TOP 6: what are USB TTL PL2303 adapters, what are they for, prices

The small-sized USB TTL PL 2303 adapter is a kind of programmer used with a board to read information from various sensors:

• humidity;
• temperature;
• movements.

This is the reason for the widespread use of the USB TTL PL2303 adapter in radio-controlled devices. The TTL USB adapter is programmed in C++, i.e. The USB TTL adapter is a "universal bus" for data transfer used in low and medium speed computing technology.

To connect it to the USB RS232 TTL adapter you need a four-wire cable. One twisted pair is needed for differential connection during reception and transmission (RX and TX), and the remaining ones are needed to supply power to peripheral devices (GND and +5V).

Provided that the maximum current of such devices does not exceed 500mA, and for USB - 900mA), they are connected without their own power source.

Despite the fact that for TTL logic 0-5 V there are standard levels, like a USB TTL adapter is not needed.

But, due to the fact that the USB interface/protocol is quite complex, building a device based on it requires deep knowledge and microprocessors that process the data.

Another protocol can be used to help - UART (UART), which is the most common today. Among the family of many protocols, the most commonly used is RS-232, commonly referred to as the COM port. It is the oldest of all, but still relevant today.

We recommend:

• DC motor: characteristics, structure, main differences
• Flight recorder, or top video recorders
• Do-it-yourself electric motor?

It has lines:

• transmitting - TXD;
• host - RXD.

If they are used to transmit data, then there is no need for hardware control. For hardware, DTS and RTS are used.

The transmitter output is connected to the receiver input and vice versa.

RS-232 differs from standard (5-volt) logic in its electrical principle of operation. In this version, “0” lies in the range of +3 to +12 V, respectively, one is in the range from -3 to -12.

Conclusion. The purpose of UART USB TTL adapters is to “join” a complex interface

USB with a simple and “running” UART protocol, supported by microcontrollers, and working with logic levels 0-5V.

What is TTL flash metering?

TTL flash metering mode means automatic. The abbreviation TTL stands for “Through the lens”, which means “through the lenses”. This suggests that the power of the illuminating pulse is determined automatically by measuring the degree of illumination of the frame through the optical lenses. This is accomplished thanks to the preceding impulse. It passes through the lens and measures the exposure of the future photograph.

While developing, TTL metering technology changed several times. Previously, film SLR cameras had a way of analyzing the illumination of the frame using an infrared pulse. Over time, automatic flash control technology using a pre-pulse has emerged. Nowadays, there are also flash cameras that can provide distance between the subject and the shooting point.

The TTL flash mode makes the photographer’s work easier, because the light pulse power, zoom and other settings are selected independently by the technician, taking into account the set values ​​of ISO, shutter speed, aperture, etc. The main thing is not to exaggerate the capabilities of technology. If you close the aperture too much, it may not be powerful enough to illuminate the frame well. When shooting indoors, it is better to open the aperture as wide as possible, while setting the ISO to medium. Thus, with the TTL exposure metering function, you can take optimal photos.

Bypassing blockages

The blocking is quite simple - you need to set the TTL on the connected devices, which will be exactly 1 more than that of the distributing phone. For example, you distribute the Internet to a laptop, then you need to set this device’s TTL to a value 1 greater than that of the distribution device (that is, 65). As a result, the packet from the computer reaching the phone will take the value 64. The operator will see that all packets are the same and will not block anyone.

NOTE! You can, of course, not reduce the TTL on the receiving device, but reduce it on the distributing device, but for this you will need ROOT rights and the TTL Master program. Therefore, it is easiest to change the value on secondary devices - more on this below.

But there is one more catch, which for some reason is not written about anywhere. The fact is that operators also began to calculate the distribution differently. The provider has a list of servers that can only be accessed from a computer.

For example, if a Windows update starts on a connected computer, the operator will immediately understand this. Because no one in their right mind would access Microsoft update servers from their phone. The list of such servers is constantly growing. But this problem is quite easily solved. On this occasion, we have detailed instructions for all operators on our portal:

• MTS
• Beeline
• YOTA

All the steps are described there with pictures and explanations. You can also determine and check your TTL, but in fact they have the same values ​​for all types of devices that I wrote about at the very beginning.

Limited capabilities

Most often, automatic flash metering selects the optimal operating parameters for a particular frame. But it is important to remember that technology will not always be able to take into account all the details of the shooting. TTL mode determines optimal flash performance based on the degree of illumination of the middle gray areas in the frame. A good automatic lighting setting should only be expected when the light is directed directly at the object. If there are areas in the frame that reflect light, the automation will not be able to correctly calculate how the reflection will turn out. After all, it is difficult for technology to determine the correct distance to the subject and the angle of reflection of the light flux. In such cases, autotuning occurs in an incompletely defined mode.

The most convenient and reliable USB-TTL COM converter I've ever come across

One of those things, quality things that you use for many years and don’t notice. And when you need one again, having looked at the analogues, you are looking for “just exactly the same.” There is probably no need to explain to amateurs and professionals what a USB-COM converter is. But usually, according to the laws of the genre, there is still an introductory word. And while you are choosing these introductory words, sometimes you yourself learn something new. I won't back down. Serial port, aka RS-232, aka COM port, aka C2 interface, a bandit in general. The standard was adopted in 1969, when it was born - it was not possible to find it. Describes the physical level of information transfer between... I don’t know between what anymore. Probably then - between computers. In the future - and between the computer and peripheral devices. And as far as I remember, the voltage levels were wild +- 12 volts. +12 - the line is inactive, log.1, and minus 12 - active, log.0 Time passed, the COM port was replaced by USB, many predicted the death of the COM port... How naive they were. The COM port is the most alive of all living things, and I think it won’t even go anywhere until the end of this century. In many modern computers it is no longer installed, or there is only one of it, and it is not even included with the motherboard. And there is a lot of equipment that works using this protocol, so USB adapters are our everything. I have not purchased this adapter before. It was sent to me by the company CDSNET, which is quite well known in narrow circles. I’m not afraid of the word company, I’ve probably known their products for about 7 years. I didn’t send it just like that, but as an accessory to their transceivers. These digital transceivers are a very high-quality item, captured in the photo - essentially a radio extender of a COM port, allowing you to transmit information over a distance of up to a couple of kilometers (depending on the building, antenna, transmission speed). Don't look at the frequency - I can. ))

But we are still not talking about them, but about this COM adapter, which, fortunately, they also sell separately. Although not the cheapest. About the adapter. It is built on a CP2102 from Silicon Labarotories, quartz-free, and creates the necessary frequencies internally via a PLL synchronized via SOF packets. Oops, I write popularly. So, this is not FTDI, which cheated millions of users around the world by making an original decision to fight counterfeits of their converter chips by erasing the USB VID/PID in them. That is, turning iron into garbage. They were then dragged through the courts, because... clones were in the final equipment or not clones, but according to their laws... in short, I don’t know what is there according to their laws, but they got a lot of problems and disgust from professionals and amateurs. This is the most problem-free adapter in my approximately 25 years of using them. In Linux, no driver is needed. On Windows - from the website and without problems. This is all thanks to the chip. What I like about the board itself from CDSNET is that it is probably the smallest of all. It doesn't need a cord; it plugs directly into the USB connector. I consider the pin ruler, paralleled with the socket ruler, to be a huge advantage. It becomes possible to use everything that is at hand, even plug in a bare wire. Or, for example, if two receivers are needed for the TX line at once. Of course, you can solder everything, solder it, etc. But whoever works with all this stuff often and a lot will understand, I think, how convenient it is. It is not forbidden to steal a little power from the adapter for your needs, 3.3 or 5 volts. I didn’t measure exactly how much, but probably 200 milliamps will give.

The jumpers are on the right - as funny as they are, I haven’t figured out why in many years. Something is being shortened to the ground. It was not necessary. There is a jumper on the left - you can select the RX-TX level will be 3.3 or 5 volts. One LED lights up when power is supplied, and the second one seems to be on when exchanging. I probably don’t have anything special to write about - this is a good old friend who hasn’t let me down for many years and won’t let me down. I have 6 of them, but I needed more for work, I barely found these very ones, and at the same time I decided to share with Musya. PS - RTD DTS and nothing else. And personally, I never needed them. All.

Available adjustments

TTL metering mode has the ability to adjust flash settings. Using the automatic mode, you can control the strength of the preliminary impulse, making it weaker or stronger than provided by the technology. The name of this setting is flash compensation. In this case, the pulse compensation level is manually adjusted to a value on a scale from -3 to +3. If, in your opinion, the automation made an impulse that was too powerful, you can reduce its power or increase it in the opposite situation.

Also among the possible settings, you can select the exposure metering mode. When shooting complex light scenes, for example, in front of a light source, when additional lighting is needed in only one area of ​​the frame, you can set the exposure to partial or spot metering mode. Without this setting, the camera takes into account the lighting throughout the frame, calculating the exposure for all areas of light in the frame. By choosing the right settings, you can get additional exposure in one area of ​​the frame and reduce additional lighting in another.

FT232RL USB 3.3V 5.5V to TTL mini port

Its cost is 106.43 rubles. This is an inexpensive option to increase the USB capabilities of microcontrollers. For protection, a 500ma self-resetting fuse to protect against current overloads.

Characteristics

• color – red;
• power supply USB-5 or 3.3 V;
• weight – 4 grams;
• dimensions - 43x17 mm.

Its small size makes it possible to use it in developments where the size of the gadget is critical.

Pros and cons

• TTL flash metering mode has both positive and negative sides;
• A significant advantage is that automatic light metering makes it possible to take into account lens parameters. Thanks to this, exposure metering is carried out taking into account the lens aperture, external filters and viewing angle;
• This technology will also appeal to photographers who often do reportage shooting. When there is very little time for detailed configuration of all equipment;
• The automatic mode is also suitable for beginners in photography, since understanding the flash settings is quite difficult.

The disadvantages include the rather high cost of branded equipment with the TTL function.

System operating modes

Self-adjusting flash settings determine the desired power based on more than just exposure metering from the previous flash. This is also influenced by the operating mode of TTL metering, of which there are several:

1. Ordinary. In this operating mode, exposure analysis occurs using the camera's internal system. In this case, the evaluative impulse does not work. Thanks to special sensors, the system recognizes the use of various filters. If they are present, automatic power adjustment will occur;
2. Automatic metering. This mode assumes the presence of a preliminary impulse. In this case, the sensors read information about the degree of illumination of the frame. After this, the parameters of the main flash are automatically calculated. The preceding pulse is triggered when the shutter button is pressed halfway;
3. Estimated measurement. This type has greater accuracy in measuring exposure and is also distinguished by its speed. The evaluation pulse fires milliseconds before the main one. This means that if you press the shutter button halfway, no additional flash will appear. The pulse is triggered only when the shutter is fully released. The evaluation pulse is practically invisible to the human eye, but despite this, the camera manages to calculate the required power of the main flash. After which a picture is taken with the main impulse already corrected.

Usb Ttl Module Adapter PL2303HX with Flexible Cover

The USB RS232 TTL Pl 2303 adapter is assembled on a PL2303 chip, which creates a virtual COM port on a PC. Used for flashing devices with microcontrollers.

Its cost on https://ru.aliexpress.com/popular/ttl-adapter.html is 40.84 rubles.

To deliver to Ukraine you need to pay an additional 149.74 rubles.

Main Features of PL2303 USB to TTL Module Adapter Converter:

• voltage type – regular;
• power supply – 3.3/5 V;
• purpose - for computer;
• temperature range - -40 TO +85;
• Manufacturer: Diymore.