IoT-devices, LLCFunctionality
The keypad module connects to the main controller via a 4-wire I2C bus interface and provides the following functions:
- Data entry with a five-button keyboard (left, right, down, up, OK);
- Data output to RGB LED;
- Output of sound sequences to the active indicator of the buzzer type;
I2C bus input and output through ports. Input for connection to MCU and output - for connection of any external devices that support the I2C specification.
Thanks to the use of the I2C bus and the MCP23017 port expander, GPIO savings of the main controller and the ability to input and output information in a user-friendly way are achieved. The rest of 7 GPIOs are connected to separate pin connectors for additional I / O signals connection according to the user's design. Int A & Int B output signals are available - can be used for interrupt processing when the state of the module inputs changes.
Application
I2CUI4_V1 keypad will be convenient to use as a control panel and status display on user devices
- electronic clocks,
- radiation level dosimeters,
- smart outlets,
- thermostats,
- multimedia and audio devices,
- weather stations and others.
Usecase example
The image shows the application of another of our I2CUI3_V1 modules in a DIY GGreg20_V3-based Geiger counter. The I2CUI4_V1 module is an updated and more versatile version that allows you to build convenient and reliable DIY and IoT solutions for most platforms.
Compatibility
Compatible with controllers and platforms:
- Arduino,
- ESP12.OLED_V1,
- NodeMCU board (based on ESP8266-12),
- modules on the ESP8266EX chip,
- ESP32,
- or others powered by 1.8 - 5.5 V.
Integration into Home Assistant (with ESPHome plugin), Blynk, OpenHab, Node-RED is possible.
Minor and major versions of the module
Unlike the minor version I2CUI3_V1, the I2CUI4_V1 user interface module uses a widely supported 16-bit MCP23017 port expander. This makes it possible to use this module in IoT devices for easy integration in Home Assistant, Arduino and many others.
Chips of user interface modules:
- I2CUI3_V1 - 8-bit, I2C, PCA9538, 2^3 GPIOs;
- I2CUI4_V1 - 16-bit, I2C, MCP23017, 2^4 GPIOs.
The major version of I2CUI4_V1 has the following features:
- single digital interface - 2 x I2C (input / output) ports;
- 5 “joystick” buttons; sound indicator; RGB LED indicator;
- selection of one of 8 module addresses on the I2C bus via solred-pads;
- 7 free GPIOs are connected to separate pin connectors.
Driver-level support
Support for the MCP23017 chip at the driver level is stated in particular by the following platforms:
Assignment of module ports
The following ports are provided on the I2CUI4_V1 module board:
| Port Name | Assignment | Logic |
|---|---|---|
| GPIO 0 (GPB0) | Buzzer on board | 3V3 or 5V active high |
| GPIO 1 (GPB1) | Free, for user extensions | 3V3 or 5V active low |
| GPIO 2 (GPB2) | Free, for user extensions | 3V3 or 5V active low |
| GPIO 3 (GPB3) | Free, for user extensions | 3V3 or 5V active low |
| GPIO 4 (GPB4) | Free, for user extensions | 3V3 or 5V active low |
| GPIO 5 (GPB5) | Free, for user extensions | 3V3 or 5V active low |
| GPIO 6 (GPB6) | Free, for user extensions | 3V3 or 5V active low |
| GPIO 7 (GPB7) | Free, for user extensions | 3V3 or 5V active low |
| GPIO 8 (GPA0) | LED - Blue on board | 3V3 or 5V active high |
| GPIO 9 (GPA1) | LED - Green on board | 3V3 or 5V active high |
| GPIO 10 (GPA2) | LED - Red on board | 3V3 or 5V active high |
| GPIO 11 (GPA3) | Key Up on board | 3V3 or 5V active high |
| GPIO 12 (GPA4) | Key Down on board | 3V3 or 5V active high |
| GPIO 13 (GPA5) | Key Left on board | 3V3 or 5V active high |
| GPIO 14 (GPA6) | Key Right on board | 3V3 or 5V active high |
| GPIO 15 (GPA7) | Key OK on board | 3V3 or 5V active high |
| A0 | I2C address bit 0 | GND=0; VDD=1, by default 0 |
| A1 | I2C address bit 1 | GND=0; VDD=1, by default 0 |
| A2 | I2C address bit 2 | GND=0; VDD=1, by default 0 |
| IntA | Interrupt for GPIO group A | 3V3 or 5V active low |
| IntB | Interrupt for GPIO group B | 3V3 or 5V active low |
| I2C | SDA I2C I/O | 3V3 or 5V active low |
| I2C | SCL I2C I/O | 3V3 or 5V active low |
| 3V3 | Power | 1.8-5.5 V |
| GND | Common ground |
Power supply and consumption
The power supply of the module is possible in the range of voltages of 1.8 - 5,5 volts. The current consumption of the I2CUI4 module at rest is about 1 microampere. In the case of simultaneous data output to R + G + B + buzzer, the maximum current consumption can reach 20 milliamperes.
Addressing on the I2C bus
The address of the module has a fixed and variable part:
| Fixed address part | Variable (selectable) address part |
|---|---|
| 0 1 0 0 | A2 A1 A0 |
The address of the module I2CUI4_V1 is selected in accordance with the documentation on the chip MCP23017 because it is this chip of the module that interacts with the main controller via the I2C bus.
Interrupt handling
The module has two interrupt channels: Int A and Int B. All processing and logic (active-low) correspond to the documentation for the MCP23017 chip. Interrupt processing is provided for the master controller to monitor changes in GPIO states set to input mode.
Note: When you want to process interrupts from one combined INT and not from each separately INTA and INTB, the client must solder to connect the INTA and INTB pads.
According to the design of the interface module I2CUI4_V1, input mode:
- must be set for:
- GPIO 11 (GPA3) - Key Up on board;
- GPIO 12 (GPA4) - Key Down on board;
- GPIO 13 (GPA5) - Key Left on board;
- GPIO 14 (GPA6) - Key Right on board;
- GPIO 15 (GPA7) - Key OK on board.
- can be set for spare GPIO ports if used by the user as inputs: GPIO 1 (GPB1), GPIO 2 (GPB2), GPIO 3 (GPB3), GPIO 4 (GPB4), GPIO 5 (GPB5), GPIO 6 (GPB6) ), GPIO 7 (GPB7).
Ports GPIO 0 (GPB0) Buzzer on board, GPIO 8 (GPA0) LED - Blue on board, GPIO 9 (GPA1) LED - Green on board, GPIO 10 (GPA2) LED - Red on board - work on the module as outputs.
Module dimensions
The dimensions of the module board are 50 x 52 mm. Module height (Z): 15 mm.
Product kit sets
The module is delivered in the following sets:
- Basic set 1 pc - I2CUI4_V1 User Interface I2C keypad module.
- Basic + Connectors set ( Note: The user receives a module with installed connectors.)
- 1 pc - Basic set;
- Connectors:
- JST XH 2,54 2p - 1 pc.:
- JST XH 2,54 4p - 4 pc.
- Basic + Connectors + Cables set ( Note: The user receives a module with installed connectors and selected cables when ordering.)
- 1 pc - Basic + Connectors set;
- Cables:
- JST XH 2,54 4p - JST XH 2,54 4p - 1 pc.;
- JST XH 2,54 2p - JST XH 2,54 2p - 1 pc.;
- JST XH 2,54 4p - Dupont 4p - 1 pc.;
- JST XH 2,54 2p - Dupont 2p - 1 pc.