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參數(shù)資料
| 型號(hào)： | DS87C550 |
| 廠商： | Maxim Integrated Products, Inc. |
| 英文描述： | EPROM High-Speed Micro with A/D and PWM(帶 A/D 和 PWM的EPROM/ROM高速微控制器) |
| 中文描述： | 存儲(chǔ)器高速微與A / D及PWM（帶A / D轉(zhuǎn)換和脈寬調(diào)制的存儲(chǔ)器/ ROM的高速微控制器） |
| 文件頁數(shù)： | 2/27頁 |
| 文件大小： | 119K |
| 代理商： | DS87C550 |
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APPLICATION NOTE 78
030998 2/27
serial ports. Traditional 8051–based devices without the
switchback feature lose the ability to service interrupts
quickly without running the device at high speed, and
higher power consumption, constantly.
SELECTABLE CLOCK SOURCE
The crystal oscillator is a large consumer of power on
any microcontroller, especially during low power opera-
tion. The DS87C5x0 ring oscillator, used for quick starts
from Stop mode, can also be used to provide an approxi-
mately 3 to 4 MHz clock source during normal operation.
Although a crystal oscillator is still required at power–up,
once the crystal has stabilized, device operation can be
switched to the ring oscillator, realizing a power savings
of as much as 25 mA.
BAND–GAP REFERENCE DISABLING
The DS87C5x0 gives the user the option of disabling the
band–gap reference, which is used to detect a power
failure while in Stop mode. Stop mode current can be
reduced from 80
μ
A to 1
μ
A by using this feature.
ENHANCED STATUS REPORTING
Although the ability to dynamically switch the internal
clock speed is a benefit, if performed at the wrong time it
can seriously interfere with the operation of timing–de-
pendent functions. The Status register (STATUS;C5h),
new to the DS87C5x0 devices, contains information
about the status of both serial ports, the crystal oscilla-
tor, and high priority, low priority, and power fail inter-
rupts. The software can delay or cancel a planned
speed change based on the information in this register.
CLOCK SPEED CONTROL
Description
The operating frequency of a microcontroller is the
single biggest factor in determining power consumption.
The DS87C5x0 family of microcontrollers supports four
clock speed management modes which conserve
power by slowing or stopping the internal clock. These
modes allow the system designer to maximize power
savings with a minimum impact on performance.
PMM1
Power Management Mode 1 (PMM1) allows the user to
run the DS87C5x0 at a reduced speed to save power.
Setting the clock divider rate bits (PMR.7–6) will force
the part from its default 4 clocks per machine cycle
(divide by 4) to 64 clocks per machine cycle (divide by
64). The external crystal continues to operate at full
speed. All peripherals and instructions will operate at
this reduced speed. The DS87C5x0 can resume divide
by 4 operation by setting the appropriate clock divider
rate bits or by utilizing the switchback feature.
PMM2
Power Management Mode 2 (PMM2) allows the user to
run the DS87C5x0 at an even slower speed to improve
power savings. Setting the clock divider rate bits
(PMR.7–6) will force the part from its default 4 clocks per
machine cycle (divide by 4) to 1024 clocks per machine
cycle (divide by 1024). The external crystal continues to
operate at full speed. All peripherals and instructions will
operate at this reduced speed. The DS87C5x0 can
resume full–speed (divide by 4) operation by setting the
appropriate clock divider rate bits or by utilizing the
switchback feature. This mode permits an even greater
power savings over PMM1.
STOP MODE
The Stop mode is the lowest power state available to the
DS87C5x0. It is initiated by setting the Stop bit
(PCON.1). While in this mode the crystal oscillator is
stopped, and all internal clocking, including the Watch-
dog Timer, is halted. The real time clock on the
DS87C530 is unaffected by Stop mode. The Stop mode
is exited by an external interrupt, real–time clock inter-
rupt, an external reset via the RST pin, or a power–on
reset. Each interrupt will cause the device to vector to
the corresponding interrupt routine to resume execu-
tion.
The DS87C5x0 incorporates a ring oscillator to allow for
a fast resumption from Stop mode. This provides an
instantaneously available 4 MHz clock source for the
device to start operation. It can function until the crystal
has stabilized, or can continue to be used as the clock
source. The ring oscillator does not exhibit as much sta-
bility as an external clock, and the device should not per-
form timing measurements requiring high accuracy or
serial port data transfers while operating from the ring
oscillator. For more information concerning the use of
the ring oscillator, please consult the Clock Source Con-
trol section of this document.
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| DS87C550-FCL | 制造商:DALLAS 制造商全稱:Dallas Semiconductor 功能描述:EPROM High-Speed Micro with A/D and PWM |
| DS87C550-FNL | 制造商:DALLAS 制造商全稱:Dallas Semiconductor 功能描述:EPROM High-Speed Micro with A/D and PWM |
| DS87C550-KCL | 制造商:DALLAS 制造商全稱:Dallas Semiconductor 功能描述:EPROM High-Speed Micro with A/D and PWM |
| DS87C550-QCL | 制造商:DALLAS 制造商全稱:Dallas Semiconductor 功能描述:EPROM High-Speed Micro with A/D and PWM |
| DS87C550-QCL+ | 功能描述:IC MCU EPROM ADC/PWM HS 68-PLCC RoHS:是 類別:集成電路 (IC) >> 嵌入式 - 微控制器， 系列:87C 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:260 系列:73S12xx 核心處理器:80515 芯體尺寸:8-位 速度:24MHz 連通性:I²C，智能卡，UART/USART，USB 外圍設(shè)備:LED，POR，WDT 輸入/輸出數(shù):9 程序存儲(chǔ)器容量:64KB（64K x 8） 程序存儲(chǔ)器類型:閃存 EEPROM 大小:- RAM 容量:2K x 8 電壓 - 電源 (Vcc/Vdd):2.7 V ~ 5.5 V 數(shù)據(jù)轉(zhuǎn)換器:- 振蕩器型:內(nèi)部 工作溫度:-40°C ~ 85°C 封裝/外殼:68-VFQFN 裸露焊盤 包裝:管件 |
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