Glitch when trying to display a dash (ht16k33 7 segment LED backpack)

[Szabolcs2008]

Hi! I started working with the 7 segment display. I downloaded the tutorial code, and tried to display a "-" symbol.

But it turned out like this: (the other cables are for a temperature sensor and a fan) https://imgur.com/jLiU4ut

The code:

# SPDX-FileCopyrightText: 2019 Mikey Sklar for Adafruit Industries
#
# SPDX-License-Identifier: MIT

import time
import board
import busio
from adafruit_ht16k33 import segments

# Create the I2C interface.
i2c = busio.I2C(board.SCL, board.SDA)

# Create the LED segment class.
# This creates a 7 segment 4 character display:
display = segments.Seg7x4(i2c)

# Clear the display.
display.fill(0)

display.print("-")
time.sleep(0.5)

I fixed it with set_digit_raw and it seems like it uses a different binary code than the one specified in the program.

The working code (still the same tutorial code edit):

# SPDX-FileCopyrightText: 2019 Mikey Sklar for Adafruit Industries
#
# SPDX-License-Identifier: MIT

import time
import board
import busio
from adafruit_ht16k33 import segments

# Create the I2C interface.
i2c = busio.I2C(board.SCL, board.SDA)
# Create the LED segment class.
# This creates a 7 segment 4 character display:
display = segments.Seg7x4(i2c)

# Clear the display.
display.fill(0)

display.set_digit_raw(3, 0b01000000)
time.sleep(0.5)

[mikeysklar]

Thank you for pointing out the dash not printing and using the set_digit_raw() work around with the correct binary value.

I'll wire up my hardware and probably end up submitting a PR to the appropriate github repo (ht16k33 circuitpython library) if I find the same behavior.

Were you running this on a Raspberry Pi? Which mod of 7-segment display were you using? Was it the .56" height?

[mikeysklar]

I went ahead and loaded the code on a Pi4 using a .56" 7-seg display and was able to reproduce the same issue you are seeing. Based on the way the library has been re-written it makes more sense to use the set_digit_raw() as you have done.

Which guide did you find this code in? I'll go ahead and modify the dash usage.

[Szabolcs2008]

I used this guide:

https://learn.adafruit.com/matrix-7-segment-led-backpack-with-the-raspberry-pi/7-segment-test

[Szabolcs2008]

I found another error:

When i try to display a float type number, the part after the colon gets cut off (still using the code from the guide)

import time
import board
import busio
from adafruit_ht16k33 import segments

i2c = busio.I2C(board.SCL, board.SDA)

number = 36.45

display = segments.Seg7x4(i2c)
display.fill(0)

display.print(number)

result: https://imgur.com/e00LAPo

Fix: If i first convert it to a string with the str() function, it works fine

display.print(str(number))

result: https://imgur.com/ci7HCg3

[mikeysklar]

Thank you for your assistance with both issues. I've modified the example code sevensegment_test/code.py to not stumble over the '-' and to cast the floating point numbers to strings.

I've submitted a PR to the github repo so the replacement code should be up in the next day.