HCS515_11 Datasheet, PDF (16/38 Pages) Microchip Technology – KEELOQ® Code Hopping Decoder stand-alone decoder

HCS515
5.2 Programming Waveform
The programming command consists of the following:
• Command Request Sequence (A to B)
• Command Byte (B to C)
• Configuration Byte (C to D)
• Manufacturer’s Code Eight Data Bytes (D to G)
• Activation and Acknowledge Sequence (G to H)
FIGURE 5-1: PROGRAMMING WAVEFORM
TREQ
TCLKL
TSTART
TCLKH
TDATA
TDS
TDATA
CLK
5.3 Programming Data String
A total of 80 bits are clocked into the decoder. The 8-bit
command byte is clocked in first, followed by the 8-bit
configuration byte and the 64-bit manufacturer’s code.
The data must be clocked in Least Significant bit (LSb)
first. The decoder will then encrypt the manufacturer’s
code using the decoder’s unique 64-bit EEPROM
encoder decryption key. After completion of the pro-
gramming EEPROM, the decoder will acknowledge by
taking the data line high (G to H). If the data line goes
high within 30 ms after the clock goes high, program-
ming also fails.
TDATA
TDATA
TACK
TWTH
μC Data
LSB
MSB
LSB
MSB
LSB
MSB
HCS515
Data
TRESP
START Command Command Byte
A
B
C
Configuration Byte
D
Least Significant Byte
E
LSB
MSB
TWTL
Most Significant Byte Acknowledge
F
G
H
TABLE 5-1: PROGRAMMING COMMAND
Symbol
Parameters
Sugg. Value
TREQ
TRESP
TSTART
TCLKH
TCLKL
TDS
TDATA
TACK
TWTH
TWTL
Note:
Command request time
d.o.d.
Acknowledge time
100
Command request to first command bit
100
Clock high time
100
Clock low time
100
Data hold time
50
Command last bit to data first bit
100
Command acknowledge time
d.o.d.
Acknowledge respond time
100
Clock low to next command
100
d.o.d. - depends on decoder status
These parameters are characterized but not tested
Min.
0.005
10
20
20
20
14
10
30
20
10
Max.
500
1000
1000
1000
1000
1000
1000
240
1000
—
Units
ms
μs
μs
μs
μs
μs
μs
ms
μs
μs
DS40183E-page 16
© 2011 Microchip Technology Inc.