HCS515_11 Datasheet, PDF (15/38 Pages) Microchip Technology – KEELOQ® Code Hopping Decoder stand-alone decoder

5.0 DECODER PROGRAMMING
The memory is divided between system memory that
stores the transmitter information (read protected) and
user memory (read/write). Commands to access the
user memory are described in Sections 4.2.5 and
4.2.6.
The following information stored in system memory
needs to be programmed before the decoder can be
used:
• 64-bit manufacturer’s code
• Decoder configuration byte
Note 1: These memory locations are read pro-
tected and can only be written to using
the program command with the device
powered up.
2: The contents of the system memory is
encrypted by a unique 64-bit key that
is stored in the HCS515. To initialize
the system memory, the HCS515’s
program command must be used.
HCS515
5.1 Configuration Byte
The decoder is configured during initialization by set-
ting the appropriate bits in the configuration byte. The
following table list the options:
Bit Mnemonic
Description
0 LRN_MODE Learning mode selection
LRN_MODE = 0 – Normal
Learn
LRN_MODE = 1 – Secure
Learn
1 Not Used Reserved
2 REPEAT Repeat Transmission enable
0 = Disable
1 = Enabled
3 Not Used Reserved
4 Not Used Reserved
5 Not Used Reserved
6 Not Used Reserved
7 Not Used Reserved
5.1.1 LRN_MODE
LRN_MODE selects between two learning modes. With
LRN_MODE = 0, the Normal (serial number derived)
mode is selected; with LRN_MODE = 1, the Secure
(seed derived) mode is selected. See Section 6.0 for
more detail on learning modes.
5.1.2 REPEAT
The HCS515 can be configured to indicate repeated
transmissions. In a stand-alone configuration, repeated
transmissions must be disabled.
© 2011 Microchip Technology Inc.
DS40183E-page 15