yike | 本项目是仿照微信、QQ开发的即时通讯模块功能。 现完成了： 1 | Socket library

The following error is being prompted when it is tried to add a new cluster in 'CMAK' in the K8s cluster.

Im trying to simulate breathing in a React Native app, the console log of the breathing in breathing out seems to work okay, however the Text never updates on the screen. it just sits on 'IN'

I'm new to react and struggling to find a solution. I tried using useState in stead of useRef for the current breathing status and it still does not update and the console does not work as expected when using useState.

Overview:

I spent a while trying to think of how to formulate this question. To narrow the scope, I wanted to provide my initial HW requirements in the form of a ‘real life’ example application.

I understand that clock speed is probably relative, in the sense that it is a case by case basis. For example, your requirement for a certain speed may be impacted on by the on-chip peripherals offered by the MCU. As an example, you may spend (n) cycles servicing an ISR for an encoder, or, you could pick an MCU that has a QEI input to do it for you (to some degree), which in turn, may loosen your requirement?

I am not an expert, and am very much still learning, so please call me out if I use an incorrect term, or completely misinterpret something. I assure you; the feedback is welcome!

Example Application:

This application is relatively simple. It can be thought of as a non-blocking state machine, where each ‘iteration’ of the machine must complete within 20ms. A single iteration of this machine has 4 main tasks:

1. Decode a serial payload, consisting of 32 bytes. The length is fixed at 32 bytes, payload is dynamic, baud is 115200bps (See Task #2 below)
2. Read 4 incremental shaft encoder signals, which are coupled with 4 DC Motors, 1 encoder for each motor (See Task #1 Below)
3. Determine the position of 4 limit switches. ISR driven, trigger on rising edge for each switch.
4. Based on the 3 categories of inputs above, the MCU will output 4 separate PWM signals @ 50Hz (20ms) to a motor controller for its next set of movements. (See Task #3 below)

From an IO perspective, I know that the MCU is on the hook for reading 8 digital signals (4 quadrature encoders, 4 limit switches), and decoding a serial frame of 32 bytes over UART.

Based on that data, the MCU will output 4 independent PWM signals, with a pulse width of [1000usec -3200usec], per motor, to the motor controller.

The Question:

After all is said and done, I am trying to think through how I can map my requirements into MCU selection, solely from a speed point of view.

It’s easy for me to look through the datasheet and say, this chip meets my requirements because it has (n) UARTS, (n) ISR input pins, (n) PWM outputs etc. But my projects are so small that I always assume the processor is ‘fast enough’. Aside from my immediate peripheral needs, I never really look into the actual MCU speed, which is an issue on my end.

To resolve that, I am trying to understand what goes into selecting a particular clock speed, based on the needs of a given application. Or, another way to say it, which is probably wrong, but how to you quantify the theoretical load on the processor for that specific application?

Additional Information

Task #1: Encoder:

Each of the 4 motors have different tasks within the system, but regardless, they are the same brand/model motor, and have a maximum RPM of 230. My assumption is, if at its worst case, one of the motors is spinning at 230 RPM, that would mean, at full quadrature resolution (count rising/falling for channel A/B) the 1000PPR encoder would generate 4K interrupts per revolution. As such, the MCU would have to service those interrupts, potentially creating a bottleneck for the system. For example, if (n) number of clock cycles are required to service the ISR, and for 1 revolution of 1 motor, we expect 4K interrupts, that would be … 230(RPM) * 4K (ISR per rev) == 920,000 interrupts per minute? Yikes! And then I guess you could just extrapolate and say, again, at it’s worst case, where each of the 4 motors are spinning at 230 RPM, there’s a potential that, if the encoders are full resolution, the system would have to endure 920K interrupts per minute for each encoder. So 920K * 4 motors == 3,680,000 interrupts per minute? I am 100% sure I am doing something wrong, so please, feel free to set me straight.

Task #2: Serial Decoding

The MCU will require a dedicated HW serial port to decode a packet of 32 bytes, which repeats, with different values, every 7ms. Baud rate will be set to 115200bps.

Task #3: PWM Output

Based on the information from tasks 1 and 2, the MCU will write to 4 separate PWM outputs. The pulse for each output will be between 1000-3200usec with a frequency of 50Hz.

So I am building a camera app, and currently, when I click the button in my bottom navigation, it opens the camera preview which has a button to take the photo.

When that button is clicked, it then goes and opens the native camera, instead of taking a photo.

I believe I have pinpointed the error here:

i'm working on a dashboard project (django + charts.js) that currently looks like this:

currently, all of the charts are based on all the data in the database (approx 1.5 mil lines). however, i'd like these charts to be responsive to the dates indicated in the start date/end date HTML widget - e.g. show payment methods, taxi orders by the hour/day of week according to the start/end dates indicated.

my date_input method gets the start and end dates from the frontend, and queries my MySQL database according to the dates selected. these queries are then rendered to the context variable of date_input - however, i'd like the context variable in date_input to be available to all methods (each chart is rendered by a different method, based on the JsonResponse returned to different endpoints).

i've tried making context available as a global variable by defining it outside date_input as queryset = date_input(request) - NameError: name 'request' is not defined. i've looked into context processors, but that seems to be an option only if i didn't have a request (e.g. start/end date input from the frontend). i'm rather confused and would appreciate some help.

here's my views.py code:

I am creating an app where when there is no user-generated content, it is displaying a message, but when a user takes a photo, it displays the photo in a grid gallery view.

I am already using conditional logic in order to do this, however, when I press the camera button, the camera shows up and takes a photo, however that photo does not flow back to the home page in the desired format.

There is a screenshot below regarding the flow I am trying to achieve for your reference. Hoping someone can help rectify.

I have the full reproductive code below that can reproduce what is occurring. Based on what I have, my research and knowledge, this should be achieved already as I am pushing photos taken back to the homepage_1 through the following in the Camera page

Best explained with an example. The following code gives me the result that I want, but I want to avoid the iteration/list comprehension.

I am trying to render the error message in my HTML form when a non-url is submitted, as I need to be able to easily adjust the position and apply a CSS style.

The reason I am going through this and not just simply using type=url, as I do not like the standard chrome validation error message, and I want to throw my own beneath my form.

Currently, no error message is showing when a non-url is submitted, and there are no errors in my console. Any thoughts?

HTML

I am trying to render the error message in my HTML form when a non-url is submitted, as I need to be able to easily adjust the position and apply a CSS style.

The reason I am going through this and not just simply using type=url, as I do not like the standard chrome validation error message, and I want to throw my own beneath my form.

Currently, no error message is showing when a non-url is submitted, and there are no errors in my console. Any thoughts?