Free up memory to reduce Ethernet audio dropouts

[bharvey88]

Version: 26.9.18.1

What does this implement/fix?

The 64KB data cache came in from the Home Assistant Voice PE config, where it feeds microWakeWord. The CAST-1 has no microphone. On the S3 the cache is carved out of internal SRAM, so dropping to the IDF default of 32KB returns 32KB to the internal heap, the pool that runs short when streaming over Ethernet.

Tested on a CAST-1: 2 h 47 min of continuous streaming with no resets, and audio sounded clean throughout. Stream-start chunk drops were fewer than on 64KB (61 vs 84), with no drops or sync loss during steady playback.

Types of changes

• Bugfix (fixed change that fixes an issue)
• New feature (thanks!)
• Breaking change (repair/feature that breaks existing functionality)
• Dependency Update - Does not publish
• Other - Does not publish
• Website of github readme file update - Does not publish
• Github workflows - Does not publish

Checklist / Checklijst:

• The code change has been tested and works locally
• The code change has not yet been tested

If user-visible functionality or configuration variables are added/modified:

• Added/updated documentation for the web page

🤖 Generated with Claude Code

Summary by CodeRabbit

• Updates
  • Updated the firmware version to 26.9.18.1.
  • Adjusted ESP32-S3 data cache allocation from 64 KB to 32 KB.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Advanced

Run ID: e0d89db9-e7b1-405b-8ed7-b43789ff1a19

📥 Commits

Reviewing files that changed from the base of the PR and between 1ccc1b3 and 55cd8a6.

📒 Files selected for processing (1)

• Integrations/ESPHome/Core.yaml

Included review availability: Your plan provides up to 1 included review per hour; 0 remain after this review.

---

Walkthrough

The ESPHome configuration updates the firmware version substitution and changes the ESP32-S3 data cache setting from 64KB to 32KB.

Changes

ESPHome configuration

Layer / File(s)	Summary
Firmware and cache settings Integrations/ESPHome/Core.yaml	The firmware version changes from 26.8.28.1 to 26.9.18.1. The ESP32-S3 data cache changes from 64KB to 32KB.

Priority: ⬇️ Low

Estimated code review effort: 1 (Trivial) | ~5 minutes

Change: Bug fix

Suggested reviewers: bunton33

Merge Risk: ⚪ Minimal · up to 55cd8

The configuration update matches the stated objective and supplied streaming validation, with no actionable merge-blocking risk remaining.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 0…
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly describes the main change: reducing memory use to improve Ethernet audio streaming reliability.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Commit to this branch
• Create a new PR

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{A rabbit checks the version line,
The cache now fits a smaller design.
ESPHome hops with settings bright,
Firmware numbers land just right.
Two small changes cross the field,
A tidy configuration yield.}

_{Comment @coderabbitai help to get the list of available commands.}