Today I purchased a USB memory card reader. I cracked it open and saw that it basically only has an AU6477CL IC, which is based on the AU6370, which is a chip which takes SD/MMC/etc pins as input and acts as a USB driver for a computer to do i/o on the card. Here is the datasheet for the AU6370.

Where can I buy one of these things? It seems like every card reader in the universe is driven by one of these ICs, but short of buying 50,000 from alibaba (maybe), I can't find them anywhere.

Alternately, does anyone know of equivalent ICs which perform similar functions? Generically, what would I be searching for?

For hobbyists, is the best option really to use an AVR/PIC to write our own code (or existing libraries) if we were to create our own memory card reader?


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  • \$\begingroup\$ Try to use the MAX14502, which is available at Mouser \$\endgroup\$ – user6786 Nov 28 '11 at 12:51
  • \$\begingroup\$ Unfortunately, the MAX14502 is now NRND and one variants are EOL. \$\endgroup\$ – Damien Mar 31 '16 at 6:33

The cheapest way of getting the part is by buying a card reader from your favorite eBay Hong Kong vendor.

I was involved in purchasing AU6350s for a project. The process involved lots of transcontinental communications, purchase orders, international wire transfers, and shipping accounts. The developer board was about $150 if I remember correctly. The Alcor people are nice, but there is just a lot of bureaucracy.

The Microchip USB stack has a card reader as one of their example projects. It works fine, but is very slow compared to the dedicated chip. About 50 times slower by my memory.

  • \$\begingroup\$ I would speculate that Microchip is using the SD card in MMC mode, to avoid having to pay the SD consortium licensing fees. \$\endgroup\$ – Adam Lawrence Apr 15 '11 at 13:30
  • \$\begingroup\$ Yes, they are using the SPI interface. But they are also only full-speed USB, where the Alcor chip is hi-speed. \$\endgroup\$ – markrages Apr 15 '11 at 14:51
  • \$\begingroup\$ MMC mode is significantly slower than true SD-mode. \$\endgroup\$ – Adam Lawrence Apr 15 '11 at 16:26
  • \$\begingroup\$ Interesting - I had no idea that such a common IC could be so difficult to procure! Thank you for your feedback! \$\endgroup\$ – rascher Apr 20 '11 at 18:32

I've got the same question, and ended up finding this.

I've found the GL823 which (currently) costs about a quarter (USD; in qty 10) from LCSC. I even came across a simple schematic (none in the datasheet), which shows it to likely be a real one chip solution.


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