- 您现在的位置：买卖IC网 > PDF目录97870 > DS87C520-ECL (MAXIM INTEGRATED PRODUCTS INC) 8-BIT, OTPROM, 33 MHz, MICROCONTROLLER, PQFP44 PDF资料下载
参数资料
| 型号： | DS87C520-ECL |
| 厂商： | MAXIM INTEGRATED PRODUCTS INC |
| 元件分类： | Microcontroller |
| 英文描述： | 8-BIT, OTPROM, 33 MHz, MICROCONTROLLER, PQFP44 |
| 封装： | 10 X 10 MM, 1 MM HEIGHT, TQFP-44 |
| 文件页数： | 7/43页 |
| 文件大小： | 709K |
| 代理商： | DS87C520-ECL |
第1页第2页第3页第4页第5页第6页当前第7页第8页第9页第10页第11页第12页第13页第14页第15页第16页第17页第18页第19页第20页第21页第22页第23页第24页第25页第26页第27页第28页第29页第30页第31页第32页第33页第34页第35页第36页第37页第38页第39页第40页第41页第42页第43页
DS87C520/DS83C520 EPROM/ROM High-Speed Microcontrollers
15 of 43
CRYSTAL-LESS PMM
A major component of power consumption in PMM is the crystal amplifier circuit. The
DS87C520/DS83C520 allow the user to switch CPU operation to an internal ring oscillator and turn off
the crystal amplifier. The CPU would then have a clock source of approximately 2MHz to 4MHz, divided
by either 4, 64, or 1024. The ring is not accurate, so software cannot perform precision timing. However,
this mode allows an additional saving of between 0.5mA and 6.0mA, depending on the actual crystal
frequency. While this saving is of little use when running at 4 clocks per instruction cycle, it makes a
major contribution when running in PMM1 or PMM2.
PMM OPERATION
Software invokes the PMM by setting the appropriate bits in the SFR area. The basic choices are divider
speed and clock source. There are three speeds (4, 64, and 1024) and two clock sources (crystal and ring).
Both the decisions and the controls are separate. Software will typically select the clock speed first. Then,
it will perform the switch to ring operation if desired. Lastly, software can disable the crystal amplifier if
desired.
There are two ways of exiting PMM. Software can remove the condition by reversing the procedure that
invoked PMM or hardware can (optionally) remove it. To resume operation at a divide-by-4 rate under
software control, simply select 4 clocks per cycle, then crystal-based operation if relevant. When
disabling the crystal as the time base in favor of the ring oscillator, there are timing restrictions associated
with restarting the crystal operation. Details are described below.
There are three registers containing bits that are concerned with PMM functions. They are Power
Management Register (PMR; C4h), Status (STATUS; C5h), and External Interrupt Flag (EXIF; 91h).
Clock Divider
Software can select the instruction cycle rate by selecting bits CD1 (PMR.7) and CD0 (PMR.6) as
follows:
CD1
CD0
CYCLE RATE
0
Reserved
0
1
4 clocks (default)
1
0
64 clocks
1
1024 clocks
The selection of instruction cycle rate will take effect after a delay of one instruction cycle. Note that the
clock divider choice applies to all functions including timers. Since baud rates are altered, it will be
difficult to conduct serial communication while in PMM. There are minor restrictions on accessing the
clock selection bits. The processor must be running in a 4-clock state to select either 64 (PMM1) or 1024
(PMM2) clocks. This means software cannot go directly from PMM1 to PMM2 or visa versa. It must
return to a 4-clock rate first.
相关PDF资料 |
PDF描述 |
|---|---|
| DS87C520-MNL | 8-BIT, OTPROM, 33 MHz, MICROCONTROLLER, PDIP40 |
| DS87C520-ENL | 8-BIT, OTPROM, 33 MHz, MICROCONTROLLER, PQFP44 |
| DS87C520-WCL | 8-BIT, UVPROM, 33 MHz, MICROCONTROLLER, CDIP40 |
| DS87C530-ENL | 8-BIT, OTPROM, 33 MHz, MICROCONTROLLER, PQFP52 |
| DS87C530-QCL | 8-BIT, OTPROM, 33 MHz, MICROCONTROLLER, PQCC52 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| DS87C520-ECL+ | 功能描述:8位微控制器 -MCU EPROM/ROM High-Speed RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT |
| DS87C520-ENL | 功能描述:8位微控制器 -MCU EPROM/ROM High-Speed RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT |
| DS87C520-ENL+ | 功能描述:8位微控制器 -MCU EPROM/ROM High-Speed RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT |
| DS87C520-FCL | 制造商:未知厂家 制造商全称:未知厂家 功能描述:8-Bit Microcontroller |
| DS87C520MCL | 制造商:DALLAS 制造商全称:Dallas Semiconductor 功能描述:EPROM/ROM High-Speed Microcontrollers |
发布紧急采购，3分钟左右您将得到回复。