HCS361_11 MICROCHIP [Microchip Technology], HCS361_11 Datasheet - Page 15

• Manufacturer Part Number: HCS361_11
• Manufacturer: MICROCHIP [Microchip Technology]

5.4
The Auto-shutoff function automatically stops the
device from transmitting if a button inadvertently gets
pressed for a long period of time. This will prevent the
device from draining the battery if a button gets
pressed while the transmitter is in a pocket or purse.
This function can be enabled or disabled and is
selected by setting or clearing the time-out bit
(Section 3.5.13). Setting this bit will enable the function
(turn Auto-shutoff function on) and clearing the bit will
disable the function. Time-out period is approximately
25 seconds.
5.5
The V
(Figure 3-2) and will be transmitted as a one if the
operating voltage has dropped below the low voltage
trip point, typically 3.8V at 25°C. This V
transmitted so the receiver can give an indication to the
user that the transmitter battery is low.
5.6
During normal transmission the LED output is LOW
while the data is being transmitted and high during the
guard time. Two voltage indications are combined into
one bit: V
of V
© 2011 Microchip Technology Inc.
LOW
LOW
while data is being transmitted.
Auto-shutoff
V
LOW
LED Output Operation
LOW
bit is transmitted with every transmission
. Table 5-1 indicates the operation value
: Voltage LOW Indicator
LOW
signal is
FIGURE 5-2:
If the supply voltage drops below the low voltage trip
point, the LED output will be toggled at approximately
1Hz during the transmission.
TABLE 5-1:
*See also FLASH operating modes.
4.5
3.5
2.5
1.5
Supply Voltage
4
3
2
Approximate
-40
3.8V → 2.2V
Max → 3.8V
2.2V → Min
V
V
V
LOW
LOW
LOW
V
=0
=1
=0
LOW
Vlow Bit
V
Temperature
LOW
AND LED VS. V
25
0
1
0
Nominal Trip Point
Trip Point VS.
Nominal Trip
HCS361
3.8V
Point
DS40146F-page 15
LED Operation*
Flashing
Normal
Normal
DD
85
3.5
2V