The MAX6955 is a compact display driver that interfaces
microprocessors to a mix of 7-segment, 14-segment,
and 16-segment LED displays through an I2C-compatible
2-wire serial interface. The MAX6955 drives up to 16
digits 7-segment, 8 digits 14-segment, 8 digits 16-segment,
or 128 discrete LEDs, while functioning from a
supply voltage as low as 2.7V. The driver includes five
I/O expander or general-purpose I/O (GPIO) lines, some
or all of which can be configured as a key-switch reader.
The key-switch reader automatically scans and
debounces a matrix of up to 32 switches.
Included on chip are full 14- and 16-segment ASCII
104-character fonts, a hexadecimal font for 7-segment
displays, multiplex scan circuitry, anode and cathode
drivers, and static RAM that stores each digit. The maximum
segment current for the display digits is set using
a single external resistor. Digit intensity can be independently
adjusted using the 16-step internal digital
brightness control. The MAX6955 includes a low-power
shutdown mode, a scan-limit register that allows the
user to display from 1 to 16 digits, segment blinking
(synchronized across multiple drivers, if desired), and a
test mode, which forces all LEDs on. The LED drivers
are slew-rate limited to reduce EMI.
For an SPI?-compatible version, refer to the MAX6954
data sheet. An evaluation kit (EV kit) for the MAX6955 is
available.
Applications
Set-Top Boxes Automotive
Panel Meters Bar Graph Displays
White Goods Audio/Video Equipment