Hard disk MSATA, SATA and M2 interface definitions

I. SATA Interface

SATA (Serial Advanced Technology Attachment) interface is a traditional hard drive interface type. It uses differential serial transmission mode, and the data transmission path is "hard drive - memory - CPU". The maximum transmission speed of the SATA interface is 6Gb/s, which is equivalent to 600MB/s. The SATA interface is not only used for hard drives, but also widely applied in optical drives, SSD solid-state drives and other devices.

Data Interface: The SATA data interface uses differential signal transmission, which has the advantages of strong anti-interference ability and long transmission distance. The interface contains multiple signal lines inside for transmitting data, clock signals, etc.
Power Interface: The SATA power interface is usually designed with 15 pins, providing two voltage outputs of +5V and +12V to meet the power supply requirements of different hard drives. Among them, +5V voltage is used for circuit power supply, while +12V voltage is mainly used for the spindle motor power supply of mechanical hard drives.

II. mSATA Interface

mSATA (mini-SATA) interface is a mini version of the SATA interface, mainly used in small-sized and lightweight electronic devices such as laptops and tablets. The mSATA interface has the same size as the Mini PCIe interface, but the arrangement of the pins is different, so they cannot be used interchangeably.

Interface size and pin arrangement: The size of the mSATA interface is 50mm × 30mm, and the pins are arranged alternately on both the front and back of the interface. This design enables the mSATA interface to fit more closely to the motherboard, saving space.
Pin definition: The pin definition of the mSATA interface is similar to that of the SATA interface, including data transmission pins, power pins, etc. However, it should be noted that the mSATA interface does not have a separate clock signal pin; instead, it uses differential signal transmission, with the clock signal embedded in the data signal.
Compatibility: The mSATA interface can be compatible with the SATA channel, so hard drives using the SATA protocol can be used. However, it should be noted that due to the smaller size of the mSATA interface, its heat dissipation performance may not be as good as that of the standard SATA interface.

III. M.2 Interface

The M.2 interface is a new type of solid-state drive interface. It features a smaller size and higher transmission speed, and is widely used in modern laptops, desktop computer motherboards and other electronic devices. The M.2 interface is divided into two modes: B mode and M mode. The B mode is compatible with SATA and PCIE channels, while the M mode can only use the PCIE channel.

Interface size and specifications: The M.2 interface has various size specifications, such as 2242, 2260, 2280, etc., representing the width and length of the interface. These specifications enable the M.2 interface to fit different-sized solid-state drives.
Gold finger arrangement: The gold fingers of the M.2 interface are also arranged alternately on both sides, similar to the mSATA interface. However, the M.2 interface has more gold fingers, providing more data transmission channels and power pins.
Transmission speed and channels: The transmission speed of the M.2 interface depends on the type of channel it uses. The B mode is compatible with SATA channels and has a maximum transmission speed of 6Gb/s; while the M mode uses the PCIE channel (full-duplex mode), with a maximum transmission speed of up to 10Gb/s or higher (such as PCIE 4.0 version). Additionally, the M.2 interface supports the NVMe protocol, further improving data transmission efficiency and response speed.
Compatibility: The M.2 interface has high compatibility and can support different types of solid-state drives, including SATA protocol and PCIE protocol drives. However, it is important to note that different motherboards may support different channel types and protocol versions. Therefore, when purchasing a solid-state drive, it is necessary to carefully check the specifications of the motherboard.