HCS301-/P MICROCHIP [Microchip Technology], HCS301-/P Datasheet - Page 8

• Manufacturer Part Number: HCS301-/P
• Description: KEELOQ CODE HOPPING ENCODER
• Manufacturer: MICROCHIP [Microchip Technology]

HCS301
of unique values. This can be done by programming
OVR0 and OVR1 to 1s at the time of production. The
encoder will automatically clear OVR0 the first time that
the synchronization value wraps from 0xFFFF to
0x0000 and clear OVR1 the second time the counter
wraps. Once cleared, OVR0 and OVR1 cannot be set
again, thereby creating a permanent record of the
counter overflow. This prevents fast cycling of 64K
counter. If the decoder system is programmed to track
the overflow bits, then the effective number of unique
synchronization values can be extended to 196,608.
3.6.3
BSL0 and BSL1 select the speed of transmission and
the code word blanking. Table 3-3 shows how the bits
are used to select the different baud rates and
Section 5.7 provides detailed explanation in code word
blanking.
TABLE 3-3:
DS21143B-page 8
BSL1
0
0
1
1
BSL0
(BSL0, BSL1)
BAUD RATE SELECT BITS
0
1
0
1
BAUD RATE SELECT
Basic Pulse
Element
400 s
200 s
100 s
100 s
Code Words
Transmitted
1 out of 2
1 out of 2
1 out of 4
All
3.6.4
The low voltage trip point select bit is used to tell the
HCS301 what
will be used by the device to determine when to send the
voltage low signal to the receiver. When this bit is set to
a one, the
9V or 12V
is assumed to be 6.0 volts. Refer to Figure 3-1 for volt-
age trip point.
FIGURE 3-1:
Volts (V)
V
V
DD
LOW VOLTAGE TRIP POINT
SELECT
DD
5.5
5.0
4.5
4.0
3.5
3.0
2.5
9.0
8.5
8.0
7.5
7.0
level. If the bit is set low, then the
V
-40
level is assumed to be operating from a
DD
level is being used. This information
-20
VOLTAGE TRIP POINTS
BY CHARACTERIZATION
0
2001 Microchip Technology Inc.
20 40
Temp (C)
V
V
LOW
LOW
60 80
sel = 1
sel = 0
100
V
Max
Min
Max
Min
LOW
V
DD
level