参数资料
型号: DS80C400-FNY
厂商: Maxim Integrated Products
文件页数: 92/97页
文件大小: 0K
描述: IC MCU 75MHZ 16MB HP 100-LQFP
产品培训模块: Lead (SnPb) Finish for COTS
产品变化通告: Product Discontinuation 20/Feb/2012
标准包装: 90
系列: 80C
核心处理器: 8051
芯体尺寸: 8-位
速度: 75MHz
连通性: 1 线,CAN,EBI/EMI,以太网,SIO,UART/USART
外围设备: 电源故障复位,WDT
输入/输出数: 64
程序存储器容量: 64KB(64K x 8)
程序存储器类型: ROM
RAM 容量: 1K x 8
电压 - 电源 (Vcc/Vdd): 1.62 V ~ 3.6 V
振荡器型: 外部
工作温度: -40°C ~ 85°C
封装/外壳: 100-LQFP
包装: 托盘
配用: DS80C400-KIT#-ND - EVAL KIT FOR DS80C400
DS80C400 Network Microcontroller
92 of 97
Changing the System Clock/Machine Cycle Clock Frequency
The microcontroller incorporates a special locking sequence to ensure “glitch-free” switching of the internal clock
signals. All changes to the CD1, CD0 bits must pass through the 10 (divide-by-4) state. For example, to change
from 00 (frequency multiplier) to 11 (PMM), the software must change the bits in the following sequence: 00b =>
10b => 11b. Attempts to switch between invalid states fail, leaving the CD1, CD0 bits unchanged.
The following sequence must be followed when switching to the frequency multiplier as the internal time source.
This sequence can only be performed when the device is in divide-by-4 operation. The steps must be followed in
this order, although it is possible to have other instructions between them. Any deviation from this order causes the
CD1, CD0 bits to remain unchanged. Switching from frequency multiplier to nonmultiplier mode requires no steps
other than the changing of the CD1, CD0 bits.
1) Ensure that the CD1, CD0 bits are set to 10, and the RGMD (EXIF.2) bit = 0.
2) Clear the crystal multiplier enable (CTM) bit.
3) Set the 4X/2X bit to the appropriate state.
4) Set the CTM bit.
5) Poll the CKRDY bit (EXIF.3), waiting until it is set to 1. This takes approximately 65,536 cycles of the external
crystal or clock source.
6) Set CD1, CD0 to 00. The frequency multiplier is engaged on the machine cycle following the write to these bits.
Figure 20. System Clock Control Diagram
Switchback
As an alternative to software changing the CD1 and CD0 clock control bits to exit PMM, the microcontroller
provides hardware alternatives for automatic switchback to standard speed (divide-by-4) operation. When enabled,
the switchback feature allows serial ports and interrupts to automatically switch back from divide-by-1024 (PMM) to
divide-by-4 (standard speed) operation. This feature makes it very convenient to use the PMM in real-time
applications.
The switchback feature is enabled by setting the SFR bit SWB (PMR.5) to a 1. Once it is enabled, and PMM is
selected, two possible events can cause an automatic switchback to divide-by-4 mode. First, if an external interrupt
occurs and is acknowledged, the system clock reverts from PMM to divide-by-4 mode. For example, if INT0 is
enabled and the CPU is not servicing a higher priority interrupt, then switchback occurs on INT0. However, if INT0
is not enabled or the CPU is servicing a higher priority interrupt, then activity on INT0 does not cause switchback to
occur.
A switchback can also occur when an enabled UART detects the start bit, indicating the beginning of an incoming
serial character or when the SBUF register is loaded initiating a serial transmission. Note that a serial character’s
start bit does not generate an interrupt. The interrupt occurs only on reception of a complete serial word. The
automatic switchback on detection of a start bit allows hardware to return to divide-by-4 operation (and the correct
baud rate) in time for a proper serial reception or transmission.
相关PDF资料
PDF描述
DS80C410-FNY+ IC MCU 75MHZ 16MB HP 100-LQFP
DS8102+ IC MODULATOR/DECODER 16-TSSOP
DS8113-JNG+ IC INTERFACE SMART CARD 28-TSSOP
DS8313-RRX+ IC INTERFACE SMART CARD 28-SOIC
DS8500-JND+T&R IC MODEM HART SGL 3.6V 20-TQFN
相关代理商/技术参数
参数描述
DS80C400-FNY+ 功能描述:8位微控制器 -MCU Network MCU 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
DS80C400-KIT 功能描述:EVAL KIT FOR DS80C400 RoHS:否 类别:编程器,开发系统 >> 通用嵌入式开发板和套件(MCU、DSP、FPGA、CPLD等) 系列:- 产品培训模块:Blackfin® Processor Core Architecture Overview Blackfin® Device Drivers Blackfin® Optimizations for Performance and Power Consumption Blackfin® System Services 特色产品:Blackfin? BF50x Series Processors 标准包装:1 系列:Blackfin® 类型:DSP 适用于相关产品:ADSP-BF548 所含物品:板,软件,4x4 键盘,光学拨轮,QVGA 触摸屏 LCD 和 40G 硬盘 配用:ADZS-BFBLUET-EZEXT-ND - EZ-EXTENDER DAUGHTERBOARDADZS-BFLLCD-EZEXT-ND - BOARD EXT LANDSCAP LCD INTERFACE 相关产品:ADSP-BF542BBCZ-4A-ND - IC DSP 16BIT 400MHZ 400CSBGAADSP-BF544MBBCZ-5M-ND - IC DSP 16BIT 533MHZ MDDR 400CBGAADSP-BF542MBBCZ-5M-ND - IC DSP 16BIT 533MHZ MDDR 400CBGAADSP-BF542KBCZ-6A-ND - IC DSP 16BIT 600MHZ 400CSBGAADSP-BF547MBBCZ-5M-ND - IC DSP 16BIT 533MHZ MDDR 400CBGAADSP-BF548BBCZ-5A-ND - IC DSP 16BIT 533MHZ 400CSBGAADSP-BF547BBCZ-5A-ND - IC DSP 16BIT 533MHZ 400CSBGAADSP-BF544BBCZ-5A-ND - IC DSP 16BIT 533MHZ 400CSBGAADSP-BF542BBCZ-5A-ND - IC DSP 16BIT 533MHZ 400CSBGA
DS80C400-KIT# 功能描述:开发板和工具包 - 8051 RoHS:否 制造商:Silicon Labs 产品:Development Kits 工具用于评估:C8051F960, Si7005 核心: 接口类型:USB 工作电源电压:
DS80C410 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:Network Microcontrollers with Ethernet and CAN
DS80C410_09 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:Network Microcontrollers with Ethernet and CAN