Files
HaloKeymind/esp32_memory_budget/index.html
T
2026-09-15 05:34:40 +00:00

2995 lines
43 KiB
HTML

<!doctype html>
<html lang="en" class="no-js">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width,initial-scale=1">
<meta name="description" content="Documentation for the open source MeshCore firmware">
<link rel="canonical" href="https://mikecarper.github.io/MeshCore/esp32_memory_budget/">
<link rel="prev" href="../double_frequency_v4_validation/">
<link rel="next" href="../espnow_bridge_setup/">
<link rel="icon" href="../assets/images/favicon.png">
<meta name="generator" content="mkdocs-1.6.1, mkdocs-material-9.7.7">
<title>Classic ESP32 image memory budget - MeshCore Docs</title>
<link rel="stylesheet" href="../assets/stylesheets/main.ec1eaa64.min.css">
<link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
<link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Roboto:300,300i,400,400i,700,700i%7CRoboto+Mono:400,400i,700,700i&display=fallback">
<style>:root{--md-text-font:"Roboto";--md-code-font:"Roboto Mono"}</style>
<link rel="stylesheet" href="../_stylesheets/extra.css">
<link rel="stylesheet" href="../_stylesheets/firmware_picker.css">
<link rel="stylesheet" href="../_stylesheets/telemetry_decoder.css">
<link rel="stylesheet" href="../_stylesheets/filter_tool.css">
<script>__md_scope=new URL("..",location),__md_hash=e=>[...e].reduce(((e,_)=>(e<<5)-e+_.charCodeAt(0)),0),__md_get=(e,_=localStorage,t=__md_scope)=>JSON.parse(_.getItem(t.pathname+"."+e)),__md_set=(e,_,t=localStorage,a=__md_scope)=>{try{t.setItem(a.pathname+"."+e,JSON.stringify(_))}catch(e){}}</script>
</head>
<body dir="ltr">
<input class="md-toggle" data-md-toggle="drawer" type="checkbox" id="__drawer" autocomplete="off">
<input class="md-toggle" data-md-toggle="search" type="checkbox" id="__search" autocomplete="off">
<label class="md-overlay" for="__drawer"></label>
<div data-md-component="skip">
<a href="#classic-esp32-image-memory-budget" class="md-skip">
Skip to content
</a>
</div>
<div data-md-component="announce">
</div>
<header class="md-header md-header--shadow" data-md-component="header">
<nav class="md-header__inner md-grid" aria-label="Header">
<a href=".." title="MeshCore Docs" class="md-header__button md-logo" aria-label="MeshCore Docs" data-md-component="logo">
<img src="../_assets/meshcore.svg" alt="logo">
</a>
<label class="md-header__button md-icon" for="__drawer">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M3 6h18v2H3zm0 5h18v2H3zm0 5h18v2H3z"/></svg>
</label>
<div class="md-header__title" data-md-component="header-title">
<div class="md-header__ellipsis">
<div class="md-header__topic">
<span class="md-ellipsis">
MeshCore Docs
</span>
</div>
<div class="md-header__topic" data-md-component="header-topic">
<span class="md-ellipsis">
Classic ESP32 image memory budget
</span>
</div>
</div>
</div>
<script>var palette=__md_get("__palette");if(palette&&palette.color){if("(prefers-color-scheme)"===palette.color.media){var media=matchMedia("(prefers-color-scheme: light)"),input=document.querySelector(media.matches?"[data-md-color-media='(prefers-color-scheme: light)']":"[data-md-color-media='(prefers-color-scheme: dark)']");palette.color.media=input.getAttribute("data-md-color-media"),palette.color.scheme=input.getAttribute("data-md-color-scheme"),palette.color.primary=input.getAttribute("data-md-color-primary"),palette.color.accent=input.getAttribute("data-md-color-accent")}for(var[key,value]of Object.entries(palette.color))document.body.setAttribute("data-md-color-"+key,value)}</script>
<label class="md-header__button md-icon" for="__search">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M9.5 3A6.5 6.5 0 0 1 16 9.5c0 1.61-.59 3.09-1.56 4.23l.27.27h.79l5 5-1.5 1.5-5-5v-.79l-.27-.27A6.52 6.52 0 0 1 9.5 16 6.5 6.5 0 0 1 3 9.5 6.5 6.5 0 0 1 9.5 3m0 2C7 5 5 7 5 9.5S7 14 9.5 14 14 12 14 9.5 12 5 9.5 5"/></svg>
</label>
<div class="md-search" data-md-component="search" role="dialog">
<label class="md-search__overlay" for="__search"></label>
<div class="md-search__inner" role="search">
<form class="md-search__form" name="search">
<input type="text" class="md-search__input" name="query" aria-label="Search" placeholder="Search" autocapitalize="off" autocorrect="off" autocomplete="off" spellcheck="false" data-md-component="search-query" required>
<label class="md-search__icon md-icon" for="__search">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M9.5 3A6.5 6.5 0 0 1 16 9.5c0 1.61-.59 3.09-1.56 4.23l.27.27h.79l5 5-1.5 1.5-5-5v-.79l-.27-.27A6.52 6.52 0 0 1 9.5 16 6.5 6.5 0 0 1 3 9.5 6.5 6.5 0 0 1 9.5 3m0 2C7 5 5 7 5 9.5S7 14 9.5 14 14 12 14 9.5 12 5 9.5 5"/></svg>
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M20 11v2H8l5.5 5.5-1.42 1.42L4.16 12l7.92-7.92L13.5 5.5 8 11z"/></svg>
</label>
<nav class="md-search__options" aria-label="Search">
<button type="reset" class="md-search__icon md-icon" title="Clear" aria-label="Clear" tabindex="-1">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M19 6.41 17.59 5 12 10.59 6.41 5 5 6.41 10.59 12 5 17.59 6.41 19 12 13.41 17.59 19 19 17.59 13.41 12z"/></svg>
</button>
</nav>
<div class="md-search__suggest" data-md-component="search-suggest"></div>
</form>
<div class="md-search__output">
<div class="md-search__scrollwrap" tabindex="0" data-md-scrollfix>
<div class="md-search-result" data-md-component="search-result">
<div class="md-search-result__meta">
Initializing search
</div>
<ol class="md-search-result__list" role="presentation"></ol>
</div>
</div>
</div>
</div>
</div>
<div class="md-header__source">
<a href="https://github.com/mikecarper/MeshCore/" title="Go to repository" class="md-source" data-md-component="source">
<div class="md-source__icon md-icon">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!--! Font Awesome Free 7.1.0 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2025 Fonticons, Inc.--><path d="M439.6 236.1 244 40.5c-5.4-5.5-12.8-8.5-20.4-8.5s-15 3-20.4 8.4L162.5 81l51.5 51.5c27.1-9.1 52.7 16.8 43.4 43.7l49.7 49.7c34.2-11.8 61.2 31 35.5 56.7-26.5 26.5-70.2-2.9-56-37.3L240.3 199v121.9c25.3 12.5 22.3 41.8 9.1 55-6.4 6.4-15.2 10.1-24.3 10.1s-17.8-3.6-24.3-10.1c-17.6-17.6-11.1-46.9 11.2-56v-123c-20.8-8.5-24.6-30.7-18.6-45L142.6 101 8.5 235.1C3 240.6 0 247.9 0 255.5s3 15 8.5 20.4l195.6 195.7c5.4 5.4 12.7 8.4 20.4 8.4s15-3 20.4-8.4l194.7-194.7c5.4-5.4 8.4-12.8 8.4-20.4s-3-15-8.4-20.4"/></svg>
</div>
<div class="md-source__repository">
mikecarper/MeshCore
</div>
</a>
</div>
</nav>
</header>
<div class="md-container" data-md-component="container">
<main class="md-main" data-md-component="main">
<div class="md-main__inner md-grid">
<div class="md-sidebar md-sidebar--primary" data-md-component="sidebar" data-md-type="navigation" >
<div class="md-sidebar__scrollwrap">
<div class="md-sidebar__inner">
<nav class="md-nav md-nav--primary" aria-label="Navigation" data-md-level="0">
<label class="md-nav__title" for="__drawer">
<a href=".." title="MeshCore Docs" class="md-nav__button md-logo" aria-label="MeshCore Docs" data-md-component="logo">
<img src="../_assets/meshcore.svg" alt="logo">
</a>
MeshCore Docs
</label>
<div class="md-nav__source">
<a href="https://github.com/mikecarper/MeshCore/" title="Go to repository" class="md-source" data-md-component="source">
<div class="md-source__icon md-icon">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!--! Font Awesome Free 7.1.0 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2025 Fonticons, Inc.--><path d="M439.6 236.1 244 40.5c-5.4-5.5-12.8-8.5-20.4-8.5s-15 3-20.4 8.4L162.5 81l51.5 51.5c27.1-9.1 52.7 16.8 43.4 43.7l49.7 49.7c34.2-11.8 61.2 31 35.5 56.7-26.5 26.5-70.2-2.9-56-37.3L240.3 199v121.9c25.3 12.5 22.3 41.8 9.1 55-6.4 6.4-15.2 10.1-24.3 10.1s-17.8-3.6-24.3-10.1c-17.6-17.6-11.1-46.9 11.2-56v-123c-20.8-8.5-24.6-30.7-18.6-45L142.6 101 8.5 235.1C3 240.6 0 247.9 0 255.5s3 15 8.5 20.4l195.6 195.7c5.4 5.4 12.7 8.4 20.4 8.4s15-3 20.4-8.4l194.7-194.7c5.4-5.4 8.4-12.8 8.4-20.4s-3-15-8.4-20.4"/></svg>
</div>
<div class="md-source__repository">
mikecarper/MeshCore
</div>
</a>
</div>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href=".." class="md-nav__link">
<span class="md-ellipsis">
Introduction
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../WiFi/" class="md-nav__link">
<span class="md-ellipsis">
WiFi and MQTT by Firmware Type
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../cad_scan_validation/" class="md-nav__link">
<span class="md-ellipsis">
SX1262 channel-scanning hardware results
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../carrier_wave/" class="md-nav__link">
<span class="md-ellipsis">
Carrier-wave RF checks
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../carrier_wave_validation/" class="md-nav__link">
<span class="md-ellipsis">
CW and CW2 validation
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../cli_build_matrix/" class="md-nav__link">
<span class="md-ellipsis">
CLI Availability by Firmware Build
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../cli_command_availability/" class="md-nav__link">
<span class="md-ellipsis">
CLI Command Availability Matrix
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../cli_commands/" class="md-nav__link">
<span class="md-ellipsis">
CLI Commands
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../cli_settings_audit/" class="md-nav__link">
<span class="md-ellipsis">
CLI setting dispatch audit
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../companion_contact_cache/" class="md-nav__link">
<span class="md-ellipsis">
Full Companion contact caches
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../companion_contact_cache_results/" class="md-nav__link">
<span class="md-ellipsis">
Contact-cache and NimBLE RAM qualification
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../companion_offline_queue/" class="md-nav__link">
<span class="md-ellipsis">
Companion Offline Message Queue
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../companion_protocol/" class="md-nav__link">
<span class="md-ellipsis">
Companion Protocol
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../companion_radio_full/" class="md-nav__link">
<span class="md-ellipsis">
Full Companion
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../companion_usb_ascii_validation/" class="md-nav__link">
<span class="md-ellipsis">
USB Companion ASCII default validation
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../companion_usb_client_validation/" class="md-nav__link">
<span class="md-ellipsis">
USB Companion client compatibility
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../docs/" class="md-nav__link">
<span class="md-ellipsis">
Local Documentation
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../double_frequency_v4_validation/" class="md-nav__link">
<span class="md-ellipsis">
Double center-frequency write: V4 transmitter / XIAO receiver
</span>
</a>
</li>
<li class="md-nav__item md-nav__item--active">
<input class="md-nav__toggle md-toggle" type="checkbox" id="__toc">
<label class="md-nav__link md-nav__link--active" for="__toc">
<span class="md-ellipsis">
Classic ESP32 image memory budget
</span>
<span class="md-nav__icon md-icon"></span>
</label>
<a href="./" class="md-nav__link md-nav__link--active">
<span class="md-ellipsis">
Classic ESP32 image memory budget
</span>
</a>
<nav class="md-nav md-nav--secondary" aria-label="Table of contents">
<label class="md-nav__title" for="__toc">
<span class="md-nav__icon md-icon"></span>
Table of contents
</label>
<ul class="md-nav__list" data-md-component="toc" data-md-scrollfix>
<li class="md-nav__item">
<a href="#build-enforcement" class="md-nav__link">
<span class="md-ellipsis">
Build enforcement
</span>
</a>
</li>
<li class="md-nav__item">
<a href="#boot-versus-running-memory" class="md-nav__link">
<span class="md-ellipsis">
Boot versus running memory
</span>
</a>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item">
<a href="../espnow_bridge_setup/" class="md-nav__link">
<span class="md-ellipsis">
ESP-NOW bridge: simple setup
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../faq/" class="md-nav__link">
<span class="md-ellipsis">
Frequently Asked Questions
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../filter_tool/" class="md-nav__link">
<span class="md-ellipsis">
Filter policy playground
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../firmware_memory_budget/" class="md-nav__link">
<span class="md-ellipsis">
Firmware memory checks
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../firmware_picker/" class="md-nav__link">
<span class="md-ellipsis">
Firmware picker
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../flood_filtering/" class="md-nav__link">
<span class="md-ellipsis">
Flood Filtering and Moderation
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../four_fixed_tx_dwell_validation/" class="md-nav__link">
<span class="md-ellipsis">
Four fixed transmitters: longer dwell repeats
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../four_fixed_tx_single_pass_validation/" class="md-nav__link">
<span class="md-ellipsis">
Four fixed transmitters / fast single-pass receiver
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../full_companion_features/" class="md-nav__link">
<span class="md-ellipsis">
Full Companion: turn features on and off
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../full_companion_usb_switcher/" class="md-nav__link">
<span class="md-ellipsis">
Companion USB CLI and binary switcher
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../full_usb_logging_validation/" class="md-nav__link">
<span class="md-ellipsis">
Full USB logging repair — 1.17.1.6
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../gps_tracking/" class="md-nav__link">
<span class="md-ellipsis">
GPS Tracking
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../halo_keymind_settings/" class="md-nav__link">
<span class="md-ellipsis">
Halo and Keymind Branch Settings
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../hardware_validation_bluetooth_stealth_2026-09-07/" class="md-nav__link">
<span class="md-ellipsis">
XIAO Bluetooth stealth hardware validation - 2026-09-07
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../hardware_validation_checklist/" class="md-nav__link">
<span class="md-ellipsis">
Hardware validation checklist
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../home_text_spacing/" class="md-nav__link">
<span class="md-ellipsis">
Home-screen text spacing
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../host_cli_service/" class="md-nav__link">
<span class="md-ellipsis">
LoRa CLI Host Service
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../kiss_modem_protocol/" class="md-nav__link">
<span class="md-ellipsis">
MeshCore KISS Modem Protocol
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../lora_ota_automation/" class="md-nav__link">
<span class="md-ellipsis">
Scripted LoRa OTA from start to finish
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../mbedtls-tls-footprint/" class="md-nav__link">
<span class="md-ellipsis">
Shrinking the per-connection TLS footprint on non-PSRAM observers
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../mixed_scan_validation/" class="md-nav__link">
<span class="md-ellipsis">
Mixed-bandwidth two-channel reception test
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../mixed_sf_bw_validation/" class="md-nav__link">
<span class="md-ellipsis">
Equal-symbol-time mixed SF/BW, four-channel test
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../nimble_companion_trial/" class="md-nav__link">
<span class="md-ellipsis">
ESP32-S3 NimBLE Full Companion trial
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../nimble_companion_trial_results/" class="md-nav__link">
<span class="md-ellipsis">
ESP32-S3 NimBLE trial results, 2026-09-08
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../nrf52-usb-ready-fix/" class="md-nav__link">
<span class="md-ellipsis">
nRF52 USB READY hang
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../nrf52_companion_storage_recovery/" class="md-nav__link">
<span class="md-ellipsis">
nRF52 Companion automatic ExtraFS recovery
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../nrf52_power_management/" class="md-nav__link">
<span class="md-ellipsis">
nRF52 Power Management
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../number_allocations/" class="md-nav__link">
<span class="md-ellipsis">
Number Allocations
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../ota_easy/" class="md-nav__link">
<span class="md-ellipsis">
Easy firmware updates over LoRa
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../ota_meshtower_v2_sdcard/" class="md-nav__link">
<span class="md-ellipsis">
MeshTower V2 microSD LoRa OTA
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../ota_nrf52_bootloader_update/" class="md-nav__link">
<span class="md-ellipsis">
nRF52 bootloader updates over LoRa
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../ota_nrf52_qspi/" class="md-nav__link">
<span class="md-ellipsis">
nRF52 repeater LoRa OTA with external QSPI
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../ota_protocol/" class="md-nav__link">
<span class="md-ellipsis">
MeshCore OTA - .mota container &amp; LoRa protocol
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../ota_user_guide/" class="md-nav__link">
<span class="md-ellipsis">
Updating your node over the air (OTA) - user guide
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../packet_format/" class="md-nav__link">
<span class="md-ellipsis">
Packet Format
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../pair_4p6_300us_validation/" class="md-nav__link">
<span class="md-ellipsis">
SF7/62.5 + SF8/500: 4.6 slow chirps, 0.3 ms reserve
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../pair_preamble32_validation/" class="md-nav__link">
<span class="md-ellipsis">
SF7/62.5 + SF8/500, fast switching and preamble 32
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../payloads/" class="md-nav__link">
<span class="md-ellipsis">
Payload Format
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../pr7_review_validation/" class="md-nav__link">
<span class="md-ellipsis">
PR #7 review and validation
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../preamble_detection_investigation/" class="md-nav__link">
<span class="md-ellipsis">
Off-channel preamble investigation
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../qr_codes/" class="md-nav__link">
<span class="md-ellipsis">
QR Codes
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../radio_chirp_math_validation/" class="md-nav__link">
<span class="md-ellipsis">
Shared radio/radio2 chirp timing and preamble warnings
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../radio_dwell_policy_validation/" class="md-nav__link">
<span class="md-ellipsis">
Automatic dwell policy: 4.6 chirps on both profiles
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../radio_profile_switch_validation/" class="md-nav__link">
<span class="md-ellipsis">
SX1262 profile-switch validation
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../radio_profiles/" class="md-nav__link">
<span class="md-ellipsis">
Two LoRa profiles on one radio
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../radio_profiles_validation/" class="md-nav__link">
<span class="md-ellipsis">
Dual-profile receive validation
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../radio_receive_calibration/" class="md-nav__link">
<span class="md-ellipsis">
Radio receive calibration and recovery
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../rak3401_mota_chain/" class="md-nav__link">
<span class="md-ellipsis">
RAK3401 1W repeater compact LoRa update chain
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../role_feature_switches/" class="md-nav__link">
<span class="md-ellipsis">
Feature switches by role — 1.17.1.5 USA Cascade
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../s3_memory_soak_validation/" class="md-nav__link">
<span class="md-ellipsis">
ESP32-S3 OTA memory experiment
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../separated_radio_modulation_cache_validation/" class="md-nav__link">
<span class="md-ellipsis">
Separated radios, normal XIAO RX gain, and unchanged-modulation timing
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../sf10_10_vs_100hz_full_sample_validation/" class="md-nav__link">
<span class="md-ellipsis">
SF10/125 full samples: 10 Hz versus 100 Hz first-pass detour
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../sf10_10hz_cr_detour_validation/" class="md-nav__link">
<span class="md-ellipsis">
SF10/125: tiny first-pass frequency offset and coding-rate detour
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../sf10_full_retune_twice_validation/" class="md-nav__link">
<span class="md-ellipsis">
SF10/125: apply the full radio settings twice per hop
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../sf10_nrf52_double_write_settling_validation/" class="md-nav__link">
<span class="md-ellipsis">
SF10 / 125 kHz, XIAO nRF52 TX, double write, 1 ms delay grid
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../sf10_rollback_failure_validation/" class="md-nav__link">
<span class="md-ellipsis">
SF10/125 rollback and wider-spacing failure isolation
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../sf125_settling_limits_validation/" class="md-nav__link">
<span class="md-ellipsis">
Descending SF10..SF5 / 125 kHz settling limits
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../sf5_250_dwell_validation/" class="md-nav__link">
<span class="md-ellipsis">
SF5 / 250 kHz: four-channel dwell sweep
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../sf6_125_settling_validation/" class="md-nav__link">
<span class="md-ellipsis">
SF6/125 four-channel post-switch settling sweep
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../sf6_5p1_trace_validation/" class="md-nav__link">
<span class="md-ellipsis">
SF6 / 125 kHz: four channels at 5.1 chirps
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../sf6_channel_scan_validation/" class="md-nav__link">
<span class="md-ellipsis">
SF6 / 125 kHz channel-count test
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../sf8_5p1_trace_validation/" class="md-nav__link">
<span class="md-ellipsis">
SF8 / 125 kHz: four-channel comparison at 5.1 chirps
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../spiffs_regular_file_reads/" class="md-nav__link">
<span class="md-ellipsis">
SPIFFS regular-file reads and login replay state
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../stats_binary_frames/" class="md-nav__link">
<span class="md-ellipsis">
Stats Binary Frame Structures
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../telemetry_decoder/" class="md-nav__link">
<span class="md-ellipsis">
Telemetry decoder
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../terminal_chat_cli/" class="md-nav__link">
<span class="md-ellipsis">
Terminal Chat CLI
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../usb_serial_backpressure/" class="md-nav__link">
<span class="md-ellipsis">
Native USB backpressure and radio liveness
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../v4_pixel5_font_trial/" class="md-nav__link">
<span class="md-ellipsis">
Small-screen message fonts
</span>
</a>
</li>
<li class="md-nav__item md-nav__item--nested">
<input class="md-nav__toggle md-toggle " type="checkbox" id="__nav_88" >
<label class="md-nav__link" for="__nav_88" id="__nav_88_label" tabindex="0">
<span class="md-ellipsis">
Releases
</span>
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" data-md-level="1" aria-labelledby="__nav_88_label" aria-expanded="false">
<label class="md-nav__title" for="__nav_88">
<span class="md-nav__icon md-icon"></span>
Releases
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="../releases/1.17.1.5-doc-audit/" class="md-nav__link">
<span class="md-ellipsis">
Markdown audit — 1.17.1.5 USA Cascade
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../releases/1.17.1.5/" class="md-nav__link">
<span class="md-ellipsis">
MeshCore 1.17.1.5 Dev - USA Cascade
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../releases/1.17.1.6/" class="md-nav__link">
<span class="md-ellipsis">
MeshCore 1.17.1.6 Dev - USA Cascade
</span>
</a>
</li>
</ul>
</nav>
</li>
</ul>
</nav>
</div>
</div>
</div>
<div class="md-sidebar md-sidebar--secondary" data-md-component="sidebar" data-md-type="toc" >
<div class="md-sidebar__scrollwrap">
<div class="md-sidebar__inner">
<nav class="md-nav md-nav--secondary" aria-label="Table of contents">
<label class="md-nav__title" for="__toc">
<span class="md-nav__icon md-icon"></span>
Table of contents
</label>
<ul class="md-nav__list" data-md-component="toc" data-md-scrollfix>
<li class="md-nav__item">
<a href="#build-enforcement" class="md-nav__link">
<span class="md-ellipsis">
Build enforcement
</span>
</a>
</li>
<li class="md-nav__item">
<a href="#boot-versus-running-memory" class="md-nav__link">
<span class="md-ellipsis">
Boot versus running memory
</span>
</a>
</li>
</ul>
</nav>
</div>
</div>
</div>
<div class="md-content" data-md-component="content">
<article class="md-content__inner md-typeset">
<a href="https://github.com/mikecarper/MeshCore/edit/keymindCascade/docs/esp32_memory_budget.md" title="Edit this page" class="md-content__button md-icon" rel="edit">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M10 20H6V4h7v5h5v3.1l2-2V8l-6-6H6c-1.1 0-2 .9-2 2v16c0 1.1.9 2 2 2h4zm10.2-7c.1 0 .3.1.4.2l1.3 1.3c.2.2.2.6 0 .8l-1 1-2.1-2.1 1-1c.1-.1.2-.2.4-.2m0 3.9L14.1 23H12v-2.1l6.1-6.1z"/></svg>
</a>
<h1 id="classic-esp32-image-memory-budget">Classic ESP32 image memory budget</h1>
<p>Classic ESP32 has 320 KiB of internal DRAM, but at most 160 KiB can hold
statically allocated data. The remaining DRAM is available only through the
runtime heap. Bluetooth, tracing, and SDK reservations further constrain the
usable region. See Espressif's <a href="https://docs.espressif.com/projects/esp-idf/en/stable/esp32/api-guides/memory-types.html#dram-data-ram">memory types documentation</a>.</p>
<p>An image can therefore approach its static limit while PlatformIO reports
less than 40% of the 320 KiB total in use. PSRAM does not expand the region used
by ordinary internal <code>.data</code> and <code>.bss</code> allocations.</p>
<h2 id="build-enforcement">Build enforcement</h2>
<p>Every classic ESP32 environment inheriting <code>esp32_base</code> runs
<code>scripts/check_esp32_dram.py</code>. The release builder also adds the script when
an ESP32 profile replaces the inherited extra scripts. The check runs before
image generation, merging, and uploading, including cached <code>nobuild</code> uploads.
It requires the ELF and linker map to be present for those cached operations.
The check script must load after <code>merge-bin.py</code> so the merge target retains its
pre-action. A merge also requires the bootloader/partition flash layout;
<code>nobuild</code> cannot create a bootable merged image when that layout is absent.</p>
<p>The check reads <code>dram0_0_seg</code> from the final linker map. SDK reservations are
already reflected in that region; Bluetooth's reservation is not subtracted
a second time. The occupied span runs from the region origin to <code>_heap_start</code>,
including <code>.data</code>, <code>.bss</code>, <code>.noinit</code>, and alignment gaps. The allowed region is
the smaller of the linker's region and 160 KiB.</p>
<p>Builds must leave at least <strong>8 KiB free within that static region</strong>. This is
an additional project margin against near-full images, not an Espressif
hardware limit or a prediction of free heap. A profile may require a larger
margin with <code>custom_esp32_static_dram_reserve</code> in bytes; values below 8192 are
rejected. Missing or unrecognized map boundaries also fail the check.</p>
<p>For the Heltec V2 build used to investigate the repeater report:</p>
<table>
<thead>
<tr>
<th>Shared repeater defaults</th>
<th style="text-align: right;">Static span</th>
<th style="text-align: right;">Static region</th>
<th style="text-align: right;">Remaining</th>
<th>Result</th>
</tr>
</thead>
<tbody>
<tr>
<td>Previous 255 scope slots</td>
<td style="text-align: right;">124,020 B</td>
<td style="text-align: right;">124,580 B</td>
<td style="text-align: right;">560 B</td>
<td>Rejected</td>
</tr>
<tr>
<td>Tuned 31 scope slots</td>
<td style="text-align: right;">108,308 B</td>
<td style="text-align: right;">124,580 B</td>
<td style="text-align: right;">16,272 B</td>
<td>Passed</td>
</tr>
</tbody>
</table>
<p>These measurements remove the board's existing scope-capacity override to
exercise the shared defaults. The normal Heltec V2 profile already used 31
scope slots. Exact sizes vary with build flags and SDK versions.</p>
<p>To inspect an existing classic ESP32 build:</p>
<pre><code class="language-sh">python3 scripts/check_esp32_dram.py .pio/build/Heltec_v2_repeater/firmware.map
python3 test/test_esp32_dram.py
</code></pre>
<p>ESP32-S2, S3, and C-series chips have different memory maps and do not inherit
this classic ESP32 check.</p>
<h2 id="boot-versus-running-memory">Boot versus running memory</h2>
<p>The build gate checks static placement needed to load and start the image.
It never counts heap-only RAM toward that static budget. Allocations made with
<code>new</code> or <code>malloc</code> in global constructors consume heap and are not included in
the static span. Moving a table there changes its placement, not total RAM
consumption.</p>
<p>Successful build checks do not prove that every runtime configuration will
boot. Hardware validation must still cover startup allocations and the enabled
Wi-Fi/Bluetooth services, recording minimum free internal heap and the largest
free internal block. Available heap changes during initialization; for example,
the Arduino 2.x repeater releases unused Bluetooth controller RAM in
<code>initArduino()</code>, after global constructors have run.</p>
</article>
</div>
<script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script>
</div>
</main>
<footer class="md-footer">
<div class="md-footer-meta md-typeset">
<div class="md-footer-meta__inner md-grid">
<div class="md-copyright">
Made with
<a href="https://squidfunk.github.io/mkdocs-material/" target="_blank" rel="noopener">
Material for MkDocs
</a>
</div>
</div>
</div>
</footer>
</div>
<div class="md-dialog" data-md-component="dialog">
<div class="md-dialog__inner md-typeset"></div>
</div>
<script id="__config" type="application/json">{"annotate": null, "base": "..", "features": ["content.action.edit", "content.code.copy", "search.highlight", "search.suggest"], "search": "../assets/javascripts/workers/search.2c215733.min.js", "tags": null, "translations": {"clipboard.copied": "Copied to clipboard", "clipboard.copy": "Copy to clipboard", "search.result.more.one": "1 more on this page", "search.result.more.other": "# more on this page", "search.result.none": "No matching documents", "search.result.one": "1 matching document", "search.result.other": "# matching documents", "search.result.placeholder": "Type to start searching", "search.result.term.missing": "Missing", "select.version": "Select version"}, "version": null}</script>
<script src="../assets/javascripts/bundle.d7400e89.min.js"></script>
<script src="../_javascript/firmware_picker.js"></script>
<script src="../_javascript/telemetry_decoder.js"></script>
<script src="../_javascript/filter_tool.js"></script>
</body>
</html>