Customized Mini USB Interface and Cable

What is a USB interface? The function and fabrication of precision USB interfaces.
Universal Serial Bus (English: Universal Serial Bus, abbreviation: USB) is a serial bus standard and a technical specification for input and output interfaces. It is widely used in information and communication products such as personal computers and mobile devices, and has been extended to other related fields such as photographic equipment, digital TV (set-top boxes), and game consoles. The latest generation is USB4, with a transmission speed of 40Gbit/s, a three-stage voltage of 5V/12V/20V, and a maximum power supply of 100W. The new Type C interface allows positive and negative blind insertion.

How the USB interface works
USB is an external bus standard that regulates the connection and communication between computers and external devices. The USB interface has a hot-swap function. The USB interface can connect a variety of peripherals, such as mouse and keyboard. USB was jointly launched by Intel and other companies in 1996 at the end of 1994. It has successfully replaced serial ports and parallel ports, and has become a must-have interface for computers and a large number of smart devices today. The USB version has gone through years of development and has now developed into the USB4 version. For most engineers, the main obstacles to developing USB2.0 interface products are:
To face the complex USB2.0 protocol, write the driver of the USB device by yourself, and be familiar with the programming of the single-chip microcomputer. This not only requires considerable experience in VC programming, but also the ability to write hardware (firmware) programs for USB interfaces. So most people give up developing USB products by themselves.

The development history of USB interface
USB 1.0
USB 1.0 appeared in 1996, with a speed of only 1.5Mb/s (bit per second); it was upgraded to USB 1.1 in 1998, and the speed was greatly increased to 12Mb/s. This standard interface can still be seen on some old devices. USB1.1 is a relatively common USB specification, and its high-speed transmission rate is 12Mbps. The transmission rate of the low-speed mode is 1.5Mbps (b means Bit), b/s generally indicates the bit transmission speed, and bps indicates the bit transmission rate, which are equal in value. B/s and b/s, BPS (bytes per second) and bps (bits per second) should not be confused. 1MB/s (megabyte/second) = 8Mbps (megabit/second), 12Mbps = 1.5MB/s, most MP3s are of this type of interface.

USB 2.0
The USB2.0 specification evolved from the USB1.1 specification. Its transmission rate has reached 480Mbps, converted to MB is 60MB/s, enough to meet the rate requirements of most peripherals. The “Enhanced Host Controller Interface” (EHCI) in USB 2.0 defines an architecture compatible with USB 1.1. It can drive USB 1.1 devices with USB 2.0 drivers. In other words, all devices that support USB 1.1 can be used directly on the USB 2.0 interface without worrying about compatibility issues. And accessories like USB cables, plugs, etc. can also be used directly.
The change brought about by the use of USB for printer applications is a substantial increase in speed. The USB interface provides a connection speed of 12Mbps, which is more than 10 times faster than the parallel port. At this speed, print file transfer times are greatly reduced. The USB 2.0 standard further increases the interface speed to 480Mbps, which is 20 times the speed of ordinary USB, and greatly reduces the transmission time of printing files.

USB 3.0
The USB 3.0 Promoter Group is composed of industry giants such as Intel, Microsoft, Hewlett-Packard, Texas Instruments, NEC, and ST-NXP. The next-generation USB 3.0 standard that the organization is responsible for formulating has been officially completed and released publicly. The theoretical speed of USB 3.0 is 5.0Gb/s, but in fact it can only reach 50% of the theoretical value, which is close to 10 times that of USB 2.0. The physical layer of USB3.0 adopts 8b/10b encoding method. The theoretical speed calculated in this way is only 4Gb/s, and the actual speed has to deduct the protocol overhead, which is less on the basis of 4Gb/s. Can be widely used in PC peripherals and consumer electronics.
USB 3.0 will be called “USB SuperSpeed” in actual device applications, following the previous USB 1.1 FullSpeed and USB 2.0 HighSpeed. Commercial controllers supporting the new specification are expected to be available in the second half of 2009, and consumer products are already on the market.
USB 3.1
USB 3.1 Gen2 is the latest USB specification, which was initiated by companies such as Intel. The data transmission speed can be increased to a speed of 10Gbps. Compared with USB 3.0 (ie USB 3.1 Gen1) technology, the new USB technology uses a more efficient data encoding system and provides more than double the effective data transfer rate. It is fully backward compatible with existing USB connectors and cables.
USB 3.1 Gen2 compatible: existing USB 3.0 (ie USB 3.1 Gen1) software stack and device protocol, 5Gbps hubs and devices, and USB 2.0 products.
USB-IF’s latest USB naming convention, the original USB 3.0 and USB 3.1 will no longer be named, and all USB standards will be called USB 3.2. Considering compatibility, USB 3.0 to USB 3.2 are called USB 3.2 Gen 1, USB 3.2 Gen 2, and USB 3.2 Gen 2×2 respectively.

USB 4.0
The USB4.0 specification was published by the USB Implementers Forum on August 29, 2019. USB4 is based on the Thunderbolt 3 protocol. It supports 40 Gbit/s throughput, is Thunderbolt 3 compliant, and is backward compatible with USB 3.2 and USB 2.0.

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4 channel USB interface card module

The main advantages of the USB interface
USB devices mainly have the following advantages:
1. Hot swappable. That is, when users use external devices, they do not need to shut down and restart, but directly plug in the USB to use when the computer is working.
2. Easy to carry. Most USB devices are known for being “small, light and thin”. It is very convenient for users to carry a large amount of data with them. Of course, the USB hard drive is the first choice.
3. Unified standards. The most common ones are hard disk with IDE interface, mouse and keyboard with serial port, and printer and scanner with parallel port. But with USB, all these application peripherals can be connected to personal computers with the same standard. At this time, there are USB hard drives, USB mice, USB printers and so on.
4. Multiple devices can be connected. USB often has multiple interfaces on personal computers, and several devices can be connected at the same time. If you connect a USB HUB with four ports, you can connect another four USB devices. By analogy, you can connect as much as possible, and connect all your home devices to a personal computer at the same time without any problems (Note: up to 127 devices can be connected).

USB interface arrangement
USB is a commonly used pc interface, it only has 4 wires, two power and two signals, so the signal is transmitted serially. The usb interface is also called a serial port, and the speed of usb2.0 can reach 480Mbps. It can meet various industrial and civil needs.
The output voltage and current of the USB interface are: +5V, 500mA. In fact, there is an error, the maximum cannot exceed +/-0.2V, that is, 4.8–5.2V. The 4 wires of the usb interface are generally allocated as follows. It should be noted that the positive and negative poles must not be reversed, otherwise the south bridge chip of the usb device or computer will be burned:
Black line: gnd; red line: vcc; green line: data+; white line: data-.

USB interface wiring color
The general arrangement is: red white green black from left to right.
definition:
Red – USB power supply: marked with -VCC, Power, 5V, 5VSB.
White – USB data cable: (negative) – DATA-, USBD-, PD-, USBDT-.
Green – USB data cable: (positive) – DATA+, USBD+, PD+, USBDT+.
Black-ground wire: GND, Ground.

Type of USB interface
With the popularization of various digital devices, especially the popularization of MP3 and digital cameras, there are more and more USB devices around us. However, although these devices all use USB interfaces, the data cables of these devices are not exactly the same. These data cables are all the same at the end connected to the PC, but when connected to the device end, various interfaces are usually adopted for volume considerations. The following briefly introduces various applications of the Mini type sub interface.

B-5Pin
This interface can be said to be the most common interface. This kind of interface is gaining the attention of more and more manufacturers due to its excellent anti-mis-insertion performance and relatively small size. Now this kind of interface is widely used in card readers, MP3 players, digital cameras and mobile hard disks.

B-4Pin
This interface is common in digital products of the following brands: C series and E series of Olympus, most digital cameras of Kodak, MP3 products of Samsung (such as Yepp), DSC series of SONY, IPAQ series products of Compaq.
There is another form of Mini B 4Pin, which is Mini B 4Pin Flat. As the name suggests, this interface is flatter than the Mini B 4Pin, and it is widely used in devices.

B-8Pin
Mini B type 8Pin Round
Compared with the previous common type, this kind of interface is to change the original D-type connector into a circular connector, and a protrusion is designed on the side to prevent mis-insertion.
This kind of connector can be found in some Nikon digital cameras, and the CoolPix series is more common. Although Nikon has always insisted on using this interface, some newer models, such as D100 and CP2000, also use the most popular Mini B-type 5Pin interface.

B-8Pin-2×4
This interface is also a relatively common interface, such as iRiver’s famous MP3 series. Among them, the 180TC, known as the “Iron Triangle”, and many other products in this series use this interface. The application scope of this kind of interface is quite wide, but since iRiver completely replaced the Mini B 5Pin interface from the 3XX series, this specification is obviously not as eye-catching as the Mini B 5Pin.

Micro USB
It complies with the USB2.0 specification and supports a data transfer rate of 12Mbit/s. The module connects the control pins according to the Microport interface to facilitate the connection with the host controller supporting the Microport interface. On October 26, 2009, the ITU-T Study Group 5 (SG5) plenary meeting held in Geneva, Switzerland, completed the discussion on the framework standard of “Power Adapter and Charger Solution for Universal Mobile Terminals and Other ICT Equipment” and passed it. And apply to enter the approval process. This actually means that the world will unify the mobile phone charger standard.

Type-C is a brand-new USB interface form, which was born with the latest USB 3.1 standard. Released by the USB-IF organization in August 2014, it is a brand-new interface developed by the USB standardization organization to solve the long-term inconsistencies in the physical interface specifications of the USB interface and the fact that power can only be transmitted in one direction. It integrates charging, display, data transmission and other functions in one. The biggest feature of the Type-C interface is that it supports two directions of insertion, which officially solves the worldwide problem of “USB can never be inserted correctly”, and can be inserted at will.

The TYPE-C hardware interface has obvious characteristics, mainly as follows:
(1) Support positive and negative symmetrical plugging, to solve the problem that the reverse plug cannot be inserted in practical applications;
(2) The interface is slim, which can support thinner and lighter devices, and can make the design of portable devices thinner and smaller;
(3) Support higher power transmission, up to 100 watts, and support more high-power load devices.
(4) Support single-port and dual-port TYPE-C, flexible application.
(5) Support two-way power transmission, both for power transmission and power reception.

TV application with USB interface
different functions
Although many TVs are equipped with USB ports, the functions that can be realized after connecting a storage device through the USB port are not the same. Some TVs only support playing pictures from USB storage devices, while others can play music files and videos in certain formats.
usb cable
When it comes to USB playback capabilities, the current domestic TVs are still relatively good in USB playback capabilities. H.264 encoding and HD video in RM/RMVB format can generally be played smoothly. Although there is still a gap in the effect compared with high-end high-definition players, it is enough for ordinary users to use.
TV USB port
Figure 2 below shows the usb interface on the side of the TV, which can be directly connected to a U disk or a mobile hard disk.