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Interfaces

40-Pin Header (J1)

iChidori-Crest connects to the Raspberry Pi via the standard 40-pin GPIO header.

HAT with Raspberry Pi

Connector type: 2×20, 2.54 mm Pin socket

Mating connector: Raspberry Pi 4/5 Model B built-in 40-pin GPIO header

40-Pin GPIO Header Assignments

40-pin Header

40-pin Header

UART Interfaces Summary

Interface Raspberry Pi Mosaic G5 LTE Module
G5 UART UART0/1 (GPIO14/15) COM1 —
G5 UART UART4 (GPIO8/9/10/11) COM2 —
LTE UART UART3 (GPIO4/5/6/7) — UART

Serial port configuration

Raspberry Pi 4/5 has UART0–UART5, but most are disabled by default and require additional configuration.

To enable UART on GPIO14/GPIO15 (TXD/RXD) for mosaic-G5 COM1:

  1. Run sudo raspi-config
  2. Select Interface Options → Serial Port
  3. Set Login shell over serial → No
  4. Set Serial port hardware → Yes
  5. Exit and reboot

After reboot, verify which UART type is assigned to the primary serial port:

ls -l /dev/serial0

On Raspberry Pi 4/5, /dev/ttyAMA* represents PL011 UARTs and /dev/ttyS* represents the mini UART.

Use a PL011 UART (/dev/ttyAMA*) for communication with the mosaic-G5.
PL011 UARTs have a dedicated clock and provide stable baud rates at higher speeds. The mini UART (/dev/ttyS0) shares the CPU clock and is not recommended for GNSS applications.

If serial0 points to /dev/ttyS0, reassign it to PL011 by adding the following line to /boot/firmware/config.txt:

dtoverlay=disable-bt

This disables Bluetooth and frees the PL011 UART for GPIO14/GPIO15. Reboot and verify again:

ls -l /dev/serial0

Confirm that serial0 now points to /dev/ttyAMA0 before proceeding.

Power Pins

Pin Function
2, 4 5V from Pi
6, 9, 14, 20, 25, 30, 34, 39 GND

52-Pin mPCIe Slot (J2)

iChidori-Crest provides a standard Mini PCIe (mPCIe) slot for LTE modems.
Connector Attend Technology 119A-80A00-R02
Type 52-pin Mini PCIe edge connector, 0.8 mm pitch
Retention 119A-NUT-80-R02 standoff nut, secured with M2×0.4 screw, 4.0 mm length

mPCIe Slot

52-Pin mPCIe Assignments

mPCIe Pin Assignment mPCIe Pin Assignment

Expansion 6-Pin Header (J8)

Connector type: Conn_01×06, 2.54 mm pin header

J8 Header

Pin Signal Description
1 PI_GPIO13 Raspberry Pi GPIO13
2 LTE_WAKE# LTE modem wake signal (active low)
3 PI_GPIO12 Raspberry Pi GPIO12
4 +3V3 3.3V power
5 WP EEPROM Write protect
6 GND Ground

USB device Interface (J5)

Connector type: USB Type-C, USB 2.0

USB Connector

The USB-C connector serves as the primary power supply and data interface.

An internal 2-port USB hub routes the single connector to two independent device interfaces:

Port Connected Device
1 Mosaic G5 USB device interface
2 LTE mPCIe USB device interface

GNSS Antenna Connectors

iChidori-Crest provides two MMCX antenna connectors for the mosaic-G5 receiver.

GNSS Antenna Connectors

Antenna Port Table

Antenna supply voltage

Both ports supply V_ANT = 3.3 V DC to power active GNSS antennas.

Antenna Mode Setting

iChidori-Crest is offered in variants that differ in antenna capability:

Variant Antenna Mode
P1, P3 Single-antenna only
P3H, P6 Single-antenna or dual-antenna (heading)

Use the following commands to check or configure the antenna mode:

  • getFrontendMode — query the current antenna mode
  • setFrontendMode, SingleAnt — configure single-antenna mode at the next reboot
  • setFrontendMode, DualAnt — configure dual-antenna (heading) mode at the next reboot
  • exeCopyConfigFile, Current, Boot — save the configuration to the boot file
  • exeResetReceiver, Hard, none — reboot to apply

Connect an active antenna to ANT_1 (MAIN). The ANT_1 input is DC-biased and ESD-protected; an active antenna can be connected directly without additional components. Leave ANT_2 (AUX) open when operating in single-antenna mode.

SD Logging (J4)

A physical SD card slot is provided for direct on-board logging by the mosaic-G5 receiver.

SD Card Connector

Note

This SD logging capability is intended for evaluation and debugging purposes only; it is not recommended for use in production/deployed systems.

SIM Card (J10)

The board provides a Nano SIM socket for the LTE module.

SIM Card Connector

SIM slot on the LTE card

If the installed LTE card has its own SIM slot, the SIM can be inserted directly into that slot instead of the Nano SIM socket on the iChidori-Crest. This allows SIM sizes other than Nano (for example Micro or Mini, depending on the card) to be used. The supported SIM types therefore depend on the LTE card in use.

QWIIC Connector (J11)

A QWIIC connector is provided for expansion I2C communication.

QWIIC Connector

Pin Signal
1 GND
2 3.3V
3 SDA
4 SCL

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