Looking for USB3 to SD Controller Chip

[Huntsman]

Hi all, I have a rpi4 project which requires plugging in full sized SD Card and dumping the data (30GB-ish worth) into the SSD (USB boot drive) and crunch through the data before sending out the result to a remote server. I have gotten the prototype working with a SanDisk USB3 SDCard reader and now I want to integrate everything into a single portable unit instead of needing to plug in a dongle. I'm thinking to put 18650 charger/BMS, USB to SATA controller and USB to SD controller into one "hat" and 3D print an enclosure to house it.

The problem I am now facing is I couldn't find a USB to SD controller chip that does USB3 speed that's easy to buy.

 

I've only found :
https://www.digikey.com/es/products/detail/cypress-semiconductor-corp/CYUSB3025-BZXI/4573039?s=N4IgjCBcoLQBxVAYygMwIYBsDOBTANCAPZQDaIALAEwIC6AvvYVWSAMICaAqgMoBCAZgAMVAKww%2BALQAaASRAMgA
http://www.prolific.com.tw/US/ShowProduct.aspx?p_id=326&pcid=153
but it's either too expensive or not sold in any of the usual online component retailer.

 

Wanted to ask the community if there's any recommendations? Thanks in advance!

[Huntsman]

32 minutes ago, James Evens said:

1. Check the TI store. For example I could order the µC directly from microchip which where out of stock at the distributor.

 

If you want cheap go to china for example GL3220.

 

Btw. In your case I would use the compute module as it provides PCIE.

Thanks! This looks promising, think they're available from chinese sites like Taobao.

 

I did thought of using the CM4 but for a first version, would stick to a normal RPI4B for now.

[mariushm]

What's stopping you from opening that sandisk card reader and mounting the circuit board somehow in your box?

I mean you can get such sd cards for less than $10 , here's an example : https://www.amazon.com/Sabrent-Micro-Card-Reader-CR-T2MS/dp/B07GZYGVT8/

You could literally use double sided adhesive tape to tape it inside the box (or tie it down with some metal clips and screws... and make a cutout for the SD card

Or you could open it, take out the circuit board, and solder wires to the sd card pins and have ribbon/ffc cable to the actual sd card.

[Huntsman]

2 hours ago, mariushm said:

What's stopping you from opening that sandisk card reader and mounting the circuit board somehow in your box?

I mean you can get such sd cards for less than $10 , here's an example : https://www.amazon.com/Sabrent-Micro-Card-Reader-CR-T2MS/dp/B07GZYGVT8/

You could literally use double sided adhesive tape to tape it inside the box (or tie it down with some metal clips and screws... and make a cutout for the SD card

Or you could open it, take out the circuit board, and solder wires to the sd card pins and have ribbon/ffc cable to the actual sd card.

OCD wants everything cleanly on one "hat". And wanting to try something new.

 

It's a good suggestion, just that I'm looking for a one board solution.

[Huntsman]

ok I give in.. it's waay too complicated and beyond my capabilities to create my own high performance sd card reader.

 

Issues I ran into:

1. These high performance sd card reader chips are not sold (even exposed) to retail or hobbyist. I can only buy from China sites which is not that bad.

2. Even if you can find the chips, documentations are next to none. Leaked datasheets don't have enough info, which I suspect the end product companies have to work with the chip manufacturer directly AFTER purchase order has been signed.

3. Also they require special firmware to be loaded in, which again there's no info on registers, tools etc.

 

Got an idea to not use USB to SD Card readers. Instead, since the RPI4's micro-SD card slot is unused, maybe wire it to a full size SD card slot and use that instead. Will have to look into if the onboard micro-SD card slot is still usable after booting from USB.

 

Thanks everyone for the input so far!