MC68HC908QT2CPE Freescale, MC68HC908QT2CPE Datasheet - Page 106

• Manufacturer Part Number: MC68HC908QT2CPE
• Manufacturer: Freescale

Specifications of MC68HC908QT2CPE

• Cpu Family: HC08
• Device Core Size: 8b
• Frequency (max): 8MHz
• Total Internal Ram Size: 128Byte
• # I/os (max): 6
• Number Of Timers - General Purpose: 2
• Operating Supply Voltage (typ): 3.3/5V
• Operating Supply Voltage (max): 5.5V
• Operating Supply Voltage (min): 2.7V
• On-chip Adc: 4-chx8-bit
• Instruction Set Architecture: CISC
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Through Hole
• Pin Count: 8
• Package Type: PDIP
• Program Memory Type: Flash
• Program Memory Size: 1.5KB
• Lead Free Status / RoHS Status: Compliant

System Integration Module (SIM)
13.4.1 External Pin Reset
The RST pin circuits include an internal pullup device. Pulling the asynchronous RST pin low halts all
processing. The PIN bit of the SIM reset status register (SRSR) is set as long as RST is held low for at
least the minimum t
if the RSTEN bit is set in the CONFIG2 register.
13.4.2 Active Resets from Internal Sources
The RST pin is initially setup as a general-purpose input after a POR. Setting the RSTEN bit in the
CONFIG2 register enables the pin for the reset function. This section assumes the RSTEN bit is set when
describing activity on the RST pin.
The active reset feature allows the part to issue a reset to peripherals and other chips within a system
built around the MCU.
All internal reset sources actively pull the RST pin low for 32 BUSCLKX4 cycles to allow resetting of
external peripherals. The internal reset signal IRST continues to be asserted for an additional 32 cycles
(see
LVI, or POR (see
106
Figure
13-4). An internal reset can be caused by an illegal address, illegal opcode, COP time out,
BUSCLKX4
ADDRESS BUS
ADDRESS
For POR and LVI resets, the SIM cycles through 4096 BUSCLKX4 cycles
during which the SIM forces the RST pin low. The internal reset signal then
follows the sequence from the falling edge of RST shown in
The COP reset is asynchronous to the bus clock.
BUSCLKX2
IRST
RST
BUS
Figure
RL
RST
time.
13-5).
PC
Figure 13-3
RST PULLED LOW BY MCU
MC68HC908QY/QT Family Data Sheet, Rev. 6
Figure 13-3. External Reset Timing
Figure 13-4. Internal Reset Timing
shows the relative timing. The RST pin function is only available
32 CYCLES
NOTE
32 CYCLES
VECT H VECT L
Figure
VECTOR HIGH
13-4.
Freescale Semiconductor