HCS500 Datasheet, PDF (9/24 Pages) Microchip Technology – KEELOQ CODE HOPPING ENCODER

HCS500
4.2.3 COMMAND ACTIVATION TIMES
The command activation time (Table 4-1) is defined as
the maximum time the microcontroller has to wait for a
response from the decoder. The decoder will abort and
service the command request. The response time
depends on the state of the decoder when the com-
mand mode is requested.
4.2.4 DECODER COMMANDS
The command byte specifies the operation required by
the controlling microcontroller. Table 4-2 lists the com-
mands.
TABLE 4-1: COMMAND ACTIVATION TIMES
Decoder State
While receiving transmissions
During the validation of a received transmission
During the update of the sync counters
During learn
TABLE 4-2: DECODER COMMANDS
Instruction
Command Byte
READ
WRITE
ACTIVATE_LRN
ERASE_ALL
PROGRAM
F0₁₆
E1₁₆
D2₁₆
C3₁₆
B4₁₆
Min
Max
—
2 1/2 BPW_MAX = 2.7 ms
—
3 ms
—
40 ms
—
170 ms
Operation
Read a byte from user EEPROM
Write a byte to user EEPROM
Activate a learn sequence on the decoder
Activate an erase all function on the decoder
Program manufacturer’s code and configuration byte
© 1997 Microchip Technology Inc.
Preliminary
DS40153B-page 9