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{{Short description|Family of Wi-Fi and Bluetooth microcontrollers from Espressif}}
{{Infobox product
| name = ESP32
| developer = Espressif Systems
| type = Microcontroller family (system on a chip) with Wi-Fi and Bluetooth
| release_date = September 6, 2016 (original ESP32)
| cpu = Xtensa LX6 (ESP32); Xtensa LX7 (ESP32-S2, ESP32-S3); RISC-V (later series)
| memory = 520 KB SRAM (ESP32); 512 KB SRAM (ESP32-S3)
| connectivity = 2.4 GHz Wi-Fi, Bluetooth; full-speed USB on the S2 and S3
| predecessor = ESP8266
| website = [https://www.espressif.com espressif.com]
}}
The '''ESP32''' is a family of low-cost microcontrollers from Espressif Systems of Shanghai that combine one or two processor cores, memory, a Wi-Fi radio and a Bluetooth radio on one chip. The ESP32-S3 sits in both devices that [[Molecular Reality Corporation]] has called the [[MR1]], the [[MR1 Molecular Streaming Device]] and the [[MR1 Nanopore Reader]], where it receives the digitized current of a [[nanopore]], sends it out over USB and serves a thinned-out copy of the trace over Wi-Fi to an oscilloscope in a web page.

== Family ==
Espressif presented the first ESP32 at a press conference in Shanghai on September 6, 2016, as the successor of the ESP8266.<ref name="launch">{{cite press release |title=Espressif announces the launch of ESP32 Cloud on Chip and funding by Fosun Group |publisher=Espressif Systems |date=2016-09-07 |url=https://www.espressif.com/en/media_overview/news/20160907-esp32briefing}}</ref> It has one or two Xtensa LX6 cores at up to 240 MHz, 520 KB of on-chip SRAM, and Bluetooth 4.2.<ref name="ds5">{{cite web |url=https://documentation.espressif.com/esp32_datasheet_en.pdf |title=ESP32 series datasheet, version 5.3 |publisher=Espressif Systems |access-date=October 25, 2026}}</ref> The family has since grown to series with Xtensa cores, among them the single-core S2 and the dual-core S3, and series with RISC-V cores, among them the single-core C series, mostly at 160 MHz, and the dual-core P4 at 400 MHz.<ref name="socs">{{cite web |url=https://www.espressif.com/en/products/socs |title=SoCs |publisher=Espressif Systems |access-date=October 25, 2026}}</ref>

The ESP32-S3 has two Xtensa LX7 cores at up to 240 MHz, 512 KB of SRAM, 2.4 GHz Wi-Fi (802.11 b/g/n), Bluetooth 5 (LE), 45 programmable pins and a full-speed USB controller, which runs at 12 Mbit/s.<ref name="ds2">{{cite web |url=https://documentation.espressif.com/esp32-s3_datasheet_en.pdf |title=ESP32-S3 series datasheet, version 2.2 |publisher=Espressif Systems |access-date=October 25, 2026}}</ref> Its instruction set has extensions with 128-bit registers and vector operations for "specific AI and DSP (Digital Signal Processing) algorithms". Two 12-bit successive-approximation converters serve up to 20 analog pins, with a note in the datasheet that the channels of the second converter cannot be used while Wi-Fi is on. The measurement of the pore current does not use them.

== In the MR1 devices ==
[[File:ESP32_S3_roles_in_the_MR1_reader.svg|thumb|right|upright=1.5|alt=Block diagram: pore, amplifier and converter feed the ESP32-S3, whose first core sends frames over USB and whose second core handles Wi-Fi, an oscilloscope page and a serial link to the pump module|Data paths of the reader board in the open MR1 Nanopore Reader design, with the work of the two cores of the ESP32-S3. The design has not been built.]]
The older MR1, the handheld, pairs the S3 with an LMP7721 amplifier, a MAX11169 converter of 16 bits and an MCP4822 converter that sets the voltage across the pore.<ref name="records">{{cite web |title=Company records |publisher=Molecular Reality Corporation |date=October 2026}}</ref> The open design of the reader splits the work between the two cores. Core 1 runs a loop that samples an external converter of 16 or 18 bits 100,000 times a second by direct memory access and sends the samples out over USB. Core 0 runs Wi-Fi, a web server, the oscilloscope, which receives the trace decimated to 1,000 points a second, and the serial link to the pump module, which has its own microcontroller, an STM32G431.<ref name="github">{{cite web |url=https://github.com/EpicQuestBio/MR1 |title=MR1 Nanopore Reader |website=GitHub |date=October 16, 2026}}</ref>

A stream of 146-byte frames of 64 samples each, at 1,562.5 frames a second, is about 1.83 Mbit/s and fits within full-speed USB. The README of the repository nevertheless calls the interface "native high-speed USB CDC", and the data-acquisition specification lists both 12 Mbit/s and 480 Mbit/s, the latter being a speed the chip does not have.<ref name="github" /> The module on the board differed between files. The schematic and the firmware headers named an ESP32-S3-MINI-1U, whose part number ending in N8 means 8 MB of flash and no extra RAM, while the bill of materials listed an ESP32-S3-WROOM-1-N16R8, with 16 MB of flash and 8 MB of PSRAM. A commit of October 21, 2026 replaced the second with the first.<ref name="mini">{{cite web |url=https://documentation.espressif.com/esp32-s3-mini-1_mini-1u_datasheet_en.pdf |title=ESP32-S3-MINI-1 and ESP32-S3-MINI-1U datasheet, version 1.7 |publisher=Espressif Systems |access-date=October 25, 2026}}</ref><ref name="commit">{{cite commit |repo=EpicQuestBio/MR1 |hash=0aa08a9 |date=2026-10-21 |message=fix: Reconcile MR1 board stackup, BOM, interposer, and pore guidelines}}</ref>

A second bench of the company in San Mateo, California, streams from a rig built around an ESP32.<ref name="records" />

== Frozen inference ==
The first version of the company's essay on a nanopore world model proposed learning on the devices. The second lists "Federated on ESP32" among its corrections and says that the ESP32 in the company's devices "cannot backprop a ViT or Mamba", so it should run a frozen model while the fleet of devices, with the [[World Particle Project]], supplies the training data.<ref name="wm">{{cite web |url=https://molecularreality.com/nanopore-world-model |title=Keltar's Critique v2: The Nanopore World Model (Hardened) |publisher=Molecular Reality Corporation |date=June 2026}}</ref> The memory explains the verdict. A model of 5 million parameters at one byte each takes 5 MB, ten times the 512 KB of SRAM on the S3, before any activations or gradients are stored.

== Maxine's line ==
The instructions of the company's character [[Maxine (character)|Maxine]] contain a line about the board: "Keltar talks about star-dust; I just need to figure out how to mitigate parasitic capacitance on this ESP32 board!"<ref name="maxine">{{cite web |title=Company records |publisher=Molecular Reality Corporation |date=2026-02}}</ref> Capacitance at the input of the amplifier turns its voltage noise into current noise that grows with frequency, as described under [[Nanopore noise]]. In the reader the amplifier is a small board under the cartridge, apart from the board that carries the microcontroller and its radio.

== See also ==
* [[Transimpedance amplifier]]
* [[Analog front end]]
* [[Analog-to-digital converter]]
* [[Keltar]]

== References ==
{{Reflist}}

{{MR1}}

[[Category:Microcontrollers]]
[[Category:Espressif Systems]]
[[Category:Wireless networking]]