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在我的时钟设计中，我用完了PIN。我只在PIC16F628 A中留下了RA4。想通过ULN2003和AMP驱动一个单独的段（小数点），也希望扫描一个按钮。这会像附件那样工作吗？我需要一个带开关的1K电阻吗？谢谢
以上来自于百度翻译 以下为原文 I ran out of pins in my clock design.I left only RA4 in PIC 16F628A.Want to drive a single segment (Decimal Point) via ULN2003 & want to scan a button as well. Will this work as in the attachment?Do I need a series 1K resister with the switch? Thanks Attached Image(s) 
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11个回答
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我假设你知道RA4是一个开路漏极输出，所以ULN2003的所有驱动器都必须来自4.7K电阻。在ULN2003输入上至少需要2V来打开它，所以在电阻上只有3V，所以只有0.63Ma。这可能起作用，但是它正好在不工作的阈值上。G.我建议减少上拉电阻到1K。此外，如果引脚仅在2V，那么当按钮不预设时，您将难以读取它。RA4是ST输入，所以对于高输入，至少需要0.8VDD，当VCC＝5V时是4V。
以上来自于百度翻译 以下为原文 I assume you are aware that RA4 is an open drain output, so all the drive for the ULN2003 has to come from the 4.7k resistor. You need at least 2V on the ULN2003 input to turn it on, so there's only 3V across the resistor, so only 0.63mA. This might work, but it's right on the threshold of not working. I'd suggest reducing the pullup resistor to 1k. Also, if the pin was only at 2V, you'd have trouble reading it as a high when the button is not pressed. RA4 is an ST input, so needs at least 0.8Vdd for a high input, which is 4V when Vcc=5V. |
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让我们看看整个示意图（或者至少是一个方块图，显示所有PIC引脚的使用情况）。可能有更好的选择——例如：将按钮与数字一起复用，这样一个输入可以处理与你的数字一样多的按钮。或者，比较器具有4位电阻DI。VIDER链DAC，它可以用来实现一个4位ADC，读取按钮连接在一个潜在的分配器与下臂组成的电阻链与按钮短路节点到地面。
以上来自于百度翻译 以下为原文 Lets see the whole schematic (or at least a block diagram showing what all the PIC pins are used for. There's probably a better option - e.g:
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2002？它可以追溯到更远的地方——MCUs一开始出现在消费电子产品上，大概是在80年初的某个时候。当然，那时他们没有芯片上的ADC或比较器，但是你可以从I/O引脚充电电容器，然后将PIN设置为输入并让C。AP通过你的电阻梯放电，时间要花多长时间才能变低。
以上来自于百度翻译 以下为原文 2002? It dates back far further than that - as soon as MCUs started appearing in consumer electronics, so probably sometime around the early 80's. Of course back then they didn't have on-chip ADCs or comparators, but you could charge a capacitor from an I/O pin, then set the pin as an input and let the cap discharge through your resistor ladder, and time how long it took to go low. |
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事实上：我的意思是“我在2002的PIC上做的”是的，我开始看到studying ADCs在这些“双斜坡”转换器与原始TTL…我想大概是1977年左右我父亲的杂志。
以上来自于百度翻译 以下为原文 Indeed: I meant "I did it on this PIC in 2002" Yeah I started seeing and studying ADCs on these "dual-ramp" converter made with RAW TTL... I think they were my father's magazines in 1977 or so.. |
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您需要使用哪种类型的7段显示器，需要ULN2003？
以上来自于百度翻译 以下为原文 What type of 7-segment display are you using that requires an ULN2003? |
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嗨，朋友们，谢谢你们的意见。我只是睁开眼睛，深入了解每一个引脚的电压响应水平。嗨，我想我已经附上了真正的原理图。在PCB上，组件安装在与示意图相同的位置，以减少跳线。我有12V四公共阳极段DI。由LED制成的GIT。时间由RTC & AMP读取，只显示四段。我只有小时调整按钮，我需要另一分钟调整按钮，但是没有找到针的地方：
以上来自于百度翻译 以下为原文 Hi friends thanks for your view.I just opened my eyes deeper into voltage response levels at each pins. Hi IanM Excellant thinking.I have attached the real schematic.On the PCB, components are mounted in the same position as in the schematic to minimize jumpers. I have 12V four common anode segment digits made by LEDs.Time is read by RTC & just show on four segments. I have only hour adjustments button,I need another minute adjustment button,but no place to find a pin :( Attached Image(s) |
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这很容易。将按钮移到地上，将下拉改变为下拉并连接多达四个按钮，每个按钮在RA5和一个数字驱动线之间串联一个二极管。二极管阴极朝向RA5。当对齐数字线高时，可以在RA5上读取它的按钮。最好在每个复用接口结束时，在您改变数字选择线之前。
以上来自于百度翻译 以下为原文 That's easy. Remove the button to ground, change the pullup to a pulldown and connect up to four buttons, each with a series diode between RA5 and one of the digit drive lines. Diode cathode towards RA5. When the corisponding digit line is high, its button can be read on RA5. Its best to do so at the end of each multiplexing intterval just before you change the digit select lines. |
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我从你的建议中设法完成了我的最后一个PCB.HTTPS://Dr.GoGoLe.COM/FIL/D/0B3RelHopHPVPVZEFVTMNNE3VUK/VIEW？谢谢你的帮助，你是最好的…
以上来自于百度翻译 以下为原文 Wonderful information.From your suggession I managed to do my final PCB. https://drive.google.com/file/d/0B3RELHoBhPvpZEFvTmNnNER3VUk/view?usp=sharing Thank you very much for the help.You are best here... |
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HII在这个设计上有一个小的验证。当LED七个灯点亮时，它会释放1000μF的储能电容器，并产生一个纹波到7805个调节器。这会影响DS1307的准确度吗？多年来，我一直在努力获得一个真正准确的时间与这个设计和失败。添加了一个平方输入，精度提高了一点和需要调整我的硬件设计/ PCB /去耦材料。我只有一个0.1UF解耦帽附近的调节器和10UF附近的DS1307。够了吗？我还需要一个靠近水晶的地面飞机吗？HTTPS://Dr.GoGoLe.COM/FIL/D/0B3RelHopHPVPVZEFVTMNNE3VUK/VIEW？USP =共享
以上来自于百度翻译 以下为原文 Hi I have a small verification on this design. When the LED seven segments lights up, it will discharge the 1000uF reservoir capacitor & generates a ripple to the 7805 regulator.Will this effect the accuracy to DS1307? Over the years I have struggled to get a real accurate time with this design & failed.After adding a SQW input the accuracy improved a bit & needs to fine tune my hardware design/PCB/decoupling stuff. I have only one 0.1uF decoupling cap near the regulator & a 10uF near the DS1307.Is this enough? Also Do I need a groundplane near the crystal as well? https://drive.google.com/file/d/0B3RELHoBhPvpZEFvTmNnNER3VUk/view?usp=sharing Attached Image(s) |
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我认为，一点涟漪不应该改变RTC精度。当然，如果你能使“形势”更好…它会喜欢它通常0.1UF必须放置在靠近电源引脚（否则，他们的目标在更高的频率将被击败），而电解可以“任何地方”。克里斯蒂尔总是喜欢一些屏蔽IMO。
以上来自于百度翻译 以下为原文 I'd say that a bit of ripple should not alter RTC precision. Sure if you can make the "situation" better... it will like it Usually 0.1uF must be placed close to the power pins (otherwise their goal at higher frequencies would be defeated) while electrolyitcs can go "anywhere". A cristal will always like some shielding IMO |
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