HT16K33 4-Digit 7-Segment Display

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Overview

A 4-digit 7-segment display using the HT16K33 chipset. It uses I2C interface.

Specifications

Onboard HT16K33 LED Controller
I2C interface
1/16-step display dimming
I2C address jumper selectable from 0x70 to 0x77

Supported GPIO

Raspberry Pi 0~4
Raspberry Pi 5
BeagleBone Black/Green
Jetson Nano
FT232H, FT2232H, FT4232H
MCP2221

Commands

[PRINT_TEXT]

Sets text on the display. Some characters may not be displayable. You must execute the WRITE_DISPLAY command after setting to show it on the display.

Item	Type	Description
Text	WRITE	Enter the text to set.

[PRINT_NUM]

Sets numbers on the display. Negative numbers and decimal points are also supported. You must execute the WRITE_DISPLAY command after setting to show it on the display.

Item	Type	Description
Number	WRITE	Enter the number to set.
Decimal Places	WRITE	Set how many decimal places to display. (0~3)

[PRINT_DATE]

Sets date on the display in “Year.Month” or “Month.Day” format. You must execute the WRITE_DISPLAY command after setting to show it on the display.

Item	Type	Description
Date	WRITE	Enter the date to set.
Display Content	WRITE	Select the content to display. (Year/Month, Month/Day)
Show Dot (.)	WRITE	Set whether to display a dot (.) between Year/Month or Month/Day.

[PRINT_CLOCK]

Sets time on the display in “Hour:Minute” or “Minute:Second” format. You must execute the WRITE_DISPLAY command after setting to show it on the display.

Item	Type	Description
Time	WRITE	Enter the time to set.
Display Content	WRITE	Select the content to display. (Hour/Minute, Minute/Second)
Show Colon (:)	WRITE	Set whether to display a colon (:) between Hour/Minute or Minute/Second.

[PRINT_TIME]

Sets time duration on the display in “Hour:Minute” or “Minute:Second” format. If time exceeds 99 hours, it will be displayed as 99 hours. You must execute the WRITE_DISPLAY command after setting to show it on the display.

Item	Type	Description
Time Duration	WRITE	Enter the time duration to set.
Display Content	WRITE	Select the content to display. (Hour/Minute, Minute/Second)
Show Colon (:)	WRITE	Set whether to display a colon (:) between Hour/Minute or Minute/Second.

[WRITE_DIGIT_NUM]

Sets a number at a specific position on the display. You must execute the WRITE_DISPLAY command after setting to show it on the display.

Item	Type	Description
Position (0~3)	WRITE	Set the position to display the number. (0 from leftmost)
Number (0~9)	WRITE	Enter the number to display. (0~9)
Show Dot (.)	WRITE	Set whether to display a dot (.) after the number.

[WRITE_DIGIT_ASCII]

Sets a character corresponding to ASCII code at a specific position on the display. Some characters may not be displayable. You must execute the WRITE_DISPLAY command after setting to show it on the display.

Item	Type	Description
Position (0~3)	WRITE	Set the position to display the character. (0 from leftmost)
ASCII Code	WRITE	Enter the character to display as ASCII code.
Show Dot (.)	WRITE	Set whether to display a dot (.) after the character.

[DRAW_COLON]

Sets whether to display the colon (:) on the display. You must execute the WRITE_DISPLAY command after setting to show it on the display.

Item	Type	Description
Show Colon (:)	WRITE	Set whether to display the colon (:).

[WRITE_DIGIT_RAW]

Sets a byte value configured as bitmask at a specific position on the display. You must execute the WRITE_DISPLAY command after setting to show it on the display.

Item	Type	Description
Position (0~4)	WRITE	Set the position to display the bitmask value. Includes the colon (:) position. (0 from leftmost)
BITMASK *	WRITE	Enter the bitmask value to display at that position.

* Refer to the following to calculate the bitmask value. Values marked with X are not used, so enter 0. Example) To display 8: Binary 0b01111111 → Hexadecimal 0x7F → Decimal 127

To display colon (:), enter 0x02 (decimal 2); to not display, enter 0x00 (decimal 0).

[WRITE_DISPLAY]

Actually displays the configured content on the display.

[CLEAR]

Clears all configured content. You must execute the WRITE_DISPLAY command after setting to reflect it on the display.

[SET_BRIGHTNESS]

Sets the brightness of the display.

Item	Type	Description
Brightness	WRITE	Set the brightness of the display. (0~15)

[BLINK_RATE]

Sets the blink rate of the display.

Item	Type	Description
Blink Rate	WRITE	Set the display blink rate. (None, Twice per second, Once per second, Once every 2 seconds)

Example

Objective

Display the current time on the display in “Hour:Minute” format with the colon (:) blinking once per second.

Parts

Part	Quantity
Raspberry Pi 4 *	1
HT16K33 Display	1

* Other hardware can also be used. Refer to Supported GPIO.

Wiring

Connect the following pins horizontally to each other.

HT16K33 Display	GPIO
VIN	3.3V
GND	GND
SCL (C)	3 (I2C1 SCL)
SDA (D)	2 (I2C1 SDA)

Project Link

References

Datasheet

Library