MC68HC11E1CFU3 Freescale Semiconductor, MC68HC11E1CFU3 Datasheet - Page 95

• Manufacturer Part Number: MC68HC11E1CFU3
• Manufacturer: Freescale Semiconductor

Specifications of MC68HC11E1CFU3

• Cpu Family: HC11
• Device Core Size: 8b
• Frequency (max): 3MHz
• Interface Type: SCI/SPI
• Program Memory Type: ROMLess
• Program Memory Size: Not Required
• Total Internal Ram Size: 512Byte
• # I/os (max): 38
• Number Of Timers - General Purpose: 8
• Operating Supply Voltage (typ): 3.3/5V
• Operating Supply Voltage (max): 5.5V
• Operating Supply Voltage (min): 3V
• On-chip Adc: 8-chx8-bit
• Instruction Set Architecture: CISC
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 64
• Package Type: PQFP
• Lead Free Status / Rohs Status: Not Compliant

5.6.2 Stop Mode
Executing the STOP instruction while the S bit in the CCR is equal to 0 places the MCU in stop mode. If
the S bit is not 0, the stop opcode is treated as a no-op (NOP). Stop mode offers minimum power
consumption because all clocks, including the crystal oscillator, are stopped while in this mode. To exit
stop and resume normal processing, a logic low level must be applied to one of the external interrupts
(IRQ or XIRQ) or to the RESET pin. A pending edge-triggered IRQ can also bring the CPU out of stop.
Because all clocks are stopped in this mode, all internal peripheral functions also stop. The data in the
internal RAM is retained as long as V
and are unchanged by stop. Therefore, when an interrupt comes to restart the system, the MCU resumes
processing as if there were no interruption. If reset is used to restart the system, a normal reset sequence
results in which all I/O pins and functions are also restored to their initial states.
To use the IRQ pin as a means of recovering from stop, the I bit in the CCR must be clear (IRQ not
masked). The XIRQ pin can be used to wake up the MCU from stop regardless of the state of the X bit in
the CCR, although the recovery sequence depends on the state of the X bit. If X is set to 0 (XIRQ not
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VALID SCI REQUEST
RDRF = 1?
TDRE = 1?
IDLE = 1?
OR = 1?
TC = 1?
BEGIN
FLAG
N
N
N
N
N
NO
Figure 5-7. Interrupt Source Resolution Within SCI
Y
Y
Y
Y
Y
M68HC11E Family Data Sheet, Rev. 5.1
DD
power is maintained. The CPU state and I/O pin levels are static
ILIE = 1?
RIE = 1?
TIE = 1?
N
N
N
Y
Y
Y
TCIE = 1?
RE = 1?
RE = 1?
TE = 1?
N
N
N
N
VALID SCI REQUEST
Y
Y
Y
Y
Low-Power Operation
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