The Circuit Designer’s Companion Second edition Tim Williams
标签： Designers Companion Circuit PCB
上传时间： 2013-11-03
上传用户：fredguo
STM32全系列处理器具有脚对脚、外设及软件的高度兼容性。这给应用带来很好的灵活性，易于将应用升级到不同存储空间或不同封装的平台。STM32处理器的产品全系列兼容，使得项目之间的代码重用和移植很方便。
上传时间： 2013-11-12
上传用户：zhengzg
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.
上传时间： 2013-10-23
上传用户：copu
STM32
上传时间： 2013-10-13
上传用户：jdm439922924
STM32
上传时间： 2014-10-30
上传用户：tianyi996
The Circuit Designer’s Companion Second edition Tim Williams
标签： Designers Companion Circuit PCB
上传时间： 2013-10-07
上传用户：sxdtlqqjl
国外游戏开发者杂志2001年第八期配套代码，包含Tim Schoeder在Volition Red Faction使用到的碰撞探测系统源代码
上传时间： 2013-12-21
上传用户：蠢蠢66
K3:--- P1.6 K4:--- P1.7 BEEP:--- P3.7 K3 --- 控制按键 K4 --- 清零按键 开机显示： SECOND-CLOCK 0 TimE 00:00:00:00 K3 --- 控制按键： 第一次按下时,开始计时。 显示 BEGIN COUNT 1 TimE 00:00:01:88 第二次按下时,暂停计时。 显示 PAUST COUNT 2 TimE 00:00:01:88 第三次按下时,累计计时。 显示 BEGIN COUNT 3 TimE 00:08:08:88 第四次按下时,暂停计时。 显示 PAUST COUNT 4 TimE 00:08:08:88 K4 --- 清零按键： 在任何状态下，按一下K4，均可清零。 显示 SECOND-CLOCK 0 TimE 00:00:00:00 0,1,2,3,4 表示按下K3键的次数。
标签： SECOND-CLOCK K3 BEEP K4
上传时间： 2014-01-14
上传用户：515414293
嵌入式系统开发 TOPPERS and JSP Kernel Release 1.3 TOPPERS = Toyohashi Open Platform for Embedded Real-Time Systems JSP = Just Standard Profile Kernel
标签： TOPPERS Toyohashi Embedded Platform
上传时间： 2013-12-26
上传用户：清风冷雨
An example to accompany PCW March 2004 Visual Programming Hands On. To use, open the solution in the SchoolApp folder. April 2004: Now revised to add New and Delete options. Tim Anderson http://www.itwriting.com/pcw/
标签： Programming accompany solution example
上传时间： 2015-12-08
上传用户：qunquan
