MC68HC68T1 Datasheet, PDF (22/26 Pages) Motorola, Inc – Real-Time Clock plus RAM with Serial Interface

CLOCK
BUTTON
IGNITION
ENABLED POWER
+
12 V
–
5V
REG
100 kW
0.1 mF
NOTE 1
11
LINE
16 12
VDD VSYS
13
10 ^VBATT
POR
9
PSE
MC68HC68T1
14 _XTAL
2 MHz
2
CPUR
40
VDD
28
PORT
NOTE 2
MC68HC05C4
1
RESET
15
1
CLKOUT
3
INT
SPI
7
3
VSS
SS
8
39
OSC 1
2
IRQ
SPI
27
PORT VSS
20
NOTES:
1. The VSYS and Line inputs can be used to sense the ignition turning on and off. An external switch is included to activate the
system without turning on the ignition. Also, the CMOS CPU is not powered down with the system VDD, but is held in a low
power reset mode during power–down. When restoring power, the MC68HC68T1 enables the CLKOUT pin and sets the
PSE and CPUR pins high.
2. If an MC68HC11 MCU is used, delete the capacitor at the RESET pin.
3. Voltage at pin must not exceed absolute maximum Vin specification.
Figure 21. Automotive System
MC68HC68T1
22
MOTOROLA