M.2 SATA to hard drive adapter board based on JMS578

Physical Display
 
 
 
 
I. Main Controller Selection
 
1. Reasons
 This project chooses JMS578 as the core for development because we have a broken hard drive enclosure, so we can disassemble the existing chip for development, including firmware. (It is also sold on Taobao for about three or four yuan each)
 
2. Main Features
  USB 3.1 Gen 1 to SATA 6Gb/s USB series bridge controllers
 conform to UASP specifications
 , support UASP protocol and TRIM command,
  support ATA/ATAPI PACKET command set
 
3. Chip Introduction
(1) Block Diagram
(2) Pin Definitions
 
II. External Interface Selection
 
1. USB Series
This project uses MicroUSB 3.0 interface for transmission, which meets the theoretical transmission speed of USB3.1 Gen1 5Gbps.
Firstly, there are many MicroUSB 3.0 data cables; secondly, this interface only has 10 pins, making soldering easier. Thirdly, in terms of hardware design, it does not require a conversion chip like the TYPE-C interface, reducing costs.
 
The following figure shows the pin definition of MicroUSB 3.0.
 
2. M.2 interface
uses M.2 B-KEY female connector as SSD connector.
 
The following figure shows the pin definition of M.2 B-KEY interface.
Source: CSDN-ltqshs
 
III. PCB part
 
1. PCB design considerations
 (1) USB 3.0 part uses differential lines with an impedance of 90Ω.
 (2) M.2 SATA part uses differential lines with an impedance of 100Ω.
 (3) Use 4-layer board design.
 (4) High-speed signal lines, crystal oscillators and inductors are not copper-plated.
 (5) The AC coupling capacitor of USB 3.0 TX part is 100nF, packaged as 0402.
 (6) The SATA part uses 10nF capacitor, placed close to the connector, packaged as 0402.
 
2. Impedance matching
Use JLCIC impedance calculation tool to calculate mechanical impedance.
4-layer PCB; 1.2mm thickness; 5mil trace spacing; JLC04121H-7628 lamination;
 
USB 3.0 section 90Ω,
 
SATA section 100Ω.
 
The actual test
used a SanDisk SD9SN8W-256GB SATA SSD covered with a heatsink.
The host computer read the data normally
during the AS SSD 1GB test.