Fixing random mute/unmute on certain Arduino's (Tested Arduino Nano U…

[acekrystal]

…SB-C)

Issues

• Fixes Random mute/unmute or volume jump when turning encoder. #249
• Resolves #
• Closes #
• Potential Fixes Disconnected after standby and no reconnection after wake-up #208 and Device Disconnects and only reconnects after unplugged for 5-10 minutes #243

Description

Changing Baud Rate 115600 to 76800 as 115600 seems to be unflavored by the Atmega328P chip datasheet for common arduino configurations.

Types of changes

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• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation Update (if none of the other choices apply)

Checklist

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• Requested changes are in a branch
• Compiled and tested requested changes on target hardware (PC, device)
• Updated the documentation, if necessary
• Updated the LICENSES file, if necessary
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Further comments

Fixing unexpected behavior of certain Arduino (clone?) boards where volume would glitch random value's or would randomly mute/unmute when turning the encoder.

This update might also increasing serial reliability for most other Atmega 328P boards.

Debugging the Glitches on an Arduino Nano (USB-C) clone it turns out either upping or lowering the boad rate to certain (common) rate would fix the problem. Digging into why this is the case revealed in many online conversations with the Atmega 328P datasheet backing this up that a baud rate of 115200 seems to be unfavored for the 328P chip in common configurations seen by Arduino boards. This baud rate matches difficult with the arduino configured 328P chip that it uses all correction/recovery potential in order to establish a working connection. When hardware deviations are added on top (for example a cheap 16Mhz Crystal running slightly slower) this could just tip over the correction capability and would result in faulty communications.

Looking at the datasheet the closest speed to 115200 with a great clock speed alignmet would be 76800 for a wide range of clock speed (8Mhz,12Mhz,16Mhz,18Mhz,20Mhz).
So the use of a 76800 baud rate leaves much more room to correct for cheap and unstable hardware situations.