Wiretrustee has designed a four-port SATA carrier board for the Raspberry Pi Compute Module 4, offering 220MB/s throughput for compact low-power NAS applications — and is considering a crowdfunding campaign to have the design mass produced.
"After watching a couple of videos from Jeff Geerling I thought I might try it out and build my own SATA carrier board for the CM4," an unnamed Wiretrustee representative explains. "I'm not chasing high IO therefore a limitation of PCIe x1 wasn't a real problem to me. I still think you could have a decent speed with only one lane especially for my case where I anyway will connect and download/upload files from/to the home network via the internet (mobile mostly)."
"So I made a decision and started building my own carrier board for CM4 since the alternative was a huge IO board with the PCIe card or some custom board but again with a PCIe card. After a couple of days, I realized that I'm too optimistic about it and I have not enough knowledge of the complex PCB design. So instead of studying and improving my skills (sarcasm) and a 2-week break, I found a professional designer, took a part of my savings, and started the project."
The board accepts any model of Raspberry Pi Compute Module 4 and adds four SATA 2.0 ports, a microSD slot, a gigabit Ethernet port, HDMI 2.0, two USB 2.0 ports, a four-pin fan header, real-time clock with battery backup, a front-panel control board, and USB Type-C power connectivity — all in a footprint of just 100x100mm.
"The integrated Marvell 88SE9215 controller does the PCIe <-> SATA signal conversion (that was the one that scared me when I tried to design myself)," the representative explains. "We've tested it with the Raspberry PI OS and it has a write speed of ~220MB/s on each of the SATA ports (not simultaneously of course)."
More details of the board have been published to the Wiretrustee website, with plans to bring the design to Crowd Supply for mass production pending certification. Further discussion can be found on Reddit.