# Adafruit-hat-pwm

**URL:** <https://rpi-rgb-led-matrix.discourse.group/t/adafruit-hat-pwm/632>\
**Category:** Site Feedback\
**Created:** [March 14, 2023, 10:13am UTC](https://rpi-rgb-led-matrix.discourse.group/t/adafruit-hat-pwm/632 "2023-03-14T10:13:58Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![sehiyuk](https://avatars.discourse-cdn.com/v4/letter/s/77aa72/32.png) [@sehiyuk](https://rpi-rgb-led-matrix.discourse.group/u/sehiyuk)\
**Post date:** [March 14, 2023, 10:13am UTC](https://rpi-rgb-led-matrix.discourse.group/t/adafruit-hat-pwm/632/1 "2023-03-14T10:13:58Z")

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Dear Sir/Madam

Hello, firstly thank you a lot for such a great provided code. I face a problem when switching from " `-led-gpio-mapping=adafruit-hat`"mood to " `--led-gpio-mapping=adafruit-hat-pwm`."  
from MOSI I get a trigger to another device DMD and try to synchronize the frames displayed on DMD with LED PWM. in adafruit-hat mood, I face a brightness glitch just before my trigger and causing my image has flickering, so I connected GPIO 4 and 18 and change the mood to adafruit-hat-pwm and tried to run it. but unfortunately, i faced these errors:

![err](https://global.discourse-cdn.com/free1/uploads/rpi_rgb_led_matrix/original/1X/0578f55383e170a6cc7508393468b4f4166211ca.png)

when I searched on the internet I finally find I should update my raspberry to access \dev\ mem and dev\gpiomem but in further steps, I felt it may clear my library which is provided by this code. if anybody can help me what should I do?

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**Author:** ![marcmerlin](https://yyz2.discourse-cdn.com/free1/user_avatar/rpi-rgb-led-matrix.discourse.group/marcmerlin/32/40_2.png) [@marcmerlin](https://rpi-rgb-led-matrix.discourse.group/u/marcmerlin)\
**Post date:** [May 2, 2023, 3:47am UTC](https://rpi-rgb-led-matrix.discourse.group/t/adafruit-hat-pwm/632/2 "2023-05-02T03:47:39Z")

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not sure, but if you bought the hat from adafruit, have you asked them for support?