design: add M.2 slot for NVME drive

EvanKrall / pipad

A PCB for putting a Raspberry Pi CM4 inside a 1st-generation iPad.

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design: add M.2 slot for NVME drive #20

Closed EvanKrall closed 2 years ago

EvanKrall commented 3 years ago

https://global.kyocera.com/prdct/electro/product/pdf/6411.pdf kyocera has a 2.25mm socket: https://www.digikey.com/en/products/detail/246411067101894B/1253-1602-1-ND/5814321?itemSeq=371692007

EvanKrall commented 3 years ago

oops I probably would want the M key socket, not the B key. (Even though the SN520 I bought is B+M keyed, most NVMe drives are only M key.)

https://www.digikey.com/en/products/detail/kyocera-international-inc-electronic-components/246411067101894M/5814311?s=N4IgTCBcDa4CwDY4EZkAYEHZ3IBwE44BbEAXQF8g

EvanKrall commented 3 years ago

https://github.com/mfolejewski/MirkoPC/blob/81a24fadfe165a523ffb9167838d34fb3440f881/REV1.1/MirkoPC_V1R2_Schematic_20210507.pdf Sheet 8 of 17 shows the schematic for the M.2 connector on the MirkoPC, which has well-tested NVMe boot capability.

EvanKrall commented 3 years ago

The MirkoPC provides its own 3.3V rail for the NVMe drive. Probably a wise choice - the SN520 claims to use up to 3W (1A), but I think other drives might be able to pull more.

EvanKrall commented 3 years ago

Jeff Geerling's experience with the SN520: https://github.com/geerlingguy/raspberry-pi-pcie-devices/issues/90

EvanKrall commented 3 years ago

The next challenge is where to find the solder-down standoffs. I think this is the appropriate standard to follow (from the m.2 specification):

EvanKrall commented 3 years ago

I think this is the right standoff/nut: https://www.mouser.com/ProductDetail/JAE-Electronics/SM3ZS067U215-NUT1-R2500?qs=%2Fha2pyFadugicYoHRiH4SZQzG8ljRBTZKp0yzKCNtLVH3u6K1jx7piAxI%2FbUaw%252Bs

EvanKrall commented 2 years ago

this is added in both the cm4 and radxa_cm3 branches