Product Overview The GL823K is a USB 2.0 single logical unit number (LUN) card reader controller that supports SD/MMC/MSPRO flash memory cards. It enables USB 2.0 high-speed transfers for Secure Digital (SD), SDHC, SDXC, miniSD, microSD (T-Flash), MultiMediaCard (MMC), Reduced-Size MultiMediaCard (RS MMC), MMCmicro, HS-MMC, MMCmobile, Memory Stick PRO (MS PRO), Memory Stick PRO Duo (MS PRO Duo), Memory Stick PRO-HG (MS PRO-HG), and MS Micro (M2). As a single-chip solution for USB 2.0 flash card readers, the GL823K complies with Universal Serial Bus Specification Revision 2.0, USB Mass Storage Class Specification Version 1.0, and each flash card interface specification. The GL823K integrates a high-speed 8051 microprocessor and an efficient hardware engine to achieve optimal data transfer performance between USB and flash card interfaces. Its pin assignment design is tailored for card slots, facilitating PCB layout. Internally, it incorporates a 5V-to-3.3V regulator, a 3.3V-to-1.8V regulator, power MOSFETs, and an on-chip clock source (OCCS) function, eliminating the need for an external 12MHz crystal oscillator and effectively reducing the overall bill of materials cost. The GL823K implements USB disconnect functionality and can be used for mobile cable/OTG reader/PC card reader applications.