RFHCS362G_11 Datasheet, PDF (21/54 Pages) Microchip Technology – KEELOQ® Code Hopping Encoder with UHF ASK/FSK Transmitter

rfHCS362G/362F
TABLE 4-2: CONFIG_0
Bit
Address
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Field
OSC_0
OSC_1
OSC_2
OSC_3
VLOW_0
VLOW_1
VLOW_2
BSEL_0
BSEL_1
MTX_0
MTX_1
GUARD_0
GUARD_1
TIMOUT_0
TIMOUT_1
CTSEL
Description
Oscillator adjust
0000 - nominal
1000 - fastest
0111 - slowest
Values
VLOW select
Bit rate select
Minimum number of code
words
Guard time select
Time-out select
CTSEL
nominal values
000 - 2.0V
001 - 2.1V
010 - 2.2V
011 - 2.3V
100 - 4.0V
101 - 4.2V
110 - 4.4V
111 - 4.6V
00 - TE = 100 μs
01 - TE = 200 μs
10 - TE = 400 μs
11 - TE = 800 μs
00 - 1
01 - 2
10 - 4
11 - 8
00 - 0 ms (1 TE)
01 - 6.4 ms + 2 TE
10 - 25.6 ms + 2 TE
11 - 76.8 ms + 2 TE
00 - No Time-out
01 - 0.8 s to 0.8 s + 1 code word
10 - 3.2 s to 3.2 s + 1 code word
11 - 25.6 s to 25.6 s + 1 code word
0 = TIME bits
1 = CRC bits
4.5 Configuration Words
There are 36 configuration bits stored in the EEPROM
array. They are used by the device to determine trans-
mission speed, format, delays and Guard times. They
are grouped in three Configuration Words:
CONFIG_0, CONFIG_1 and the upper nybble of the
SEED_3 word. A description of each of the bits follows
this section.
4.5.1 OSC
The internal oscillator can be tuned to ±10%. (0000
selects the nominal value, 1000 the fastest value and
0111 the slowest). When programming the device, it is
the programmer’s responsibility to determine the opti-
mal calibration value.
4.5.2 VLOW[0..2]
The low voltage threshold can be programmed to be
any of the values shown in Table 4-2.
4.5.3 BSEL[0..1]
The basic timing element TE, determines the actual
transmission Baud Rate. This translates to different
code word lengths depending on the encoding format
selected (Manchester or PWM), the Header length
selection and the Guard time selection, from approxi-
mately 40 ms up to 220 ms. Refer to Table 4-2 for bit
rate configuration. Refer to Figure 10-3 through
Figure 10-6 for code word timing.
4.5.4 MTX[0..1]
MTX selects the minimum number of code words that
will be transmitted. A minimum of 1, 2, 4 or 8 code
words will be transmitted.
Note:
If MTX and BSEL settings in combination
require a transmission sequence to
exceed the TIMOUT setting, TIMOUT will
take priority.
© 2011 Microchip Technology Inc.
DS41189B-page 21