TMS3637 Datasheet, PDF (21/53 Pages) Texas Instruments – Remote Control Transmitter/Receiver

8. After a minimum valid time of t_v = 10 µs, apply the high-voltage programming pulse to
permanently store the 31 code bits in EEPROM memory as shown in Figure 5–2. As stated in
steps 4 and 5, exactly 4 reset and 31 clock pulses must be applied for the device to successfully
program. The device does not transfer the code from its registers into the EEPROM if less than
or greater than 4 reset and 31 clock pulses are used before the programming pulse is applied.
5V
VCC
tsu3
OSCR
(clock in)
tw6
tw7
IN
(data in)
4 Reset Pulses
C01– C22
22 Security Bits
CA– CI
9 Configuration Bits
C01
C03
C22
CI
C02
C04
CA
tv
5V
15 V
OSCC
OUT
(previous data)†
5.5 V
High-Voltage
Programming Pulse
OSCR
(clock)
IN
(data in)
tsu4 > 1 µs
th1 > 1 µs
† _{Previous data refers to data that was previously programmed into the device. If programmed for first time, this contains}
a random test code from the factory.
Figure 5–2. EEPROM Write Mode
5.3 Internal Oscillator Operation for Transmit and Receive Modes Setting
Frequency
The TMS3637 has an internal oscillator that can be used in either the transmit or receive configurations of
the device. The oscillator free-running frequency (f_osc) is controlled by an external resistor and capacitor
and is determined by:
f_osc = 5 / (4 × C_osc × R_osc)
(1)
where
C_osc = capacitor from OSCC to GND
R_osc = resistor from OSCR to GND
The allowable oscillation range or R_osc versus V_CC, and associated f_osc values, and range versus C_osc for
three given values of R_osc are given in Section 4.
5–3