MAX14502AETL+T Maxim Integrated Products, MAX14502AETL+T Datasheet - Page 21

• Manufacturer Part Number: MAX14502AETL+T
• Description: IC CARD READER USB-SD 40-TQFN
• Manufacturer: Maxim Integrated Products

Specifications of MAX14502AETL+T

• Applications: USB
• Interface: I²C
• Voltage - Supply: 1.8 V ~ 3.3 V
• Package / Case: 40-TQFN Exposed Pad
• Mounting Type: Surface Mount
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

When the card reader is initiated in the control register,
the internal USB switch disconnects from the host µP
USB port and connects to the internal USB Hi-Speed
SD card reader unit. When the MAX14500–MAX14503
disconnect from the host to implement a stand-alone
high-speed card reader, it simulates a disconnect on
the host USB and SD ports to maintain data coherence.
The SD connections are restored to the host µP by clos-
ing the analog switch connecting CCRD_PRST to
HCRD_PRST.
Certain registers execute actions when entering Card
Reader mode. These actions are only valid for Card
Reader mode. Writing to these registers in Sleep mode,
or when awake, updates the registers, but the action is
Figure 8. Card Reader Mode. The USB port is connected to SD card 1. In the 2 port version, a second SD card (SD slot 2) can be
independently connected and disconnected to the host µP.
CONNECTOR
USB
SLOT2
SLOT1
SD
SD
______________________________________________________________________________________
D+
D-
4
4
CCLK2
CCMD2
CDAT2_[3:0]
CCRD_PRST
CCLK1
CCMD1
CDAT1_[3:0]
CD+
CD-
TRANSCEIVER
SD CARD INTERFACE
USB
CARD READER
USB HS
USB SWITCHES
SD PORT 2 SWITCHES
Hi-Speed USB-to-SD Card
MAX14500–
MAX14503
carried out when Card Reader mode is activated for
one of the SD cards (see the Register Map section).
When Card Reader mode is initially entered, the internal
microcontroller enumerates with the PC to establish a
high-speed USB mass storage device. No actions by the
host µP are required for enumeration other than entering
Card Reader mode. Once the USB-SD card connection
is established, PC to SD card data transfer begins and
various interrupts monitor the status the of Card Reader
mode if enabled. The BSY flag is represented externally
by the BUSY output and can be read serially through
I
requests Sleep mode in the middle of the data transfer,
the MAX14500–MAX14503 do not complete the transfer,
exit Card Reader mode, reconnect USB switches, and
2
SD PORT 1 SWITCHES
C. The BUSY output is always active. If the host µP
Readers with Bypass
HDAT2_[3:0]
HCRD_PRST
HDAT1_[3:0]
HCMD2
HCMD1
HCLK2
HCLK1
HD+
HD-
4
4
PORT2
PORT1
HOST
USB
SD
SD
HOST PROCESSOR
I/O
21