- 您现在的位置：买卖IC网 > PDF目录11785 > DS80C411-FNY+ (Maxim Integrated Products)IC MCU 75MHZ 16MB HP 100-LQFP PDF资料下载
参数资料
| 型号： | DS80C411-FNY+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 101/102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 Obsolescence Mitigation Program |
| 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： | 64K 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 |
第1页第2页第3页第4页第5页第6页第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页第44页第45页第46页第47页第48页第49页第50页第51页第52页第53页第54页第55页第56页第57页第58页第59页第60页第61页第62页第63页第64页第65页第66页第67页第68页第69页第70页第71页第72页第73页第74页第75页第76页第77页第78页第79页第80页第81页第82页第83页第84页第85页第86页第87页第88页第89页第90页第91页第92页第93页第94页第95页第96页第97页第98页第99页第100页当前第101页第102页
DS80C410/DS80C411 Network Microcontrollers with Ethernet and CAN
98 of 102
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 21. 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 |
|---|---|
| MS27468T17B55PA | CONN RCPT 55POS JAM NUT W/PINS |
| DS87C520-MNL+ | IC MCU EPROM/ROM 33MH IND 40-DIP |
| DS87C530-QCL+ | IC MCU EPR/ROM W/RTC 33MZ 52PLCC |
| DS80C320-MCL+ | IC MCU HI SPEED 33MHZ 40-DIP |
| MS27513E18B35S | CONN RCPT 66POS BOX MNT W/SCKT |
相关代理商/技术参数 |
参数描述 |
|---|---|
| DS80C411-FNY+ | 功能描述:8位微控制器 -MCU Network MCU w/Ethernet & CAN 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 |
| DS80CH11 | 制造商:DALLAS 制造商全称:Dallas Semiconductor 功能描述:System Energy Manager |
| DS80CH11+E02 | 制造商:Maxim from Components Direct 功能描述:MAXIM DS80CH11+E02 SYSTEM ENERGY MANAGERS - Trays 制造商:Maxim 功能描述:Maxim DS80CH11+E02 System Energy Managers |
| DS80CH11-E02 | 制造商:Maxim from Components Direct 功能描述:MAXIM DS80CH11-E02 SYSTEM ENERGY MANAGERS - Trays 制造商:Maxim 功能描述:Maxim DS80CH11-E02 System Energy Managers |
| DS80E100 | 制造商:NSC 制造商全称:National Semiconductor 功能描述:5 to 12.5 Gbps, Power-Saver Equalizer for Backplanes and Cables |
发布紧急采购，3分钟左右您将得到回复。