Atmel ATtiny44 Modbus RTU Slave Project
(Or how to add Modbus RTU protocol to a device for 1 euro…)

Modbus RTU Slave project based on ATtiny44 processor .
You can use the low cost uController to add Modbus protocol to your device.
ATTiny44 has 8 ADC chanels with 10 bits resolutions.
You can mix the ADC inputs with digital inputs.

The project uses one ADC an 4 digital inputs and RS232/RS485 communication.
The first input of ADC is available at Modbus address 40001 as float value (2 registers).
The voltage input form 0 .. 1.1 V from input PA0 is scaled to 0..100%

The digital inputs from PA1..PA4 are available at Modbus addresse 10001,10002,1003,10004

Communication parameters : Slave address 1 @ 9600, 8N1

Circuit for the project :

ATTINY44 Modbus RTU

[ Download Atmel ATtiny44 Modbus RTU Slave ]

Atmel ATMega128 Modbus TCP/IP server

Modbus TCP/IP Server project based on MMNET01 board with ATMega128 processor .

You can use the low cost board to add Modbus TCP/IP protocol to your device.
ATMega128 has I2C, SPI, 2 UARTS, 8 ADC chanels with 10 bits resolutions.
You can mix the ADC inputs with digital inputs.

The project uses Nut/OS – simple real time operating system.

The temperature from 1-wire Digital Thermometer DS18B20, you can read via Modbus TCP/IP from register 40001/40002 (float value).

Circuit for the connection DS18B20 to MMNET01

Modbus TCP/IP

[ Download Atmel Modbus TCP/IP Server ]