HCS362_11 Datasheet, PDF (12/46 Pages) Microchip Technology – KEELOQ® Code Hopping Encoder Non-volatile synchronization data

HCS362
3.1.4 MINIMUM CODE WORDS
MTX[0..1] configuration bits selects the minimum
number of code words that will be transmitted. If the
button is released after 1.6 s (or greater) and MTX code
words have been transmitted, the code word being
transmitted will be terminated. The possible values are:
00 - 1
01 - 2
10 - 4
11 - 8
FIGURE 3-6: TIME BITS OPERATION
3.1.5 TIME BITS
The time bits indicate the duration that the inputs were
activated:
00 - immediate
01 - after 0.8 s
10 - after 1.6 s
11 - after 2.4 s
The TIME bits are incremented every 0.8 s and does
not wrap once it reaches ‘11’.
Time information is alternative to the CRC bits availabil-
ity and is selected by the CTSEL configuration bit.
S[3210]
DATA
Time bits = 00
Time
TTD
0s
= One Code Word
Time bits set internally to 01 Time bits set internally to 10
Time bits actually output
Time bits actually output
0.8 s
1.6 s
2.4 s
3.2 LED Output
The LED pin will be driven LOW periodically while the
HCS362 is transmitting data, in order to switch on an
external LED.
The duty cycle (TLEDON/TLEDOFF) can be selected
between two possible values by the configuration
option (LED).
FIGURE 3-7: LED OPERATION (LED = 1)
S[3210]
VDD > VLOW
LED
TLEDON TLEDOFF
TLEDON = 25 ms _{TLEDOFF = 500 ms}
VDD < VLOW
LED
The same configuration option determines whether
when the VDD Voltage drops below the selected VLOW
trip point, the LED will blink only once or stop blinking.
FIGURE 3-8: LED OPERATION (LED = 0)
S[3210]
VDD > VLOW
TLEDON
TLEDOFF
LED
TLEDON = 200 ms TLEDOFF = 800 ms
VDD < VLOW
LED
Note:
When the HCS362 encoder is used as
a Dual Encoder the LED pin is used as
a SHIFT input (Figure 2-2). In such a
configuration the LED is always ON
during transmission. To keep power
consumption low, it is recommended
to use a series resistor of relatively
high value. VLOW information is not
available when using the second
Encryption Key.
DS40189E-page 12
© 2011 Microchip Technology Inc.