3 ATtiny85 Pins Control of the - Nrf24L01 - التحكم بثلاثة دبابيس فى
by abdelhak_bourdim in Circuits > Wireless
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3 ATtiny85 Pins Control of the - Nrf24L01 - التحكم بثلاثة دبابيس فى
بسم الله الرحمن الرحيم
Introduction
The ATTiny85 is a high-performance, low-power Microchip 8-bit AVR RISC-based microcontroller combines 8KB ISP flash memory, 512B EEPROM, 512-Byte SRAM, 6 general purpose I/O lines.
One I/O line is configured as a RESET pin. We are left with only 5 I/O lines.
On the other hand, The nRF24L01 is a single chip 2.4GHz transceiver. It is configured and operated through a Serial Peripheral Interface (SPI - 5 I/O lines).
Interfacing the ATTiny85 with nRF24L01 leaves no room to add even a simple switch.
This article revisits the "Nerd Ralph original article" - http://nerdralph.blogspot.com/2014/01/nrf24l01-con... - how to use just 3 pins of the ATTiny85 to control the transceiver.
This article gathers all the information spread over many articles treating the case in one place.
PCB Design
Kicad is used to design this simple board.
Coding
Two sketches are freely available for the tests.
- Transmitter sketch : To be flashed to the ATTiny85 board
- Receiver sketch : To be flashed to our ATMega328PB sniffer board
Assembly
A simple board means easy assembly.
TIP1 - ATTiny80 Board Configuration
The ATTiny85 should be configured with 1 MHZ internal frequency to achive successful communication.
Slowing down the SPI bus, leaves enough time for the RC circuit to charge and discharge completely to mangage perfectly the CSN I/O line.
TIP2 - MISO -> MOSI and MOSI -> MISO
When used as an SPI master
- ATTINY85 MISO -> Nrf24L01 MOSI
- ATTINY85 MOSI -> Nrf24L01 MISO
When used for ISP programming
- ATTINY85 MISO -> Nrf24L01 MISO
- ATTINY85 MOSI -> Nrf24L01 MOSI
Enjoy
A video is embedded to demostrate the use case.
الحمد لله رب العالمين