1999-2013 Microchip Technology Inc. Preliminary DS41115D-page 7
HCS101
6.0 PROGRAMMING THE HCS101
When using the HCS101 in a system, the user will have
to program some parameters into the device, including
the serial number and the counter, before it can be
used. The programming cycle allows the user to input
a 192-bit serial data stream which is then stored inter-
nally 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. Refer to
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 all zeros. 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
Twc.
The HCS101 will signal that the write is complete by
sending out a train of ACK pulses, T
ACKH high, TACKL
low on DATA. The ACK pulses will continue until S2 is
dropped. These times can be used to calculate the
oscillator calibration value. The first pulse’s width
should NOT be used for calibration.
At the end of the programming cycle, the device can be
verified as shown in Figure 6-2 by reading back the
EEPROM. Reading is done by clocking the S2 line and
reading the data bits on the DATA pin. A verify opera-
tion can only be done once, immediately following
the program cycle.
FIGURE 6-1: PROGRAMMING WAVEFORMS
FIGURE 6-2: VERIFY WAVEFORMS
Note: 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.
DATA
Enter Program
Mode
(Data)
(Clock)
Note: S0 and S1 button inputs to be held to ground during the entire programming sequence.
Bit 0 Bit 1 Bit 2 Bit 3 Bit 14 Bit 15 Bit 16 Bit 17
TPH1
T
PBW
TPS
Repeat 12 times for each word
TPH2
TCLKH
TCLKL
TWC
TDS
S2
Data for Word 1
TDH
TCLKL
Initiate Data Polling Here
Write Cycle
Complete Here
TACLKL
TACLKH
Calibration Pulses
TPH
O
L
D
DATA
(Clock)
(Data)
Note: If a Verify operation is to be done, then it must immediately follow the Program cycle.
End of
Programming Cycle
Begin Verify Cycle Here
Bit 1 Bit 2 Bit 3 Bit 15
Bit 14
Bit 16 Bit 17 Bit190 Bit191
TWC
Data in Word 0
TDV
S2
Bit 0Bit191Bit190
