HCS512-ISN MICROCHIP [Microchip Technology], HCS512-ISN Datasheet - Page 5

• Manufacturer Part Number: HCS512-ISN
• Description: KEELOQ CODE HOPPING DECODER
• Manufacturer: MICROCHIP [Microchip Technology]

3.0
3.1
The HCS512 activates the S3, S2, S1 & S0 outputs
according to Table 3-1 when a new valid code is
received. The outputs will be activated for approxi-
mately 500 ms. If a repeated code is received during
this time, the output extends for approximately 500 ms.
TABLE 3-1:
FIGURE 3-1:
FIGURE 3-2:
A 1-wire PWM or 2-wire synchronous interface can be used.
In 1-wire mode, the data is transmitted as a PWM signal with a basic pulse width of 400 s.
falling edge. The start and stop bits are ‘1’.
FIGURE 3-3:
In 2-wire mode, synchronous mode PWM bits start on the rising edge of the clock, and the bits must be sampled on the
Function
1997 Microchip Technology Inc.
Code
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
START
START
CLK
DATA
DESCRIPTION OF FUNCTIONS
Parallel Interface
S3
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
FUNCTION OUTPUT TABLE
DATA OUTPUT FORMAT
STATUS MESSAGE FORMAT
PWM TRANSMISSION FORMAT
S3
0
600 s
Start
1200 s
S2
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
S2
0
S3
S1
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
S1
S2
“1”
0
S0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
S1
S0
0
RESULT
S0
“0”
V
LOW
3.2
The decoder has a PWM/Synchronous interface con-
nection to microcontrollers with limited I/O. An output
data stream is generated when a valid transmission is
received. The data stream consists of one start bit, four
function bits, one bit for battery status, one bit to indi-
cate a repeated transmission, two status bits, and one
stop bit. (Table 3-1). The DATA and CLK lines are used
to send a synchronous event message.
A special status message is transmitted on the second
pass of learn. This allows the controlling microcontroller
to determine if the learn was successful (Result = 1)
and if a previous transmitter was overwritten (Overwrite
= 1). The status message is shown in Figure 3-2.
Table 3-2 show the values for TX1:0 and the number of
transmitters learned.
TABLE 3-2:
V
TX1
LOW
0
0
1
1
REPEAT
OVRWR
Serial Interface
RPT Reserved Reserved Stop
STATUS BITS
TX0
0
1
0
1
TX1
TX1
Number of Transmitters
TX0
TX0
HCS512
DS40151C-page 5
Three
Four
One
Two
STOP
STOP