Features
Key Features
| • |
Supports keypad matrices of up to 8 × 12 keys plus 8 special-function (SF) keys for a total of 104 keys. SF keys pull keypad
scan inputs directly to ground, rather than connecting to a keypad scan output.
|
| • |
Supports I
2C-compatible ACCESS.bus interface in slave mode up to 400 kHz (Fast-mode).
|
| • |
Three host-programmable PWM outputs useful for smooth LED brightness modulation.
|
| • |
Supports general-purpose I/O expansion on pins not otherwise used for keypad interface.
|
| • |
Key-scan event storage in a FIFO buffer for up to 15 events.
|
| • |
Key events, errors, and dedicated hardware interrupts request host service by asserting the
^IRQ output.
|
| • |
The correct reception of a command may be assumed, if no error is reported from the LM8322 after receiving a command.
|
| • |
Wake-up from Halt mode on any matrix key-scan event, any use of the SF keys, or any activity on the ACCESS.bus interface.
|
General Description
The LM8322 Mobile I/O Companion is a dedicated device to unburden a host processor from scanning a matrix-addressed keypad.
In addition, the LM8322 provides general-purpose
I/O expansion, and PWM outputs useful for dynamic LED brightness modulation.
It communicates with the host through an I
2C-compatible ACCESS.bus interface. More...
Applications
| • |
Mobile phones
|
| • |
Personal Digital Assistants (PDAs)
|
| • |
Smart handheld devices
|
| • |
Personal media players
|
| |
Typical Application
*click for larger image
| Parameters | Values |
|---|
| Input Min Voltage |
1.62 Volt |
| Input Max Voltage |
1.98 Volt |
| Max Keypad |
104 |
| Special Function Keys |
8 |
| Key Debounce |
Yes |
| GPIOs |
16, Multiplexed |
| External Interrupts |
0 |
| Host Interface Type |
Access Bus/I2C |
| Host Interface Bus Speed |
400000 Hz |
| Special Features |
PWM outputs are multiplexed |
| Access BUS/I2C Address |
4 |
| Watchdog |
Yes |
| FIFO Buffer |
16 Bytes |
| PWM Outputs |
3 |
| Wakeup |
Yes |
| On-Chip Oscillator |
Yes |
| External Clock Input |
Yes |
| On-Chip Power-on-Reset |
Yes |
| RegType |
Mobile IO Companion |
| Temperature Min |
-40 deg C |
| Temperature Max |
85 deg C |
| |
Also Recommended
| LM8333▲ | 2.5 V Operation, Up To 72 Keys, 4 GPIO, LLP Package |
Additional Resources
Design Tools
Block Diagram
*click for larger image
|
RoHS Compliance Information
