-
The CAT93C46 is a 1 kb Serial EEPROM memory device which isconfigured as either 64 registers of 16 bits (ORG pin at VCC) or 128registers of 8 bits (ORG pin at GND). Each register can be written (orread) serially by using the DI (or DO) pin. The CAT93C46 features aself−timed internal write with auto−clear. On−chip Power−On Resetcircuit protects the internal logic against powering up in the wrongstate.
標簽：
CAT
93C
C46
93
上傳時間：
2013-11-20
上傳用戶：ynzfm
-
Bootloader是微處理器上電時運行的第一段代碼，它可以通過通信接口實現(xiàn)對微處理器內(nèi)部應(yīng)用程序的更新升級，為網(wǎng)絡(luò)化嵌入式產(chǎn)品的應(yīng)用程序升級帶來極大的便利。由于目前沒有統(tǒng)一嵌入式系統(tǒng)的Bootloader。基于NEC 78K0系列單片機自編程原理，設(shè)計出一個適用于78K0/Fx2系列單片機的Bootloader，并能夠通過單片機串口在線升級應(yīng)用程序。
Abstract:
Bootloader is the first piece of code executed after microprocessor startup. It makes the embedded product’s firmware update conveniently through communication interface. However， no unified bootloader is available for all kinds of microprocessor products. Based on the principle of self-programming NEC 78K0s’ series， a useful Bootloader which is suitable for 78K0/Fx2s’ series MCU is designed，the design can update the application through serial ports.
標簽：
Bootloader
MCU
自編程
上傳時間：
2013-10-26
上傳用戶：fang2010
-
The bootloader is stored in the internal boot ROM memory (system memory) of STM32devices. It is programmed by ST during production. Its main task is to download theapplication program to the internal Flash memory through one of the available serialperipherals (USART, CAN, USB, etc.). A communication protocol is defined for each serialinterface, with a compatible command set and sequences
標簽：
STM
32
啟動代碼
上傳時間：
2014-09-06
上傳用戶：417313137
-
The CAT28LV64 is a low voltage, low power, CMOS Parallel EEPROM organized as 8K x 8−bits. It requires a simple interface for in−system programming. On−chip address and data latches, self−timed write cycle with auto−clear and VCC power up/down write protection eliminate additional timing and protection hardware. DATA Polling and Toggle status bit signal the start and end of the self−timed write cycle. Additionally, the CAT28LV64 features hardware and software write protection.
標簽：
EEPROM
64
CMOS
CAT
上傳時間：
2013-11-16
上傳用戶：浩子GG
-
All inputs of the C16x family have Schmitt-Trigger input characteristics. These Schmitt-Triggers are intended to always provide proper internal low and high levels, even if anundefined voltage level (between TTL-VIL and TTL-VIH) is externally applied to the pin.The hysteresis of these inputs, however, is very small, and can not be properly used in anapplication to suppress signal noise, and to shape slow rising/falling input transitions.Thus, it must be taken care that rising/falling input signals pass the undefined area of theTTL-specification between VIL and VIH with a sufficient rise/fall time, as generally usualand specified for TTL components (e.g. 74LS series: gates 1V/us, clock inputs 20V/us).The effect of the implemented Schmitt-Trigger is that even if the input signal remains inthe undefined area, well defined low/high levels are generated internally. Note that allinput signals are evaluated at specific sample points (depending on the input and theperipheral function connected to it), at that signal transitions are detected if twoconsecutive samples show different levels. Thus, only the current level of an input signalat these sample points is relevant, that means, the necessary rise/fall times of the inputsignal is only dependant on the sample rate, that is the distance in time between twoconsecutive evaluation time points. If an input signal, for instance, is sampled throughsoftware every 10us, it is irrelevant, which input level would be seen between thesamples. Thus, it would be allowable for the signal to take 10us to pass through theundefined area. Due to the sample rate of 10us, it is assured that only one sample canoccur while the signal is within the undefined area, and no incorrect transition will bedetected. For inputs which are connected to a peripheral function, e.g. capture inputs, thesample rate is determined by the clock cycle of the peripheral unit. In the case of theCAPCOM unit this means a sample rate of 400ns @ 20MHz CPU clock. This requiresinput signals to pass through the undefined area within these 400ns in order to avoidmultiple capture events.For input signals, which do not provide the required rise/fall times, external circuitry mustbe used to shape the signal transitions.In the attached diagram, the effect of the sample rate is shown. The numbers 1 to 5 in thediagram represent possible sample points. Waveform a) shows the result if the inputsignal transition time through the undefined TTL-level area is less than the time distancebetween the sample points (sampling at 1, 2, 3, and 4). Waveform b) can be the result ifthe sampling is performed more than once within the undefined area (sampling at 1, 2, 5,3, and 4).Sample points:1. Evaluation of the signal clearly results in a low level2. Either a low or a high level can be sampled here. If low is sampled, no transition willbe detected. If the sample results in a high level, a transition is detected, and anappropriate action (e.g. capture) might take place.3. Evaluation here clearly results in a high level. If the previous sample 2) had alreadydetected a high, there is no change. If the previous sample 2) showed a low, atransition from low to high is detected now.
標簽：
Signal
Input
Fall
Rise
上傳時間：
2013-10-23
上傳用戶：copu
-
All inputs of the C16x family have Schmitt-Trigger input characteristics. These Schmitt-Triggers are intended to always provide proper internal low and high levels, even if anundefined voltage level (between TTL-VIL and TTL-VIH) is externally applied to the pin.The hysteresis of these inputs, however, is very small, and can not be properly used in anapplication to suppress signal noise, and to shape slow rising/falling input transitions.Thus, it must be taken care that rising/falling input signals pass the undefined area of theTTL-specification between VIL and VIH with a sufficient rise/fall time, as generally usualand specified for TTL components (e.g. 74LS series: gates 1V/us, clock inputs 20V/us).The effect of the implemented Schmitt-Trigger is that even if the input signal remains inthe undefined area, well defined low/high levels are generated internally. Note that allinput signals are evaluated at specific sample points (depending on the input and theperipheral function connected to it), at that signal transitions are detected if twoconsecutive samples show different levels. Thus, only the current level of an input signalat these sample points is relevant, that means, the necessary rise/fall times of the inputsignal is only dependant on the sample rate, that is the distance in time between twoconsecutive evaluation time points. If an input signal, for instance, is sampled throughsoftware every 10us, it is irrelevant, which input level would be seen between thesamples. Thus, it would be allowable for the signal to take 10us to pass through theundefined area. Due to the sample rate of 10us, it is assured that only one sample canoccur while the signal is within the undefined area, and no incorrect transition will bedetected. For inputs which are connected to a peripheral function, e.g. capture inputs, thesample rate is determined by the clock cycle of the peripheral unit. In the case of theCAPCOM unit this means a sample rate of 400ns @ 20MHz CPU clock. This requiresinput signals to pass through the undefined area within these 400ns in order to avoidmultiple capture events.
標簽：
C16x
微控制器
輸入信號
時序圖
上傳時間：
2014-04-02
上傳用戶：han_zh
-
I2C interface, is a very powerful tool for system designers. Theintegrated protocols allow systems to be completely software defined.Software development time of different products can be reduced byassembling a library of reusable software modules. In addition, themultimaster capability allows rapid testing and alignment ofend-products via external connections to an assembly-line computer.The mask programmable 87LPC76X and its EPROM version, the87LPC76X, can operate as a master or a slave device on the I2Csmall area network. In addition to the efficient interface to thededicated function ICs in the I2C family, the on-board interfacefacilities I/O and RAM expansion, access to EEPROM andprocessor-to-processor communications.
標簽：
microcontro
Using
76X
LPC
上傳時間：
2013-12-30
上傳用戶：Artemis
-
The STWD100 watchdog timer circuits are self-contained devices which prevent systemfailures that are caused by certain types of hardware errors (non-responding peripherals,bus contention, etc.) or software errors (bad code jump, code stuck in loop, etc.).The STWD100 watchdog timer has an input, WDI, and an output, WDO (see Figure 2). Theinput is used to clear the internal watchdog timer periodically within the specified timeoutperiod, twd (see Section 3: Watchdog timing). While the system is operating correctly, itperiodically toggles the watchdog input, WDI. If the system fails, the watchdog timer is notreset, a system alert is generated and the watchdog output, WDO, is asserted (seeSection 3: Watchdog timing).The STWD100 circuit also has an enable pin, EN (see Figure 2), which can enable ordisable the watchdog functionality. The EN pin is connected to the internal pull-downresistor. The device is enabled if the EN pin is left floating.
標簽：
3.3
看門狗
芯片
上傳時間：
2013-10-22
上傳用戶：taiyang250072
-
This application note describes how to retrieve user-defined data from Xilinx configurationPROMs (XC18V00 and Platform Flash devices) after the same PROM has configured theFPGA. The method to add user-defined data to the configuration PROM file is also discussed.The reference design described in this application note can be used in any of the followingXilinx FPGA architectures: Spartan™-II, Spartan-IIE, Spartan-3, Virtex™, Virtex-E, Virtex-II,and Virtex-II Pro.
標簽：
XAPP
PROM
694
讀取
上傳時間：
2013-11-11
上傳用戶：zhouli
-
Express Mode uses an 8-bit wide bus path for fast configuration of Xilinx FPGAs. Thisapplication note provides information on how to perform Express configuration specifically forthe Spartan™-XL family. The Express mode signals and their associated timing are defined.The steps of Express configuration are described in detail, followed by detailed instructions thatshow how to implement the configuration circui
標簽：
Spartan-XL
Express
XAPP
FPGA
上傳時間：
2014-12-28
上傳用戶：hewenzhi
