HCS201-I/SN Microchip Technology, HCS201-I/SN Datasheet - Page 13

• Manufacturer Part Number: HCS201-I/SN
• Description: IC CODE HOPP ENCODER 7FUNC 8SOIC
• Manufacturer: Microchip Technology
• Type: Code Hopping Encoderr

Specifications of HCS201-I/SN

• Applications: Remote Secure Access, Keyless Entry
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Ic Function: Encoder IC
• Supply Voltage Range: 3.5V To 13V
• Operating Temperature Range: -40°C To +85°C
• Digital Ic Case Style: SOIC
• No. Of Pins: 8
• Peak Reflow Compatible (260 C): Yes
• Termination Type: SMD
• Rohs Compliant: Yes
• Filter Terminals: SMD
• Leaded Process Compatible: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

6.0
When using the HCS201 in a system, the user will have
to program some parameters into the device including
the serial number and the secret key before it can be
used. The programming cycle allows the user to input
all 192 bits in a serial data stream, which are then
stored internally in EEPROM. Programming will be
initiated by forcing the DATA line high, after the S2 line
has been held high for the appropriate length of time
line (Table 6-1 and Figure 6-1). After the Program
mode is entered, a delay must be provided to the
device for the automatic bulk write cycle to complete.
This will write all locations in the EEPROM to an all
zeros pattern. The device can then be programmed by
clocking in 16 bits at a time, using S2 as the clock line
and DATA as the data in line. After each 16-bit word is
loaded, a programming delay is required for the internal
program cycle to complete. This delay can take up to
FIGURE 6-1:
FIGURE 6-2:
(Clock)
(Clock)
Note 1: S0 and S1 button inputs to be held to ground during the entire programming sequence.
DATA
(Data)
DATA
(Data)
2001 Microchip Technology Inc.
S2
S2
Note: If a Verify operation is to be done, then it must immediately follow the Program cycle.
End of Programming Cycle
PROGRAMMING THE HCS201
Enter Program
Bit190
T
PS
Mode
T
Bit191
PH
1
T
PH
PROGRAMMING WAVEFORMS
VERIFY WAVEFORMS
2
T
T
PBW
WC
T
Bit 0
CLKH
Ack
T
CLKL
Bit 1
T
Bit 2
DS
Bit 0
Beginning of Verify Cycle
T
Bit 3
DH
Bit 1 Bit 2
T
Repeat for each word (12 times)
DV
Bit 14
Data from Word 0
Bit 3
Bit 15
T
Write Cycle
Complete Here
CLKL
Twc. After every 16-bit word is written to the HCS201,
the HCS201 will signal that the write is complete by
sending out a train of ACK pulses, T
low (if the oscillator was perfectly tuned) on DATA.
These will continue until S2 is dropped. The first pulse’s
width should NOT be used for calibration. At the end of
the programming cycle, the device can be verified
(Figure 6-2) by reading back the EEPROM. Reading is
done by clocking the S2 line and reading the data bits
on DATA. For security reasons, it is not possible to exe-
cute a verify function without first programming the
EEPROM. A Verify operation can only be done
once, immediately following the Program cycle.
T
Note:
WC
Initiate Data
Polling Here
Bit 14
Ack
To ensure that the device does not acci-
dentally enter Programming mode, DATA
should never be pulled high by the circuit
connected to it. Special care should be
taken when driving PNP RF transistors.
Bit 15
Calibration Pulses
Ack
Bit 16 Bit 17
Ack
HCS201
DS41098C-page 13
ACKH
Bit190 Bit191
Bit 16
Data for Word 1
high, T
Bit 17
ACKL