Title: Wiring Modules and Peripherals
Description: Find the pins your board uses for CC1101, NRF24, NFC, GPS, and SD cards, and wire add-on modules safely.
URL: /latest/getting-started/peripheral-wiring/
Version: latest
Section: Getting Started
Keywords: wiring, pinout, pins, GPIO, CC1101, NRF24, PN532, GPS, SD card, SPI, I2C, UART
Search index: /search-index.json

# Wiring Modules and Peripherals

> Find the pins your board uses for CC1101, NRF24, NFC, GPS, and SD cards, and wire add-on modules safely.

## On this page

- [What this does](#what-this-does)
- [Do I need this page?](#do-i-need-this-page)
- [Before you start](#before-you-start)
- [Find your board’s pins](#find-your-boards-pins)
- [SD card (changeable at runtime)](#sd-card-changeable-at-runtime)
- [CC1101 SubGHz](#cc1101-subghz)
- [Build-time pins](#build-time-pins)
- [Module wiring reference](#module-wiring-reference)
- [CC1101 (SubGHz)](#cc1101-subghz-1)
- [NRF24L01+](#nrf24l01)
- [PN532 (NFC)](#pn532-nfc)
- [GPS](#gps)
- [Verified board wiring](#verified-board-wiring)
- [Flipper Zero to ESP32](#flipper-zero-to-esp32)
- [GhostLink (two GhostESP boards)](#ghostlink-two-ghostesp-boards)
- [GhostLink P1](#ghostlink-p1)
- [Troubleshooting](#troubleshooting)
- [Related tasks](#related-tasks)

---

## What this does
This page explains how GhostESP maps add-on modules to ESP32 pins, and how to find the exact pins your board is already using.
## Do I need this page?
If you bought or already own a supported board, you probably don’t. Every release build ships with its pins already configured, so a board with a built-in CC1101, NRF24, NFC, or GPS works out of the box.
You need this page when you are:
- Adding a module to a generic ESP32 board
- Changing SD card pins
- Building a custom board configuration
## Before you start
- 3.3 V logic only. ESP32 GPIOs are not 5 V tolerant. Feeding 5 V into a pin can destroy the chip.
- Check the [Supported Hardware](/latest/getting-started/supported-hardware/) table first — many “missing feature” problems are really “this board doesn’t have that hardware.”
- Have a way to read serial output at 115200 baud. Boot logs and status commands are how you confirm wiring.
## Find your board’s pins
### SD card (changeable at runtime)
sd_config
prints the pins currently in use. To change them without rebuilding:
sd_pins_spi <cs> <clk> <miso> <mosi>
sd_save_config
sd_save_config stores the pins in NVS so they survive a reboot. This is the only peripheral most users ever need to reconfigure by hand.
### CC1101 SubGHz
Start the scanner and read the first log line:
subghz start
GhostESP prints the pins it is actually using:
SubGHz cfg: SPI2 MOSI=18 MISO=38 SCK=40 CSN=39 GDO0=41 GDO2=-1
If that line does not appear, the build was compiled without SubGHz support for your board.
### Build-time pins
If you are compiling your own build, every peripheral pin is set under Ghost ESP Options in menuconfig:
Peripheral |
menuconfig section |
CC1101 |
SubGHz Options |
NRF24 |
Misc Options → NRF24 Options |
NFC (PN532) |
NFC Options |
GPS |
GPS Options |
IR |
Infrared Options |
The Kconfig defaults for a CC1101 are MOSI 18, MISO 38, SCK 40, CSN 39, GDO0 41, and GDO2 disabled (-1). These are generic defaults, not a wiring recommendation for any specific board — confirm against your board’s own configuration before connecting anything.
## Module wiring reference
These are the signals each module needs. Match them to the pin numbers from the section above.
### CC1101 (SubGHz)
CC1101 pin |
Connects to |
VCC |
3.3 V |
GND |
GND |
MOSI / SI |
ESP32 MOSI |
MISO / SO |
ESP32 MISO |
SCK / SCLK |
ESP32 SCK |
CSN / CS |
ESP32 chip select |
GDO0 |
ESP32 interrupt pin |
GDO2 |
Optional (usually left unconnected) |
Attach a frequency-matched antenna before transmitting. Powering a CC1101 without an antenna can damage the module’s output stage.
### NRF24L01+
NRF24 pin |
Connects to |
VCC |
3.3 V (see note) |
GND |
GND |
MOSI |
ESP32 MOSI |
MISO |
ESP32 MISO |
SCK |
ESP32 SCK |
CSN |
ESP32 chip select |
CE |
ESP32 CE pin |
Note: the PA+LNA versions of the NRF24 draw far more current than the plain modules. A weak 3.3 V supply causes “radio not responding” failures that look like wiring bugs — add a decoupling capacitor across VCC/GND, or power it from a dedicated 3.3 V regulator.
### PN532 (NFC)
Most PN532 modules support I2C, SPI, and UART, and the onboard DIP switches select the mode. GhostESP uses I2C for PN532:
PN532 pin |
Connects to |
VCC |
3.3 V |
GND |
GND |
SDA |
ESP32 SDA |
SCL |
ESP32 SCL |
IRQ |
Optional |
RST |
Optional |
Set the module’s switches to I2C before wiring. A PN532 left in SPI or UART mode will not respond.
### GPS
GPS modules are UART devices. Cross the lines:
GPS pin |
Connects to |
TX |
ESP32 RX |
RX |
ESP32 TX |
VCC |
3.3 V |
GND |
GND |
Most modules default to 9600 baud. Some need a battery or a clear view of the sky before they output a fix — no data indoors is normal.
## Verified board wiring
These pinouts are documented elsewhere in the docs and are safe to follow directly.
### Flipper Zero to ESP32
ESP32 pin |
Flipper GPIO pin |
TX |
GPIO 13 or 15 |
RX |
GPIO 14 or 16 |
See the [Flipper app connection guide](/latest/flipper-app/connection/) for the full setup.
### GhostLink (two GhostESP boards)
Signal |
Connection |
TX of Device A |
RX of Device B (GPIO 6 → GPIO 7; 17 → 16 on base ESP32 models) |
RX of Device A |
TX of Device B (GPIO 7 → GPIO 6; 16 → 17 on base ESP32 models) |
See [GhostLink](/latest/getting-started/dual-communication/) for pairing and transport setup.
### GhostLink P1
The GhostLink P1 handheld has a complete, board-specific wiring map for its display, joystick, SD card, and charging circuit in its [owner’s guide](/latest/hardware/ghostlink-p1/).
## Troubleshooting
- Module not detected: confirm 3.3 V power first, then check that MOSI and MISO are not swapped. Swapped data lines are the most common SPI wiring mistake.
- One module works, another does not: modules on a shared SPI bus must each have their own chip-select pin, and only one may be active at a time. Boards that share a bus (the TEmbed C1101 is one) hold unused CS pins high to avoid conflicts.
- Works until you start a Wi-Fi or BLE task: radios compete for power and pins. See [Control methods](/latest/getting-started/control-methods/) for what can run at the same time.
- Pins keep resetting after reboot: you changed them at runtime but did not run sd_save_config, or the build config overrides them.
## Related tasks
- [Supported Hardware](/latest/getting-started/supported-hardware/)
- [SD card storage](/latest/getting-started/sd-card/)
- [Custom board configurations](/latest/development/custom-board-configs/)
- [Command line reference](/latest/getting-started/command-line-reference/)