC_2
DISC_8
DISC_9
SEED_0
SEED_1
OVR_0
OVR_1
SEEDC
XSER
Field
...
Extended Serial Number
Discrimination bits
E
.
Seed Control
Seed options
Description
Overflow
Preliminary
4.5.6
The transmission time-out can be set to 0.8 s, 3.2 s,
25.6 s or no time-out. After the time-out period, the
encoder will stop transmission and enter a low power
Shutdown mode.
4.5.10
The seed value which is transmitted on key combina-
tions (
enabled for a limited number of transmissions deter-
mined by the initial counter value.
In limited Seed mode, the device will output the seed if
the sync counter (Section 4.2) is from 00hex to 7Fhex.
For a counter higher than 7F, a normal hopping code
will be output.
4.5.11
SEEDC
and
=
(
SEEDC
Note:
1
DISC
OVR
0
1
0
1
00
01
10
11
). The delay before seed transmission is 1.6 s for
0101
- Disable
- Enable
= Seed transmission on:
= Seed transmission on:
S[3210]
S[3210]
S[3210]
S[3210]
0011
- Limited Seed (Permanent and Delayed)
- Permanent and Delayed Seed
- Permanent Seed only
- No Seed
[
1:0
selects between seed transmission on
=
[
9:0
(
0
Whenever a SEED code word is output,
the 4 function bits (Figure 7-4) will be set to
all ones [
SEEDC
TIMOUT[0..1]
SEED[0..1]
SEEDC
) and (
) and 3.2 s for (
]
]
=
=
=
=
1001
0001
0011
1001
=
0101
1,1,1,1
0
) and
Values
) can be disabled, enabled or
(delay 1.6 s)
(delay 3.2 s)
(immediate)
(immediate)
SEEDC
0011
].
HCS362
and
=
DS40189D-page 17
1
).
1001
(
SEEDC
0001