HCS512-P datasheet(6/20 Pages) MICROCHIP

Part #	HCS512-P

Description	KEELOQ CODE HOPPING DECODER

Download	20 Pages

Scroll/Zoom	100%

Manufacturer	MICROCHIP [Microchip Technology]

Direct Link	http://www.microchip.com

Logo

6 / 20 page

HCS512

DS40151C-page 6

4.0

DECODER OPERATION

4.1

Learning a Transmitter to a Receiver

Either the serial number-based learning method or the

seed-based learning method can be selected. The

learning method is selected in the conﬁguration byte. In

order for a transmitter to be used with a decoder, the

transmitter must ﬁrst be ‘learned’. When a transmitter is

learned to a decoder, the decoder stores the encoder

key, a check value of the serial number and current syn-

chronization value in EEPROM. The decoder must

keep track of these values for every transmitter that is

learned. The maximum number of transmitters that can

be learned is four. The decoder must also contain the

Manufacturer’s Code in order to learn a transmitter. The

Manufacturer’s Code will typically be the same for all

decoders in a system.

The HCS512 has four memory slots. After an “erase all”

procedure, all the memory slots will be cleared. Erase

all is activated by taking LRNIN low for approximately

10 seconds. When a new transmitter is learned, the

decoder searches for an empty memory slot and stores

the transmitter’s information in that memory slot. When

all memory slots are full, the decoder randomly over-

writes existing transmitters.

4.1.1

LEARNING PROCEDURE

Learning is activated by taking the LRNIN input low for

longer than 64 ms. This input requires an external pull-

up resistor.

To learn a new transmitter to the HCS512 decoder, the

following sequence is required:

1.

Enter learning mode by pulling LRNIN low for

longer than 64 ms. The LRNOUT output will go

high.

2.

Activate the transmitter until the LRNOUT output

goes low indicating reception of a valid code

(hopping message).

3.

Activate the transmitter a second time until the

LRNOUT toggles for 4 seconds (in secure learn-

ing mode, the seed transmission must be trans-

mitted during the second stage of learn by

activating the appropriate buttons on the trans-

mitter).

If LRNIN is taken low momentarily during the

learn status indication, the indication will be ter-

minated. Once a successful learning sequence

is detected, the indication can be terminated

allowing quick learning in a manufacturing setup.

4.

The transmitter is now learned into the decoder.

5.

Repeat steps 1-4 to learn up to four transmitters.

6.

Learning will be terminated if two non-sequential

codes were received or if two acceptable codes

were not decoded within 30 seconds.

The following checks are performed on the decoder to

determine if the transmission is valid during learn:

• The ﬁrst code word is checked for bit integrity.

• The second code word is checked for bit integrity.

• The hopping code is decrypted.

• If all the checks pass, the serial number and syn-

chronization counters are stored in EEPROM

memory.

Figure 4-1 shows a ﬂow chart of the learn sequence.

FIGURE 4-1:

LEARN SEQUENCE

4.2

Validation of Codes

The decoder waits for a transmission and checks the

serial number to determine if the transmitter has been

learned. If learned, the decoder decrypts the encrypted

portion of the transmission using the encoder key. It

uses the discrimination bits to determine if the decryp-

tion was valid. If everything up to this point is valid, the

synchronization value is evaluated.

Enter Learn

Mode

Wait for Reception

of Second

Compare Discrimination

Value with Serial Number

Use Generated Key

to Decrypt

Equal

Serial number check value

Synchronization counter

?

Exit

Learn successful. Store:

Learn

Unsuccessful

No

Yes

Wait for Reception

of a Valid Code

Non-Repeated

Valid Code

Generate Key

from Serial Number

or Seed Value

Encoder Key

Similar Part No. - HCS512-P

Manufacturer	Part #	Datasheet	Description
Microchip Technology	HCS512-/P	317Kb / 26P	KEELOQ짰 Code Hopping Decoder 2002
	HCS512-/SO	317Kb / 26P	KEELOQ짰 Code Hopping Decoder 2002
	HCS512-I/P	317Kb / 26P	KEELOQ짰 Code Hopping Decoder 2002
	HCS512-I/SO	317Kb / 26P	KEELOQ짰 Code Hopping Decoder 2002

More results

Similar Description - HCS512-P

Manufacturer	Part #	Datasheet	Description
Microchip Technology	HCS515-I	313Kb / 32P	KEELOQ Code Hopping Decoder 01/18/02
	HCS515	332Kb / 28P	KEELOQ CODE HOPPING DECODER 2002
	HCS515	324Kb / 32P	KEELOQ Code Hopping Decoder 01/18/02
	HCS500-I	403Kb / 34P	KEELOQ Code Hopping Decoder 01/18/02
	HCS361	343Kb / 24P	KEELOQ CODE HOPPING ENCODER 1996 - 1997
	HCS320	435Kb / 32P	KEELOQ Code Hopping Encoder 2001
	HCS362-I	489Kb / 38P	KEELOQ Code Hopping Encoder 01/18/02
	HCS370	518Kb / 36P	KEELOQ Code Hopping Encoder 2002
	HCS200	150Kb / 16P	KEELOQ CODE HOPPING ENCODER 1996
	HCS360	211Kb / 24P	KEELOQ CODE HOPPING ENCODER 1996-1997

More results

HCS512-P Datasheet(PDF) 6 Page - Microchip Technology

HCS512-P Datasheet(HTML) 6 Page - Microchip Technology

Similar Part No. - HCS512-P

Similar Description - HCS512-P

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Datasheet Download

Link URL