LM8333
www.ti.com
SNLS246K –SEPTEMBER 2006–REVISED MAY 2013
LM8333 Mobile I/O Companion Supporting Key-Scan, I/O Expansion, PWM, and
ACCESS.bus Host Interface
Check for Samples: LM8333
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FEATURES
DESCRIPTION
The LM8333 Mobile I/O Companion offloads the
burden of keyboard scanning from the host, while
providing extremely low power consumption in both
operational and standby modes. It supports keypad
matrices up to 8 × 8 in size (plus another 8 special-
function keys), for portable applications such as
cellphones, PDAs, games, and other handheld
applications.
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8 × 8 Standard Keys
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8 Special Function Keys (SF Keys) Providing a
Total of 72 Keys for the Maximum Keyboard
Matrix
ACCESS.Bus (I2C-compatible) Communication
Interface to the Host
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Four General Purpose Host Programmable I/O
Pins with Two Optional (Slow) External
Interrupts
Key press and release events are encoded into a
byte format and loaded into a FIFO buffer for retrieval
by the host processor. An interrupt output (IRQ) is
used to signal events such as keypad activity, a state
change on either of two interrupt-capable general-
purpose I/O pins, or an error condition. Interrupt and
error codes are available to the host by reading
dedicated registers.
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15-byte FIFO Buffer to Store Key Pressed and
Key Released Events
Error Control with Error Reports on (FIFO
Overrun, Keypad Overrun, Invalid Command)
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Host Programmable PWM
Host Programmable Active Time and
Debounce Time
Four general-purpose I/O pins are available, two of
which have interrupt capability.
A
pulse-width
modulated output based on a host-programmable
internal timer is also available, which can be used as
a general-purpose output if the PWM function is not
required.
APPLICATIONS
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Mobile Phones
Personal Digital Assistants (PDAs)
Smart Handheld Devices
Personal Media Players
To minimize power, the LM8333 automatically enters
a low-power standby mode when there is no keypad,
I/O, or host activity.
The device is packaged in a 32–pin WQFN and a
49-pin csBGA. Both are chip-scale packages.
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PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
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