Combining Leaves and Choosing a Power Supply

When adding a sensor or communication leaf, check MCU and program → power → pin usage → I2C addresses → component layout, in that order. Find the functions you need in the Leaf List and open each leaf’s specifications and examples.

Matching bus contacts do not mean that every leaf can be used simultaneously. The following steps help you assess a configuration; they are not a guarantee of operation or a compatibility matrix for every product.

1. Choose the MCU and Program

Start with the leaves, libraries, and development environment specified in an example. Even when model names are similar, changing the MCU or sensor may require changes to the program.

What to check	Example
MCU model and board settings	Distinguish AP01, AP03, AP03B, AP02, and other models, and check the MCU’s development environment
Sensor model and library	AI05 uses different sensors from AI01, so AI01 examples cannot be used unchanged
Upload method and interface leaf	Uploading to AP01 through AZ01C requires a manual reset
Signal changes between revisions	AP03B disconnects D9 from the MCU when BOOT0 is High

2. Choose the Power Supply

Choose a power supply by battery input voltage, output voltage, connector, and the current required by the load. Distinguish peak current, such as during communication startup, from average current, which affects battery life.

What to check	Reference and notes
Battery type and input range	Check specifications for AV01 CR2032 or AV06 1.8V–5.5V
Peak current during wireless communication	AC08 LTE-M Mary specifies AV06 because its peak current is 400mA
Battery and connector	AV06 uses JST PH; AV04 uses JST SH. Check which power leaf the battery holder connects to
USB and battery used together	Read the AZ01C power-state explanation and check simultaneous supply conditions on the other power leaf too
Current estimation and measurement	See Low-Power Design and Current Measurement with AX05B

A power IC’s maximum output current alone does not tell you whether the connected battery can supply it. Check the battery specifications and the voltage and load conditions you will use. Configurations with both USB and a battery also require checking the power paths.

3. Compare GPIO and Communication Pins

Compare the Leafony Bus contact table with each leaf’s pin assignment. GPIO means general-purpose input/output; a leaf may use these pins for UART, SPI, interrupts, or power control.

1. List the inputs, outputs, and signal names used by each leaf.
2. If leaves use the same bus contact, check whether the signal can be shared and whether separately controlled outputs would conflict.
3. Match MCU port names to the pin assignments and communication ports in the program.
4. Check each device’s input/output voltages against the connected device’s allowed conditions. Do not confuse the power input voltage range with the allowable GPIO voltage.

The Pin Assignment Editor can display and save pin usage for up to eight leaves. It does not determine whether a connection is valid. Blank entries in a preset do not guarantee that a contact is unused or available for another purpose.

4. Check I2C Addresses and Pull-Ups

When leaves are stacked, I2C devices connected to SDA/SCL share the same bus. Use the I2C Address Map to compare addresses, distinguishing standard components, optional components, and reserved addresses.

Example combination	What to check
AI05 and AX06	The LIS2DW12 and I/O expander both use 0x18
Any two of AC04, AC08, and AC09	Control I/O expanders share address 0x21
Multiple power leaves	Some configurations share battery voltage monitor address 0x50. Check competing power sources separately

Do not assume that devices with the same address can be connected unchanged and controlled individually. Whether an address can be changed depends on the device and its assembly.

Check the I2C pull-up resistors too. For example, AI05’s R18 and R19 are not fitted; an AI05/AP03 configuration uses AP03’s pull-ups. With another MCU or external circuit, check the pull-up voltage and resistors in each circuit.

5. Check Clearance and Stacking Order

Even when leaves share the same bus, tall components or battery holders may touch an adjacent leaf. Follow the example’s stacking order and insert an AX04 Spacer where specified.

For communication leaves, also allow access to the antenna position, SIM slot, USB connector, and other connections. See Assembling and Replacing Leaves for assembly steps.

Record and Test Your Configuration

Test sensors and communication individually with basic examples before running your intended program on a new configuration. Record the following so that the result can be reproduced.

Item	What to record
Hardware	Leaf models and revisions, stacking order from top to bottom, spacers, and connection photos
Power	Battery or USB source, voltage, and power switch positions
Software	Example version, board settings, libraries, and pin assignments
Results	Sensor readings or communication logs, measured current, and steps that caused problems

If some conditions remain unclear, contact support (Japanese) with your configuration and the checks you have tried.