table of Contents
This article mainly looks at Type-C from the perspective of an electronic engineer, not from the perspective of consumer electronics. Before talking about the Type-C interface, let's talk about the development of USB.
01, USB overview
Since the official release of USB1.0 in January 1996 (USB3.2 released in September 2017), USB has gone through 21 years. In these 21 years, the USB Standardization Organization (USB ImplementersForum, USB-IF) has produced a variety of interface forms: TypeA, TypeA SuperSpeed, TypeB, TypeB SuperSpeed, Mini-A, Mini-B, Micro-A, Micro-B, Micro-B SuperSpeed, TypeC, etc.
In addition, the USB interface is mainly composed of three parts: socket (Receptacle), plug (Plug) and cable (Cable), and superimposed on these weird specifications, disaster will happen:
Product A likes to use TypeA sockets, and Product B prefers TypeB. The cables connecting them are tragedy and can only become A-to-B. By analogy, A-to-A, B-to-B, A-to-MicroA, etc., so our drawers are full of USB cables of various unknown uses...
Physical map
02, Type-C overview
The USB-C (also known as USBType C) specification has its own independent and self-evolving specification file-USBType-CSpecification (released in August 2014, version 1.0, and version 1.3 released in July 2017). The predecessors do not have such treatment, they are all attached to the specific USB specification (USB1.0, USB1.1, USB2.0, etc.).
The previous specifications of Type C (TypeA, TypeB, etc.) focused on the "hard" characteristics of the USB interface, such as the number of signals, the form of the interface, electrical characteristics, and so on. On the basis of defining the "hard" characteristics of the USB interface, TypeC adds some "soft" content. The USB interface (only TypeC) gets rid of the affiliation with USB and becomes a new specification that can be on par with the USB specification. .
USB Type C is used as CC (CC1 and CC2) pins, using different voltages to transmit some simple information.
Later, a specification called USBPD (PowerDelivery) appeared, which implemented a simple, half-duplex communication protocol on these two pins to complete the USBpower supply negotiation. This can support extended functions. Through extended functions, the USBTypeC interface has a wireless imagination, and can be transformed into a physical interface of any other protocol, such as accessory interface, audio interface, video interface, debug interface, etc., dominating the world. The trend.
Cables or adapters defined for compatibility with old equipment
a) A cable with a full-featured Type-C plug on one end and a USB3.1 Type-A plug on the other end.
b) A cable with a USB2.0 Type-C plug on one end and a USB2.0 Type-A plug on the other end.
c) A cable with a full-featured Type-C plug on one end and a USB3.1 Type-B plug on the other end.
d) A cable with a USB2.0 Type-C plug on one end and a USB2.0 Type-B plug on the other end.
e) A cable with a USB2.0 Type-C plug on one end and a USB2.0 Mini-B plug on the other end.
f) A cable with a full-featured Type-C plug on one end and a USB3.1 Micro-B plug on the other end.
g) A cable with a USB2.0 Type-C plug on one end and a USB2.0 Micro-B plug on the other end.
h) An adapter with a full-featured Type-C plug on one end and a USB3.1 Type-A socket on the other end.
i) An adapter with a USB2.0 Type-C plug on one end and a USB2.0 Micro-B socket on the other end.
The most typical, the most common in life is the Android phone data cable.
03, Type-C pin
Female pin definition
Male pin definition
The above signals can be divided into 5 categories according to their functions:
1. Power-related signals , including
a) VBUS, the buspower of the USB cable (consistent with VBUS in our usual sense).
b) VCONN (the signal is only available on the plug), which is used to supply power to the plug (it can be inferred that there may be circuits in some plugs).
c) GND, grounding.
2. USB2.0 data cable
D+/D-. They have only one pair at the plug end, which is consistent with the old USB2.0 specification. But in order to support the pros and cons, insert at will. Two groups are defined on the socket end, so that the socket end can be appropriately mapped according to the actual situation.
3. USB3.1 data cable
TX+/- and RX+/- are used for high-speed data transmission. There are two sets of plug and socket ends, which are used to support the positive and negative plugging at will.
4. Signals for Configuration
For the plug, there is only one CC, and for the socket, there are two CC1 and CC2.
5. Signals required for extended functions
The specific usage scenarios are determined by the corresponding extended functions.
Note: Among the 24 pin signals of USBType-C, the Power type (GND/VBUS) and the data type (D+/D-/TX/RX) are completely symmetrical (for Power, no matter how it is plugged in, it is the same; For the data line, simply route it and it will work). The rest, including CC, SBU, and VCONN, are used for direction and line type detection.
04, Type-C female package
The main mainstream Type-C female sockets are 6P, 16P and 24P.
4.1、Type-C 6P
The usb type c 6p female socket is actually a special interface for high-current, high-wattage charging. Its 6Pin pin signals are defined as: GND VBUS CC2 CC1 VBUS GND. Because it does not have related definition pins for signal transmission, Strictly speaking, it does not belong to the usb3.1 series connector nor the usb2.0 connector. It is more appropriately defined as: 6P charging interface female socket with usbtype c structure specifications, which should essentially be a charger The interface, its function is just like the DC power socket we see on some products and equipment.
But as an interface with only charging properties, the usbtype c female 6P has many advantages.
One: The structure supports double-sided plugging and unplugging blind operations, bidding farewell to the drawbacks of the previous need to distinguish directions.
Second: Compared with the 24P/16P/14P in the usbtype c female connector, the manufacturing cost is greatly reduced.
Third: the usbtype c female base 6P supports over 5A high current charging, and can also be compatible with the current common fast charging protocol schemes.
From this perspective, the usbtype c female 6P model will be a popular choice when assembling interfaces for small household appliances, portable testing instruments, and functional electronic products.
Pin definition diagram
PCB package drawing
4.2、Type-C 16P
Can realize high-definition transmission interface
Pin definition, you can see that there are A6 and A7 interfaces, that is, it can be used as a USB to serial interface.
PCB package drawing
4.3、Type-C 24P
The full-featured Type-c interface can realize all the functions of Type-c. I haven't used it, and I don't know it well, so I won't go into details here.
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