MC68HC711E20CFN2 Freescale Semiconductor, MC68HC711E20CFN2 Datasheet - Page 34

• Manufacturer Part Number: MC68HC711E20CFN2
• Description: IC MCU 20K 2MHZ OTP 52-PLCC
• Manufacturer: Freescale Semiconductor
• Series: HC11r

Specifications of MC68HC711E20CFN2

• Core Processor: HC11
• Core Size: 8-Bit
• Speed: 2MHz
• Connectivity: SCI, SPI
• Peripherals: POR, WDT
• Number Of I /o: 38
• Program Memory Size: 20KB (20K x 8)
• Program Memory Type: OTP
• Eeprom Size: 512 x 8
• Ram Size: 768 x 8
• Voltage - Supply (vcc/vdd): 4.5 V ~ 5.5 V
• Data Converters: A/D 8x8b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 52-PLCC
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Pin Descriptions
2.4 RESET
Technical Data
34
CAUTION:
A bidirectional control signal, RESET, acts as an input to initialize the
MCU to a known startup state. It also acts as an open-drain output to
indicate that an internal failure has been detected in either the clock
monitor or computer operating properly (COP) watchdog circuit. The
CPU distinguishes between internal and external reset conditions by
sensing whether the reset pin rises to a logic 1 in less than two E-clock
cycles after a reset has occurred. See
Do not connect an external resistor capacitor (RC) power-up delay
circuit to the reset pin of M68HC11 devices because the circuit charge
time constant can cause the device to misinterpret the type of reset that
occurred.
Because the CPU is not able to fetch and execute instructions properly
when V
be controlled. A low-voltage inhibit (LVI) circuit is required primarily for
protection of EEPROM contents. However, since the configuration
register (CONFIG) value is read from the EEPROM, protection is
required even if the EEPROM array is not being used.
Presently, there are several economical ways to solve this problem. For
example, two good external components for LVI reset are:
Refer to
1. The Seiko S0854HN (or other S805 series devices):
2. The Motorola MC34064:
— Extremely low power (2 A)
— TO-92 package
— Limited temperature range, –20 C to +70 C
— Available in various trip-point voltage ranges
— TO-92 or SO-8 package
— Draws about 300 A
— Temperature range –40 C to 85 C
— Well controlled trip point
— Inexpensive
DD
Section 5. Resets and Interrupts
falls below the minimum operating voltage level, reset must
Pin Descriptions
Figure 2-6
for further information.
M68HC11E Family — Rev. 3.2
and
Figure
MOTOROLA
2-7.