Fri Sep 14, 2018 11:06 am
Hello
I have a suggestion to make about a possible hat extension board for the new M4.
I would be great if you could design a board the same size as the M4, with 2 M.2 for 80mm SSD.
If you want to make your M4 as a perfect solution, there is 2 even alternatives to that expansion board possible.
What do you think about?
I have a suggestion to make about a possible hat extension board for the new M4.
I would be great if you could design a board the same size as the M4, with 2 M.2 for 80mm SSD.
If you want to make your M4 as a perfect solution, there is 2 even alternatives to that expansion board possible.
- 2x SATA M.2
A PCIe to 2xSATA ports controller could provide the need buses for 2 M.2 sockets.
The 2 unused USB ports are accessible over 2 pin headers. Complementary extension board could be stacked and plug on those pins (USB, power pins, power key).
The SATA controller should be placed on the bottom side of the PCB because of heat dissipation, the SSD heat up a lot on the top side.
(I would have preferred 2 PCIe SSDs,but the RK3399 doesn't support PCIe port bifurcation and each lane is limited to 250MB/s, although they are PCIe v2)
- Variants
You can choose a 4 ports SATA controller.
There are 2 variants possible.
- A. 2x M.2 on the top side + 1x M.2 on the bottom side + 1 SATA connector on the bottom side for an external SSD/HDD.
This variant must be higher, if not, the M.2 #3 won't fit because of the USB/Ethernet port of the M4.
There may not be enough space for 2 M.2 sockets on the bottom side because of the USB-C connector and M4 24 pin header
- A. 2x M.2 on the top side + 2x SATA connectors on the bottom side for an external SSD/HDD.
In all variants, you have:
- - 1 USB-C port used for power delivery (The M4 can't deliver that much power to 2 SSDs). Note that this port is on the bottom side of the PCB because it won't fit on the top side because of the SSD card.
- - 1 pin header for power delivery, in the case where you don't want to make use of the USB-C port
- - A power LED, which indicates if the board is powered or if the fuse has burned
- - Power key pins (the ones on the M4 board's header
- - Power button to power up the M4 board
- - 2 onboard SSD activity LEDs (signal coming from the M.2 slot)
- - 2 SSD activity pins in case if you want to add SSD activity LEDs on the enclosure
Additional comments:
- - It's a disappointing that there is no internal USB 3 available, it would have required 6 additional pins on the header, grounds included. If it's a matter of available space on the PSB, the HDMI connector could be replaced by a smaller mini or micro HDMI.
Actually very few people need 4 USB 3 external connectors. A mouse or key board won't never need an USB 3 connection. I think you should have placed 3 external USB 3 connector + 1 external USB 2 connector. The fourth port should have been used as internal connector.
What do you think about?
