6

Electrical Description

Pin Function

Description

RESET (RST) 

Sets Control Register bits to logic low. The Dot Register contents are unaffected by 

the Reset pin. (logic low = reset; logic high = normal operation).

Serial Data input for Dot or Control Register data. Data is entered on the rising edge 

of the Clock input.

Serial Data output for Dot or Control Register data. This pin is used for cascading 

multiple displays.

CLOCK (CLK) 

Clock input for writing Dot or Control Register data. When Chip Enable is logic low, 

data is entered on the rising Clock edge.

REGISTER SELECT (RS) 

Selects Dot Register (RS = logic low) or Control Register (RS = logic high) as the  des-

tination for serial data entry. The logic level of RS is latched on the falling edge of the 

Chip Enable input.

CHIP ENABLE (CE) 

This input must be a logic low to write data to the display. When CE returns to logic 

high and CLK is logic low, data is latched to either the LED output drivers or a Control 

Register.

OSCILLATOR SELECT (SEL) 

Selects either an internal or external display oscillator source. (logic low = External 

Display Oscillator; logic high = Internal Display Oscillator).

OSCILLATOR (OSC) 

Output for the Internal Display Oscillator (SEL = logic high) or input for an External 

Display Oscillator (SEL = logic low).

BLANK (BL) 

Blanks the display when logic high. May be modulated for brightness control.

Ground for LED drivers.

Ground for logic.

Positive supply for LED drivers.

Positive supply for logic.

Peak

Dominant

Wavelength

Wavelength

Character Average (µcd)

Display Color

Part Number

Min.

Typ.

Typ.

Typ.

AlGaAs Red  

HCMS-29X5 

95 

230 

645 

637

High Efficiency Red 

HCMS-29X2 

29 

64 

635 

626

Orange 

HCMS-29X4 

29 

64 

600 

602

Yellow 

HCMS-29X1 

29 

64 

583 

585

Green 

HCMS-29X3 

57 

114 

568 

574

Notes:

1.  Refers to the initial case temperature of the device immediately prior to measurement.

2.  Measured with all LEDs illuminated.

LED color.