MAX14500 Datasheet, PDF (26/41 Pages) Maxim Integrated Products – Hi-Speed USB-to-SD Card Readers with Bypass

Hi-Speed USB-to-SD Card
Readers with Bypass
RUNTIME
INTERRUPT ACTIVITY
NO
OCCURS
HAS
INTERRUPT STATUS
CHANGED?
NO
YES
• INTERRUPT STATUS
REGISTER BIT UPDATED
• INTERRUPT REQUEST
REGISTER BIT SET
INTERRUPT
REQUEST REGISTERS
READ?
YES
NO
NO
IS
INT ENABLED?
YES
CLEAR INT
IS INTERRUPT
MASK BIT
ENABLED?
YES
INT ENABLED-BASED
ON INTPULSE AND
INTACTHI FIELD SETTINGS
NOTE: THIS IS VALID FOR I²C CONTROL ONLY
Figure 12. Typical Interrupt Servicing Flowchart
Reset (RST)
Drive RST low to reset all the registers to the default
value and minimize the supply current.
Sleep
The MAX14500–MAX14503 can be put to sleep by pro-
gramming the WAKEUP bit to 0 in the control register
with I²C control, or by driving the MODE input low in
simple control. This turns off the internal microcontroller
to minimize current. Reads and writes to the I²C are still
functional, and registers can be updated with new val-
ues. Most register actions do not take effect until the
internal microcontroller wakes up or when Card Reader
mode is enabled. The SD port analog switches can
change states while the internal microcontroller is in
Sleep mode. The Register Map section shows which
registers are enabled in Sleep mode, at power-up, and
upon entering Card Reader mode.
Clock Configuration
The MAX14500–MAX14503 come preprogrammed to
accept a 12MHz, 13MHz, 19.2MHz, or 26MHz default
clock input with the clock squarer enabled for low-
amplitude TCXO signals (see the Ordering
Information/Selector Guide). This clock is used for the
USB and SD subsystems and is not required for opera-
tion of the I²C interface. This allows the clock frequency
to be changed in the system. The PLL subsystem con-
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