Internal SPI Flash & Optional Quad/Octal PSRAM
QSPI
Chip Pad: GPIO29
Quad MSPI on GPIO26–32; -R8 Octal PSRAM additionally uses GPIO33–37 (Pins 28–30)
Leave Pins 28–30 unconnected on -R8 modules.
Built around the dual-core 240 MHz ESP32-S3 SoC, 40 MHz crystal, 4/8/16 MB Quad SPI flash, and optional 2 MB Quad (-R2) or 8 MB Octal (-R8) PSRAM, ESP32-S3-WROOM-1 (18.0×25.5 mm PCB antenna) and ESP32-S3-WROOM-1U (18.0×19.2 mm U.FL) expose 36 bidirectional 3.3 V GPIOs on a 40+1 pad 1.27 mm footprint. On 8 MB Octal PSRAM (-N8R8 / -N16R8) modules, Pins 28–30 (IO35, IO36, IO37) are occupied internally by the Octal MSPI bus leaving 33 free GPIOs.
Onboard Peripherals & Internal Signals
External Coaxial Antenna Receptacle (U.FL / IPEX MHF I)
System
Chip Pad: LNA_IN
Onboard 50Ω U.FL / IPEX external 2.4 GHz antenna connector
Connect an external 50Ω 2.4 GHz antenna before transmitting.
Pin Assignment Planner
Add the peripherals you need and plan the pin assignments
Full Pin Reference (41 Pins)
| Pin # | Label | Type | Functions | Warnings & Notes |
|---|---|---|---|---|
| 1 | GND | ground | GND |
Module system ground (0V)
|
| 2 | 3V3 | power | 3V3 |
[CAUTION] 3.0V–3.6V supply only (>=500 mA current capability + 10 µF & 0.1 µF decoupling)
Wi-Fi TX bursts draw high peak current. Exceeding 3.6V permanently damages the SoC and onboard flash.
Main 3.3V module power supply input (3.0V–3.6V; >=500 mA regulator recommended)
|
| 3 | EN CHIP_PU | reset | CHIP_PU |
[CAUTION] Active-HIGH chip enable / reset — never leave floating
Add an external 10 kΩ pull-up to 3.3V and 1 µF delay capacitor to GND.
Active-HIGH chip enable / reset input (EN / CHIP_PU)
|
| 4 | IO4 GPIO4 | mixed | GPIO4 ADC1_CH3 TOUCH4 |
General-purpose 3.3V GPIO4 (NOT 5V tolerant)
|
| 5 | IO5 GPIO5 | mixed | GPIO5 ADC1_CH4 TOUCH5 |
General-purpose 3.3V GPIO5 (NOT 5V tolerant)
|
| 6 | IO6 GPIO6 | mixed | GPIO6 ADC1_CH5 TOUCH6 |
General-purpose 3.3V GPIO6 (NOT 5V tolerant)
|
| 7 | IO7 GPIO7 | mixed | GPIO7 ADC1_CH6 TOUCH7 |
General-purpose 3.3V GPIO7 (NOT 5V tolerant)
|
| 8 | IO15 GPIO15 | mixed | GPIO15 ADC2_CH4 XTAL_32K_P |
[CAUTION] ADC2 channel unavailable while Wi-Fi / BLE radio uses SAR ADC2 arbiter
Prefer ADC1 (GPIO1–GPIO10) for reliable analog measurements during wireless operation.
General-purpose 3.3V GPIO15 (NOT 5V tolerant)
|
| 9 | IO16 GPIO16 | mixed | GPIO16 ADC2_CH5 XTAL_32K_N |
[CAUTION] ADC2 channel unavailable while Wi-Fi / BLE radio uses SAR ADC2 arbiter
Prefer ADC1 (GPIO1–GPIO10) for reliable analog measurements during wireless operation.
General-purpose 3.3V GPIO16 (NOT 5V tolerant)
|
| 10 | IO17 GPIO17 | mixed | GPIO17 ADC2_CH6 U1TXD |
[CAUTION] ADC2 channel unavailable while Wi-Fi / BLE radio uses SAR ADC2 arbiter
Prefer ADC1 (GPIO1–GPIO10) for reliable analog measurements during wireless operation.
General-purpose 3.3V GPIO17 (NOT 5V tolerant)
|
| 11 | IO18 GPIO18 | mixed | GPIO18 ADC2_CH7 U1RXD |
[CAUTION] ADC2 channel unavailable while Wi-Fi / BLE radio uses SAR ADC2 arbiter
Prefer ADC1 (GPIO1–GPIO10) for reliable analog measurements during wireless operation.
General-purpose 3.3V GPIO18 (NOT 5V tolerant)
|
| 12 | IO8 GPIO8 | mixed | GPIO8 ADC1_CH7 TOUCH8 |
General-purpose 3.3V GPIO8 (NOT 5V tolerant)
|
| 13 | IO19 GPIO19 | mixed | GPIO19 ADC2_CH8 USB_D- |
[CAUTION] ADC2 channel unavailable while Wi-Fi / BLE radio uses SAR ADC2 arbiter
Prefer ADC1 (GPIO1–GPIO10) for reliable analog measurements during wireless operation.
[INFO] Native Full-Speed USB OTG & USB Serial/JTAG differential pair (D- / D+)
Reconfiguring GPIO19/GPIO20 as GPIO disconnects native USB CDC/JTAG/DFU.
General-purpose 3.3V GPIO19 (NOT 5V tolerant)
|
| 14 | IO20 GPIO20 | mixed | GPIO20 ADC2_CH9 USB_D+ |
[CAUTION] ADC2 channel unavailable while Wi-Fi / BLE radio uses SAR ADC2 arbiter
Prefer ADC1 (GPIO1–GPIO10) for reliable analog measurements during wireless operation.
[INFO] Native Full-Speed USB OTG & USB Serial/JTAG differential pair (D- / D+)
Reconfiguring GPIO19/GPIO20 as GPIO disconnects native USB CDC/JTAG/DFU.
General-purpose 3.3V GPIO20 (NOT 5V tolerant)
|
| 15 | IO3 GPIO3 | mixed | GPIO3 ADC1_CH2 TOUCH3 |
[INFO] JTAG signal source strapping pin (floating at reset unless eFuse-configured)
Sampled at reset to select USB Serial/JTAG vs pad JTAG (GPIO39–42) when eFuse JTAG_SEL_ENABLE is set.
General-purpose 3.3V GPIO3 (NOT 5V tolerant)
|
| 16 | IO46 GPIO46 | digital | GPIO46 |
[CAUTION] Boot mode & ROM log strapping pin (weak pull-down; bidirectional I/O on ESP32-S3)
Keep LOW or floating at reset for normal SPI boot or Joint Download Boot. Unlike ESP32-S2, GPIO46 IS a full bidirectional GPIO on ESP32-S3.
General-purpose 3.3V GPIO46 (NOT 5V tolerant)
|
| 17 | IO9 GPIO9 | mixed | GPIO9 ADC1_CH8 TOUCH9 |
General-purpose 3.3V GPIO9 (NOT 5V tolerant)
|
| 18 | IO10 GPIO10 | mixed | GPIO10 ADC1_CH9 TOUCH10 FSPICS0 |
General-purpose 3.3V GPIO10 (NOT 5V tolerant)
|
| 19 | IO11 GPIO11 | mixed | GPIO11 ADC2_CH0 TOUCH11 FSPID |
[CAUTION] ADC2 channel unavailable while Wi-Fi / BLE radio uses SAR ADC2 arbiter
Prefer ADC1 (GPIO1–GPIO10) for reliable analog measurements during wireless operation.
General-purpose 3.3V GPIO11 (NOT 5V tolerant)
|
| 20 | IO12 GPIO12 | mixed | GPIO12 ADC2_CH1 TOUCH12 FSPICLK |
[CAUTION] ADC2 channel unavailable while Wi-Fi / BLE radio uses SAR ADC2 arbiter
Prefer ADC1 (GPIO1–GPIO10) for reliable analog measurements during wireless operation.
General-purpose 3.3V GPIO12 (NOT 5V tolerant)
|
| 21 | IO13 GPIO13 | mixed | GPIO13 ADC2_CH2 TOUCH13 FSPIQ |
[CAUTION] ADC2 channel unavailable while Wi-Fi / BLE radio uses SAR ADC2 arbiter
Prefer ADC1 (GPIO1–GPIO10) for reliable analog measurements during wireless operation.
General-purpose 3.3V GPIO13 (NOT 5V tolerant)
|
| 22 | IO14 GPIO14 | mixed | GPIO14 ADC2_CH3 TOUCH14 |
[CAUTION] ADC2 channel unavailable while Wi-Fi / BLE radio uses SAR ADC2 arbiter
Prefer ADC1 (GPIO1–GPIO10) for reliable analog measurements during wireless operation.
General-purpose 3.3V GPIO14 (NOT 5V tolerant)
|
| 23 | IO21 GPIO21 | digital | GPIO21 |
General-purpose 3.3V GPIO21 (NOT 5V tolerant)
|
| 24 | IO47 GPIO47 | digital | GPIO47 |
General-purpose 3.3V GPIO47 (NOT 5V tolerant)
|
| 25 | IO48 GPIO48 | digital | GPIO48 |
General-purpose 3.3V GPIO48 (NOT 5V tolerant)
|
| 26 | IO45 GPIO45 | digital | GPIO45 |
[DANGER] VDD_SPI flash voltage strap (weak pull-down: LOW=3.3V, HIGH=1.8V)
Pulling GPIO45 HIGH at reset switches VDD_SPI to 1.8V, causing boot failure on 3.3V flash/PSRAM parts.
General-purpose 3.3V GPIO45 (NOT 5V tolerant)
|
| 27 | IO0 GPIO0 | digital | GPIO0 |
[CAUTION] Boot mode strapping pin (weak pull-up: HIGH=SPI Boot, LOW=Download Boot)
Pulling GPIO0 LOW with GPIO46 LOW at reset enters Joint Download Boot (USB Serial/JTAG + USB OTG DFU + UART0).
General-purpose 3.3V GPIO0 (NOT 5V tolerant)
|
| 28 | IO35 GPIO35 | digital | GPIO35 SPIIO6 |
[CAUTION] Octal MSPI bus (SPIIO4–SPIIO7 / SPIDQS) — occupied on -R8 Octal PSRAM or Octal Flash variants!
Freely usable on Quad flash / Quad PSRAM (-N4, -N8, -N16, -R2) parts, but internally occupied on 8 MB Octal PSRAM (-R8 / N8R8 / N16R8) or Octal Flash parts.
[CAUTION] Occupied by internal Octal PSRAM on -N8R8 / -N16R8 modules — DO NOT use on -R8!
Usable as GPIO on Quad flash/PSRAM (-N4, -N8, -N16, -N4R2, -N8R2) modules, but wired internally to 8 MB Octal SPI PSRAM on -N8R8 and -N16R8 modules.
General-purpose 3.3V GPIO35 (NOT 5V tolerant)
|
| 29 | IO36 GPIO36 | digital | GPIO36 SPIIO7 |
[CAUTION] Octal MSPI bus (SPIIO4–SPIIO7 / SPIDQS) — occupied on -R8 Octal PSRAM or Octal Flash variants!
Freely usable on Quad flash / Quad PSRAM (-N4, -N8, -N16, -R2) parts, but internally occupied on 8 MB Octal PSRAM (-R8 / N8R8 / N16R8) or Octal Flash parts.
[CAUTION] Occupied by internal Octal PSRAM on -N8R8 / -N16R8 modules — DO NOT use on -R8!
Usable as GPIO on Quad flash/PSRAM (-N4, -N8, -N16, -N4R2, -N8R2) modules, but wired internally to 8 MB Octal SPI PSRAM on -N8R8 and -N16R8 modules.
General-purpose 3.3V GPIO36 (NOT 5V tolerant)
|
| 30 | IO37 GPIO37 | digital | GPIO37 SPIDQS |
[CAUTION] Octal MSPI bus (SPIIO4–SPIIO7 / SPIDQS) — occupied on -R8 Octal PSRAM or Octal Flash variants!
Freely usable on Quad flash / Quad PSRAM (-N4, -N8, -N16, -R2) parts, but internally occupied on 8 MB Octal PSRAM (-R8 / N8R8 / N16R8) or Octal Flash parts.
[CAUTION] Occupied by internal Octal PSRAM on -N8R8 / -N16R8 modules — DO NOT use on -R8!
Usable as GPIO on Quad flash/PSRAM (-N4, -N8, -N16, -N4R2, -N8R2) modules, but wired internally to 8 MB Octal SPI PSRAM on -N8R8 and -N16R8 modules.
General-purpose 3.3V GPIO37 (NOT 5V tolerant)
|
| 31 | IO38 GPIO38 | digital | GPIO38 |
General-purpose 3.3V GPIO38 (NOT 5V tolerant)
|
| 32 | IO39 GPIO39 | digital | GPIO39 MTCK |
General-purpose 3.3V GPIO39 (NOT 5V tolerant)
|
| 33 | IO40 GPIO40 | digital | GPIO40 MTDO |
General-purpose 3.3V GPIO40 (NOT 5V tolerant)
|
| 34 | IO41 GPIO41 | digital | GPIO41 MTDI |
General-purpose 3.3V GPIO41 (NOT 5V tolerant)
|
| 35 | IO42 GPIO42 | digital | GPIO42 MTMS |
General-purpose 3.3V GPIO42 (NOT 5V tolerant)
|
| 36 | RXD0 GPIO44 | digital | GPIO44 U0RXD |
General-purpose 3.3V GPIO44 (NOT 5V tolerant)
|
| 37 | TXD0 GPIO43 | digital | GPIO43 U0TXD |
General-purpose 3.3V GPIO43 (NOT 5V tolerant)
|
| 38 | IO2 GPIO2 | mixed | GPIO2 ADC1_CH1 TOUCH2 |
General-purpose 3.3V GPIO2 (NOT 5V tolerant)
|
| 39 | IO1 GPIO1 | mixed | GPIO1 ADC1_CH0 TOUCH1 |
General-purpose 3.3V GPIO1 (NOT 5V tolerant)
|
| 40 | GND | ground | GND |
Module system ground (0V)
|
| 41 | EPAD | ground | GND |
Underside exposed thermal & RF ground pad (connect to host GND plane)
|