參數(shù)資料
型號(hào): MC68HC11D3CP1
廠商: ABILIS SYSTEMS
元件分類: 微控制器/微處理器
英文描述: 8-BIT, MROM, 1 MHz, MICROCONTROLLER, PDIP40
封裝: PLASTIC, DIP-40
文件頁(yè)數(shù): 65/124頁(yè)
文件大?。?/td> 6875K
代理商: MC68HC11D3CP1
第1頁(yè)第2頁(yè)第3頁(yè)第4頁(yè)第5頁(yè)第6頁(yè)第7頁(yè)第8頁(yè)第9頁(yè)第10頁(yè)第11頁(yè)第12頁(yè)第13頁(yè)第14頁(yè)第15頁(yè)第16頁(yè)第17頁(yè)第18頁(yè)第19頁(yè)第20頁(yè)第21頁(yè)第22頁(yè)第23頁(yè)第24頁(yè)第25頁(yè)第26頁(yè)第27頁(yè)第28頁(yè)第29頁(yè)第30頁(yè)第31頁(yè)第32頁(yè)第33頁(yè)第34頁(yè)第35頁(yè)第36頁(yè)第37頁(yè)第38頁(yè)第39頁(yè)第40頁(yè)第41頁(yè)第42頁(yè)第43頁(yè)第44頁(yè)第45頁(yè)第46頁(yè)第47頁(yè)第48頁(yè)第49頁(yè)第50頁(yè)第51頁(yè)第52頁(yè)第53頁(yè)第54頁(yè)第55頁(yè)第56頁(yè)第57頁(yè)第58頁(yè)第59頁(yè)第60頁(yè)第61頁(yè)第62頁(yè)第63頁(yè)第64頁(yè)當(dāng)前第65頁(yè)第66頁(yè)第67頁(yè)第68頁(yè)第69頁(yè)第70頁(yè)第71頁(yè)第72頁(yè)第73頁(yè)第74頁(yè)第75頁(yè)第76頁(yè)第77頁(yè)第78頁(yè)第79頁(yè)第80頁(yè)第81頁(yè)第82頁(yè)第83頁(yè)第84頁(yè)第85頁(yè)第86頁(yè)第87頁(yè)第88頁(yè)第89頁(yè)第90頁(yè)第91頁(yè)第92頁(yè)第93頁(yè)第94頁(yè)第95頁(yè)第96頁(yè)第97頁(yè)第98頁(yè)第99頁(yè)第100頁(yè)第101頁(yè)第102頁(yè)第103頁(yè)第104頁(yè)第105頁(yè)第106頁(yè)第107頁(yè)第108頁(yè)第109頁(yè)第110頁(yè)第111頁(yè)第112頁(yè)第113頁(yè)第114頁(yè)第115頁(yè)第116頁(yè)第117頁(yè)第118頁(yè)第119頁(yè)第120頁(yè)第121頁(yè)第122頁(yè)第123頁(yè)第124頁(yè)
RESETS AND INTERRUPTS
TECHNICAL DATA
5-1
SECTION 5
RESETS AND INTERRUPTS
Resets and interrupt operations load the program counter with a vector that points to
a new location from which instructions are to be fetched. A reset immediately stops
execution of the current instruction and forces the program counter to a known starting
address. Internal registers and control bits are initialized so the MCU can resume ex-
ecuting instructions. An interrupt temporarily suspends normal program execution
while an interrupt service routine is being executed. After an interrupt has been ser-
viced, the main program resumes as if there had been no interruption.
5.1 Resets
There are four possible sources of reset. Power-on reset (POR) and external reset
share the normal reset vector. The computer operating properly (COP) system and the
clock monitor each has its own vector.
5.1.1 Power-On Reset
A positive transition on VDD generates a power-on reset (POR), which is used only for
power-up conditions. POR cannot be used to detect drops in power supply voltages.
A 4064 tCYC (internal clock cycle) delay after the oscillator becomes active allows the
clock generator to stabilize. If RESET is at logical zero at the end of 4064 tCYC, the
CPU remains in the reset condition until goes to logical one.
It is important to protect the MCU during power transitions. Most M68HC11 systems
need an external circuit that holds the RESET pin low whenever VDD is below the min-
imum operating level. This external voltage level detector, or other external reset cir-
cuits, are the usual source of reset in a system. The POR circuit only initializes internal
circuitry during cold starts. Refer to Figure 2-3.
5.1.2 External Reset (RESET)
The CPU distinguishes between internal and external reset conditions by sensing
whether the reset pin rises to a logic one in less than two E-clock cycles after an inter-
nal device releases reset. When a reset condition is sensed, the RESET pin is driven
low by an internal device for four E-clock cycles, then released. Two E-clock cycles
later it is sampled. If the pin is still held low, the CPU assumes that an external reset
has occurred. If the pin is high, it indicates that the reset was initiated internally by ei-
ther the COP system or the clock monitor. It is not advisable to connect an external
resistor capacitor (RC) power-up delay circuit to the reset pin of M68HC11 devices be-
cause the circuit charge time constant can cause the device to misinterpret the type of
reset that occurred.
5.1.3 COP Reset
The MCU includes a COP system to help protect against software failures. When the
F
re
e
sc
a
le
S
e
m
ic
o
n
d
u
c
to
r,
I
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
n
c
..
.
相關(guān)PDF資料
PDF描述
MC68HC11D0CFN3 8-BIT, MROM, 3 MHz, MICROCONTROLLER, PQCC44
MC68HC711D0CFB 8-BIT, OTPROM, 2 MHz, MICROCONTROLLER, PQFP44
MC68HC11D0CP3 8-BIT, MROM, 3 MHz, MICROCONTROLLER, PDIP40
MC68HC711D0CP3 8-BIT, OTPROM, 3 MHz, MICROCONTROLLER, PDIP40
MC68HC11D0CFB3 8-BIT, MROM, 2 MHz, MICROCONTROLLER, PQFP44
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MC68HC11D3FB 制造商:FREESCALE 制造商全稱:Freescale Semiconductor, Inc 功能描述:ROM-based high-performance microcontrollers
MC68HC11D3FB1 制造商:FREESCALE 制造商全稱:Freescale Semiconductor, Inc 功能描述:ROM-based high-performance microcontrollers
MC68HC11D3FB3 制造商:FREESCALE 制造商全稱:Freescale Semiconductor, Inc 功能描述:ROM-based high-performance microcontrollers
MC68HC11D3FB4 制造商:FREESCALE 制造商全稱:Freescale Semiconductor, Inc 功能描述:ROM-based high-performance microcontrollers
MC68HC11D3FN 制造商:FREESCALE 制造商全稱:Freescale Semiconductor, Inc 功能描述:ROM-based high-performance microcontrollers