參數(shù)資料
型號: MC908QY2MDWE
廠商: FREESCALE SEMICONDUCTOR INC
元件分類: 微控制器/微處理器
英文描述: 8-BIT, FLASH, 8 MHz, MICROCONTROLLER, PDSO16
封裝: LEAD FREE, SOIC-16
文件頁數(shù): 170/184頁
文件大?。?/td> 1659K
代理商: MC908QY2MDWE
第1頁第2頁第3頁第4頁第5頁第6頁第7頁第8頁第9頁第10頁第11頁第12頁第13頁第14頁第15頁第16頁第17頁第18頁第19頁第20頁第21頁第22頁第23頁第24頁第25頁第26頁第27頁第28頁第29頁第30頁第31頁第32頁第33頁第34頁第35頁第36頁第37頁第38頁第39頁第40頁第41頁第42頁第43頁第44頁第45頁第46頁第47頁第48頁第49頁第50頁第51頁第52頁第53頁第54頁第55頁第56頁第57頁第58頁第59頁第60頁第61頁第62頁第63頁第64頁第65頁第66頁第67頁第68頁第69頁第70頁第71頁第72頁第73頁第74頁第75頁第76頁第77頁第78頁第79頁第80頁第81頁第82頁第83頁第84頁第85頁第86頁第87頁第88頁第89頁第90頁第91頁第92頁第93頁第94頁第95頁第96頁第97頁第98頁第99頁第100頁第101頁第102頁第103頁第104頁第105頁第106頁第107頁第108頁第109頁第110頁第111頁第112頁第113頁第114頁第115頁第116頁第117頁第118頁第119頁第120頁第121頁第122頁第123頁第124頁第125頁第126頁第127頁第128頁第129頁第130頁第131頁第132頁第133頁第134頁第135頁第136頁第137頁第138頁第139頁第140頁第141頁第142頁第143頁第144頁第145頁第146頁第147頁第148頁第149頁第150頁第151頁第152頁第153頁第154頁第155頁第156頁第157頁第158頁第159頁第160頁第161頁第162頁第163頁第164頁第165頁第166頁第167頁第168頁第169頁當前第170頁第171頁第172頁第173頁第174頁第175頁第176頁第177頁第178頁第179頁第180頁第181頁第182頁第183頁第184頁
Low-Voltage Inhibit (LVI)
MC68HC908QY/QT Family Data Sheet, Rev. 6
86
Freescale Semiconductor
VTRIPF. Setting the LVI enable in stop mode bit, LVISTOP, enables the LVI to operate in stop mode.
Setting the LVI 5-V or 3-V trip point bit, LVI5OR3, enables the trip point voltage, VTRIPF, to be configured
for 5-V operation. Clearing the LVI5OR3 bit enables the trip point voltage, VTRIPF, to be configured for 3-V
operation. The actual trip thresholds are specified in 16.5 5-V DC Electrical Characteristics and 16.9 3-V
NOTE
After a power-on reset, the LVI’s default mode of operation is 3 volts. If a
5-V system is used, the user must set the LVI5OR3 bit to raise the trip point
to 5-V operation.
If the user requires 5-V mode and sets the LVI5OR3 bit after power-on reset
while the VDD supply is not above the VTRIPR for 5-V mode, the
microcontroller unit (MCU) will immediately go into reset. The next time the
LVI releases the reset, the supply will be above the VTRIPR for 5-V mode.
Once an LVI reset occurs, the MCU remains in reset until VDD rises above a voltage, VTRIPR, which
causes the MCU to exit reset. See Chapter 13 System Integration Module (SIM) for the reset recovery
sequence.
The output of the comparator controls the state of the LVIOUT flag in the LVI status register (LVISR) and
can be used for polling LVI operation when the LVI reset is disabled.
10.3.1 Polled LVI Operation
In applications that can operate at VDD levels below the VTRIPF level, software can monitor VDD by polling
the LVIOUT bit. In the configuration register, the LVIPWRD bit must be cleared to enable the LVI module,
and the LVIRSTD bit must be at set to disable LVI resets.
10.3.2 Forced Reset Operation
In applications that require VDD to remain above the VTRIPF level, enabling LVI resets allows the LVI
module to reset the MCU when VDD falls below the VTRIPF level. In the configuration register, the
LVIPWRD and LVIRSTD bits must be cleared to enable the LVI module and to enable LVI resets.
10.3.3 Voltage Hysteresis Protection
Once the LVI has triggered (by having VDD fall below VTRIPF), the LVI will maintain a reset condition until
VDD rises above the rising trip point voltage, VTRIPR. This prevents a condition in which the MCU is
continually entering and exiting reset if VDD is approximately equal to VTRIPF. VTRIPR is greater than
VTRIPF by the hysteresis voltage, VHYS.
10.3.4 LVI Trip Selection
The LVI5OR3 bit in the configuration register selects whether the LVI is configured for 5-V or 3-V
protection.
NOTE
The microcontroller is guaranteed to operate at a minimum supply voltage.
The trip point (VTRIPF [5 V] or VTRIPF [3 V]) may be lower than this.
Characteristics for the actual trip point voltages.
相關(guān)PDF資料
PDF描述
MC908QT4CFQE 8-BIT, FLASH, 8 MHz, MICROCONTROLLER, PDSO8
MC908QY1MDTE 8-BIT, FLASH, 8 MHz, MICROCONTROLLER, PDSO16
MC908QT1CDWE 8-BIT, FLASH, 8 MHz, MICROCONTROLLER, PDSO8
MC908QT2MFQE 8-BIT, FLASH, 8 MHz, MICROCONTROLLER, PDSO8
MC908QY4VDTE 8-BIT, FLASH, 8 MHz, MICROCONTROLLER, PDSO16
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MC908QY2MFQE 制造商:FREESCALE 制造商全稱:Freescale Semiconductor, Inc 功能描述:M68HC08 Microcontrollers
MC908QY2MPE 制造商:FREESCALE 制造商全稱:Freescale Semiconductor, Inc 功能描述:M68HC08 Microcontrollers
MC908QY2PE 制造商:FREESCALE 制造商全稱:Freescale Semiconductor, Inc 功能描述:M68HC08 Microcontrollers
MC908QY2VDTE 制造商:FREESCALE 制造商全稱:Freescale Semiconductor, Inc 功能描述:M68HC08 Microcontrollers
MC908QY2VDWE 制造商:FREESCALE 制造商全稱:Freescale Semiconductor, Inc 功能描述:M68HC08 Microcontrollers