MeshCore Platforms

COMPARING · CHOOSING · WHAT THE CHIP DECIDES

MeshCore runs on four platform families. The same source code, the same protocol, the same radio — and yet one node can do things another cannot. This chapter shows why the platform matters, how the four compare, what you can buy today and how to choose. What each family puts in the chip is covered in The Four Platform Families.

[!NOTE] Source. This page has been verified against the firmware itself: MeshCore v1.16.0 (FIRMWARE_BUILD_DATE "6 Jun 2026"), commit 03b6ef4, 28 July 2026 — platformio.ini, variants/*/platformio.ini (79 directories, 507 build targets), boards/*.json (41 definitions), examples/companion_radio/main.cpp, src/helpers/IdentityStore.h and src/Utils.cpp. Every count in this chapter was also checked against commit a3a1aa5 (19 July 2026) and is identical there. To reproduce: tools/platform-overview.py.

Why the platform matters

Take the sharpest example: a companion that talks to your phone over Bluetooth. It exists as a build target on ESP32 and on nRF52840, and on neither of the other two families. Not because the hardware cannot do it — the Raspberry Pi Pico W has Bluetooth on board — but because the firmware has no implementation for it. In examples/companion_radio/main.cpp lines 55-66 the WiFi and BLE branches for RP2040 are commented out, and every RP2040 variant sets lib_ignore = BLE.

Same protocol, same radio, different behaviour. The platform decides which transports, storage, displays and update methods are available.

Note the wording. The firmware does not speak of microcontrollers but of platforms: the four build targets are named ESP32_PLATFORM, NRF52_PLATFORM, RP2040_PLATFORM and STM32_PLATFORM (platformio.ini lines 63, 90, 104, 113). And three of the four are strictly speaking not a microcontroller but a SoC: a chip with the radio inside it. Only the RP2040 is a bare microcontroller.

So "MeshCore supports four microcontrollers" is a double simplification. There are four platform bases in platformio.ini, covering at least seven different SoCs and two processor architectures.

What exactly distinguishes a SoC from an MCU — and why every SoC contains an MCU but not the other way round — is covered in The Hardware of a Node.

The four families at a glance

Family	SoCs	Core	Clock	RAM	Flash for the app	Radio	Variants	Build targets
ESP32	ESP32, S3, C3, C6	Xtensa LX6/LX7 + RISC-V	160–240 MHz	320 KB, up to 8 MB with PSRAM	4–16 MB	external, over SPI	37	270
nRF52	nRF52840	Cortex-M4F	64 MHz	230 KB	792–796 KB	external, over SPI	34	199
RP2040	RP2040	2× Cortex-M0+	133 MHz *	264 KB *	2 MB *	external, over SPI	4	22
STM32WL	STM32WLE5CCU	Cortex-M4	48 MHz	64 KB	224 KB	on the die (SubGHz)	4	16

[!NOTE] * These three RP2040 figures are not in the MeshCore repo. The four RP2040 boards use PlatformIO's built-in board definitions; there is no boards/*.json for them. The source for clock speed, RAM and flash is the RP2040 Datasheet by Raspberry Pi Ltd. Every other figure in this table comes from boards/*.json and variants/*/platformio.ini in the firmware repo.

What each family actually brings — the SoCs under the heading, the cores, the power management and what the chip demands in memory and energy — is worked out family by family in The Four Platform Families.

Comparison on six axes

Axis	ESP32	nRF52840	RP2040	STM32WL
Compute	highest, 160–240 MHz, S3 with vector instructions	64 MHz with FPU	133 MHz, two cores, no FPU	48 MHz, the lowest
Memory	generous; PSRAM possible	ample for every role	ample for every role	tight: 64 KB RAM, 224 KB app flash
Connectivity	BLE, WiFi, ESP-NOW, USB	BLE and USB	USB only	USB only
Storage	SPIFFS on internal flash	InternalFS plus EXTRAFS	LittleFS	LittleFS port in arch/stm32/
Power	highest; no power management in the firmware	lowest; the only one actively supported, but on 5 of 19 boards	no power management in the firmware	frugal by nature; no power management in the firmware
Ease of flashing	web flasher over USB	drag a .uf2, or OTA over Bluetooth	drag a .uf2	.hex with ST-Link or DFU

[!NOTE] No current figures. This chapter contains no numbers in mA. They do not appear anywhere in the firmware repo, and datasheet figures say little about a node with a radio, display and GPS attached. For the one platform where the firmware really does something about it, docs/nrf52_power_management.md is the place to look.

Which roles run on which platform

A hard count of the [env:] blocks in variants/*/platformio.ini. Each number is a count of build targets, not of boards — one board usually yields five to ten targets.

Role	ESP32	nRF52	RP2040	STM32WL
companion BLE	38	40	0	0
companion WiFi	17	0	0	0
companion USB	33	35	4	4
companion serial	3	0	0	0
repeater	83	42	6	5
room server	34	35	4	0
sensor	9	6	0	3
KISS modem	36	36	4	4
terminal chat	17	5	4	0
total	270	199	22	16

Two gaps stand out. STM32WL has no room server at all, and RP2040 has no sensor build. That is not a limitation of the chip but a choice in the variants: nobody has created them.

Of the 270 ESP32 targets, sixteen come from the three C6 variants: five repeater, five companion BLE, three KISS modem, two room server and one companion USB.

What you can buy and flash today

The firmware builds for four families. The web flasher — the route most people take — offers two. The saved page of 27 July 2026 lists sixty devices:

Family	Devices in the flasher	Share	Variants in the repo
ESP32	32	53 %	37
nRF52840	27	45 %	34
RP2040	1, and not flashable through the web flasher	2 %	4
STM32WL	0	0 %	4

The single RP2040 device in the list, the Pico with a WaveShare SX1262 module, gets no platform icon but a generic glyph. The flasher's own configuration gives the reason: "type": "noflash". You get a link to the .uf2 file and copy it across yourself.

For STM32WL there is nothing at all. Anyone who wants such a node compiles it themselves and flashes it with ST-Link or DFU. Within MeshCore, STM32WL is not a consumer platform but a builder's platform.

Within ESP32 the S3 dominates: 27 of the 32 devices. Alongside it four with the classic ESP32 (Heltec v2, LilyGo LoRa32 V2.1_1.6 and the two T-Beams) and one with a C3 (Seeed Xiao C3). Of the C6, the sub-SoC carrying the "experimental" label, not a single device appears in the list.

[!NOTE] The flasher list is not a copy of variants/. Seven ESP32-S3 devices in the list — the LilyGo T-Deck Max, T-Deck Pro, T-Display Pro, T-Lora Pager, T-Watch S3 Plus, T-Watch Ultra and T5 E-Paper S3 Pro — have no variant in this repo. They run the closed-source Ripple GUI or MeshOS firmware. Conversely, the four STM32WL variants, three of the four RP2040 variants, all three C6 variants and generic targets such as generic-e22 and meshtiny do not appear in the flasher.

How MeshCore absorbs the differences

One API, four cores

framework = arduino appears exactly once in the entire repo: platformio.ini line 17, in [arduino_base]. All four platform bases extend it, and none of the 79 variants overrides it.

Even so, these are four different Arduino cores: Arduino-ESP32 on ESP-IDF, the Adafruit nRF52 core on the SoftDevice, the earlephilhower arduino-pico, and STM32duino on the STM32 HAL. The same API, four implementations — hence the #ifdef chains throughout the helper layer.

How sharp that can get is visible in examples/companion_radio/main.cpp lines 5-6. There sits a hand-written _atoi() with a note that the standard C function is broken on some platforms.

A tidy example of the opposite movement is src/helpers/IdentityStore.h lines 3-11, where one macro covers four cases:

#if defined(ESP32) || defined(RP2040_PLATFORM)
  #define FILESYSTEM  fs::FS
#elif defined(NRF52_PLATFORM) || defined(STM32_PLATFORM)
  #define FILESYSTEM  Adafruit_LittleFS
#endif

Everything above that line — storing identities, keeping contacts — no longer needs to know which platform it is running on.

The core is not Arduino-dependent

The Arduino dependency lives in src/helpers/ and examples/, not in the protocol core. In src/Utils.cpp lines 5-7 the #include <Arduino.h> sits behind #ifdef ARDUINO, and src/MeshCore.h lines 25 and 34 use ARDUINO only to switch debug output on or off.

The proof is at the bottom of platformio.ini: [env:native] (lines 158-168) builds against googletest, with platform = native, mocks from test/mocks/ and not a single line of Arduino. That is why a Zephyr port of MeshCore can exist that speaks exactly the same protocol.

Four flash artefacts

Platform	Build script	Result	How it reaches the node
ESP32	merge-bin.py	a single .bin	esptool or the web flasher
nRF52	create-uf2.py	.uf2	drag onto the USB drive, or OTA over Bluetooth
RP2040	upload_protocol = picotool	.uf2	drag onto the UF2 bootloader
STM32	arch/stm32/build_hex.py	.hex via objcopy -O ihex	ST-Link or DFU

That is also the explanation for the flasher table above. Only ESP32 and nRF52 have an artefact a web page can write straight to the device.

Choosing

In words:

• Need to pair with a phone? Then ESP32 or nRF52840; the other two have no BLE companion.
• Running on a battery or solar panel? nRF52840 — but first check whether your board is marked "Implemented" in the table in docs/nrf52_power_management.md.
• Need WiFi, OTA or ESP-NOW? ESP32 only.
• A small, frugal repeater without a phone, and you build it yourself? STM32WL. Count on 64 KB of RAM and on flashing with ST-Link or DFU.
• RP2040 is the choice for someone who already has a Pico lying around and wants a repeater or USB companion. No BLE, no WiFi, no display.

Which specific board fits is covered in Hardware Overview.

Sources

Firmware: meshcore-dev/MeshCore, branch main, commit 03b6ef4, 28 July 2026, v1.16.0.

• platformio.ini — lines 16-53 [arduino_base] with framework = arduino on line 17; 67-70 [esp32_ota]; 158-168 [env:native]
• variants/ — 79 directories holding 507 [env:] blocks between them
• boards/ — 41 board definitions with mcu, f_cpu, maximum_ram_size and maximum_size
• examples/companion_radio/main.cpp — lines 5-6 the hand-written _atoi()
• src/helpers/IdentityStore.h — lines 3-11, the FILESYSTEM abstraction
• src/Utils.cpp — lines 5-7, #ifdef ARDUINO
• merge-bin.py, create-uf2.py and arch/stm32/build_hex.py — the three build scripts that produce the flash artefacts

Device list: saved page of the MeshCore web flasher, 27 July 2026, sixty devices.

Not from the firmware repo:

• RP2040 Datasheet, Raspberry Pi Ltd — clock speed, SRAM and flash of the RP2040

To recompute: tools/platform-overview.py generates tables 1, 3 and 4 from a clone of the firmware repo and a saved flasher page.

Translated from Dutch by Anthropic Claude