HCS500 Datasheet, PDF (22/24 Pages) Microchip Technology – KEELOQ CODE HOPPING ENCODER

HCS500
8.1.7 ERASE ALL COMMAND
Symbol
TERA
TACK
TRESP
TACK2
Parameters
Learn command activation time
Decoder acknowledge time
Microcontroller acknowledge
response time
Decoder data line low
8.1.8 PROGRAMMING COMMAND
Symbol
TPP1
TPP2
TPP3
TPP4
TCLKH
TCLKL
FCLK
TDS
TCMD
TACK
TWT2
TALW
Parameters
Command request time
Decoder acknowledge time
Start command mode to first
command bit
Data line low before tri-stated
Clock high time
Clock low time
Clock frequency
Data hold time
Command validate time
Command acknowledge time
Acknowledge respond time
Data low after clock low
Standard Operating Conditions (unless otherwise specified):
Commercial (C): 0°C ≤ TA ≤ +70°C
Industrial (I):
-40°C ≤ TA ≤ +85°C
Min
Typ
Max
Units
20
—
1000
µs
20
—
210
ms
20
—
1000
µs
—
—
10
µs
Standard Operating Conditions (unless otherwise specified):
Commercial (C): 0°C ≤ TA ≤ +70°C
Industrial (I):
-40°C ≤ TA ≤ +85°C
Min
Typ
Max
Units
—
—
500
ms
—
—
1
ms
20
—
1000
µs
—
—
5
µs
20
—
1000
µs
20
—
1000
µs
500
—
25000
Hz
—
—
5
µs
—
—
10
µs
30
—
240
ms
20
—
1000
µs
—
—
10
µs
FIGURE 8-2: TYPICAL MICROCONTROLLER INTERFACE CIRCUIT
VCC
RF
Receiver
U2
XXX4123
A0
A1
A2
VSS
VCC
WP
SCL
SDA
8
7
6
5
24LC02B
1K
1
2
3
4
U1
VDD
EECLK
EEDAT
MCLR
VSS
RFIN
SCLK
SDAT
8
7
6
5
HCS500
RST
R3
10K
Microcontroller
VCC
U3
POWER SUPPLY
SUPERVISOR 4.5V
VI ^G VO
N
D
In-circuit
Programming
Probe Pads
Note: Because each HCS500 is individually matched to its EEPROM, in-circuit programming is
strongly recommended.
DS40153B-page 22
Preliminary
© 1997 Microchip Technology Inc.