The watchdog timer WDT is a bit counter. When the timer counts down to zero, it can either trigger an interrupt or reset the microcontroller. Why is this useful? Imagine your microcontroller is on a system where a person cannot easily access. This could be on an industrial machine, out in space, on a car, or a data logger in some remote location. For some reason, your code gets stuck in a loop, or freezes while it waits for some resource, or stops responding for any reason. Another case is where waiting too long to be reset could be a problem, like in a motor control application. This is where the WDT comes in handy. Once you start the timer, it will constantly count down.

Enable I2C Interface on the Raspberry Pi

The project will be a simple one, the STM8S will take a stream of bytes and perform simple addition. When requested, the STM8S will return the total as a bit integer. Each new write request will clear the current total and start the whole process again. This post is a fairly long as it contains a lot of code so it might be a good time to grab a beer and settle down.

I2C and SPI are reserved for expanding 9. All the MOSFET can be controlled by PWM Use the interface of servo motor to adjust the level of printing platform automatically. Adding a SD module for SD ramps module. LED can indicate the status of the heater (the open and close of MOS).

The way around that problem is to use an I2C display. I2C only uses two lines, A4 and A5. It has been a standard for many years, and is a popular way to talk to an LCD. The Arduino has a software library which turns one of the internal serial devices into an I2C port. Both the LCD and backpack are readily available and very inexpensive. Start by making a four-wire cable following this fairly common color code. The reason for the color code is to prevent hooking up the cable wrong and destroying the LCD.

It will become second nature to hook up the LCD correctly just by memorizing which color goes where. Before we can go any further we have to install the I2C library code. You can get a really good I2C library and install it, but you have to remove the existing LCD libraries. Arduino comes with the Adafruit LCD library installed. It can be removed by deleting or moving the “LiquidCrystal” library folder.

On Windows, the LiquidCrystal folder is in the C: Click that and tell it where the zip file you downloaded can be found.

Taking the Leap Off Board: An Introduction to I2C Over Long Wires

If we look at our cable topology, a signal wire and a ground wire form exactly that—an unwanted capacitor! The longer our cable grows, the bigger this capacitor grows. However, as that wire distance grows in size, that parasitic cap takes our nice clean signal and starts attenuating it. Why is this happening? A wild lowpass filter has appeared! The received signal emerges not in that pristine, staccato square wave that we all know and love, but a diluted representation of the original, as if staggering back home from a rough night at the pub.

Oct 31,  · I have read piles of doc’s and different threads but I’m unable to be sure of which i2c bus to use and what pins to use when hooking up my i2c device.

On early prototype boards, it is recommended to include small shunt resistors in the voltage rail paths of each of the following rails of AM x: This will help you measure the power consumption of each rail and potential pinpoint high power consumption during development. You may also want to add these shunt resistors for other devices power supplies to be able to measure power for key devices. For production, these shunt resistors should be removed from the design i.

For your main clock e. There is a power benefit to using a crystal because there is hardware inside the chip that can shutoff the crystal entirely during DeepSleep0 DS0. When using a square wave clock there is unfortunately no mechanism for automatically turning the clock off and on, which results in additional current consumption.

This will enable the regulator to be switched off during DS0. The 32KHz reference can come from the high frequency clock. It is preferable to always have bias and dampening resistors that can help tune the crystal later. These guidelines are very important to ensure a proper DDR design.


I2C bus technology uses only 2 pins of the MCU so we have heaps available for other sensors. Closer Look Lets have a closer at these two displays. So, how can we achieve this? The trick is to have a configurable address on your display. This unit has a configurable address between 0x78 and 0x7A. Just by unsoldering the 0Ohm resistor from one side and hoking it up to the other side or just by putting a global solder we can change the address.

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The color version pi camera has nm IR cut filter on top of the sensor, so it can only sensitive to visible light like human eyes. So people will think NoIR pi camera is better than the standard color pi camera, because it is sensitive to all spectrum rather than visible light. Yes, it is good, but it depends. The problem of this effect is that the color reproduction is drastically affected. The image below shows the result. The plants in this view reflect more infrared than green light so they appear pink in daylight.

To make the image more akin to what humans can see, most cameras are fitted with an infrared-cut filter which only allows visible light to pass through, reflecting unwanted infrared. This is where standard color version pi camera used for. Motorized Switchable infrared-cut filters There are some instances where capturing infrared light is an advantage. In low-light conditions, cameras capture as much light as possible to produce brighter images, regardless of color.

The optimum solution is to use a switchable infrared-cut filter. In daylight, the filter covers the sensor to provide color footage, while at night the filter opens for a brighter image. Solution Sometimes you need the camera to work on both daylight and dark night time conditions, like the IP-based security camera.


All my projects are posted to my facebook page at http: The below images was taken from his proposal to the festival. Bolt idea and concept After understanding the requirements from the artists, we started exploring various way to drive the LED strips, from simple relays with delays to wireless options. The idea was to use the delay to turn on and off the LED strips. The idea was to have eight passive I2C slaves just receiving commands from the I2C master and all my coding would be centralized in the I2C master.

This makes controlling the code version easily and any changes does not need to re-flash all the 8 I2C slaves.

Now, what if you want to hook up more than 2 displays? Arduino has limited number of pins and hence you cannot have more than a certain amount of shields attached to it. Moreover, it has only one pair of I2C .

Other sites, like adafruit, got the same displays if you prefer to shop there. Add Tip Step 1: Connecting Your Display The display is connected by utilizing the i2c pins on your arduino. I first attempted to power my display from my arduinos 5v. This worked, but only halfway — the display fired up, and started cycling the demos in the sketch we will see later on, and then froze after a few seconds.

I then powered my display from my external 5v supply with common ground to the arduino , which did the trick — the display is now working properly. The connections from the display: The USB powers the arduino. Add Tip Step 2: I2c Scanner To start out, we need to find out the i2c address of the display. To accomplish this, I use a quick i2c scanner uploaded to the arduino. The scanner code can be found on http: Copy and paste the code into your arduino IDE, build and upload, and fire up your serial monitor.

If your display are connected, powered and working, you will get an address back from the scanner in serial monitor.

Drive a TFT LCD with Capacitive Touchscreen

Luckily, there is a Dallas Temperature library for the arduino which makes using this sensor very easy. The most recent version of this library can be found at Download a copy of the library. Now, before we get to the programming part, lets wire up our temperature sensor. The DS18B20 can be powered by between 3. However, the DS18B20 can also extract its power from the data line which means we only effectively need two wires to connect it up.

STM8S I2C Slave Device Having succeeded at getting a basic I2C master working on the STM8S it is not time to start to look at I2C slave devices on the STM8S. The project will be a simple one, the STM8S will take a stream of bytes and perform simple addition.

This month I plucked my favorite solution from the bunch and gave it a spin. From all of the choices we covered, I picked differential signals. Suppose we have two devices that want to communicate over a single wire. To get the conversation started, we run a single-ended signal over a long cable from one device to another. Just imagine a lengthy hookup wire between breadboards. Now, suppose we add some electromagnetic interference EMI by introducing a nearby motor and turning it on.

Our encoders will read random numbers, steppers will take bonus steps, buttons will read: In this setup, the receiver reads the difference between the top and bottom channels.

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