RFM12B FIFO µSD Atmega328 AVR ARM PIC 433MHZ RF Wireless Transceiver

RFM12B FIFO µSD Atmega328 AVR ARM PIC 433MHZ RF Wireless Transceiver RFM12B

Product	Freq	Power supply	Data-rate(kbps)	Output Power(MAX)	Sensitivity	Tx Current(MAX)	Work Current	stand by current
HYRM12B	433MHz	2.2-3.8V	115.2	5dBm at 433MHz	-105dBm at 433MHz	22mA at 433MHz	11mA at 433MHz	≤0.3µA

 

GENERAL
HYRM12B features a completely  integrated PLL for easy RF design, and its rapid settling time allows for fast frequency-hopping, bypassing multipath fading and interference to achieve robust wireless links. The PLL’s high resolution allo ws the usage of multiple channels in any of the bands. The receiver baseband bandwidth (BW) is programmable  to accommodate various deviation, data rate and crystal tolerance requirements. The transceiver employs the Zero-IF approach with I/Q demodulation. Consequently, no external components (except crystal and decoupling) are needed in most applications.   HYRM12B  dramatically  reduces the load on the  microcontroller with the integrated digital data processi ng features: data filtering, clock recovery, data pattern recognition,  integrated FIFO and TX data register. The automatic frequency control (AFC) feature allows the use of a low accuracy (low cost) crystal. To minimize the  system cost,HYRM12B can provide a clock signal for the microcontroller, avoiding the need for two crystals.   For low power applications,  HYRM12B supports low duty cycle operation based on the internal wake-up timer Introduction

HYRM12B tranceiver module has become quite popular recently due to its low price comparing to other modules on the market. But many people find it hard to make these tranceivers work (mainly because of buggy programming guide provided by manufacturer, I guess...). This short article contains compact and simple code that can be used just to get these modules running for the first time. It is based on manufacturer's examle code with slight (but crucial) changes.

Schematic

To interface HYRM12B modules I used Atmel's ATtiny2313. Recommended power supply for the module is 3.8V so I decided to power both the processor and the module from 3.3V. It can be a problem with the Mega family as you will need "L" version then. Some people claim that they run those modules from 5V and everything's fine. The other solution is splitted power supply (5V for processor and 3.3V for HYRM12B ) but resistors are needed on IO pins (5kohm or so) in this case. Implementing SPI interface doesn't require strict time delays or clock stability so processor is running on the 8MHz internal RC oscillator.

 

FEATURES

• Fully integrated (low BOM, easy design-in)
• No alignment required in production
• Fast-settling, programmable, high-resolution PLL synthesizer
• Fast frequency-hopping capability
• High bit rate (up to 115.2 kbps in digital mode)
• Direct differential antenna input/output
• Integrated power amplifier
• Programmable TX frequency deviation (15 to 240 kHz)
• Programmable RX baseband bandwidth (67 to 400 kHz)
• Analog and digital RSSI outputs
• Automatic frequency control (AFC)
• Data quality detection (DQD)
• Internal data filtering and clock recovery
• RX synchron pattern recognition
• SPI compatible serial control interface
• Clock and reset signals for microcontroller
• 16 bit RX Data FIFO
• Two 8 bit TX data registers
• Low power duty cycle mode
• Standard 10 MHz crystal reference
• Wake-up timer
• 2.2 to 3.8 V supply voltage
• Low power consumption
• Low standby current (0.3µA)
• Supports very short packets (down to 3 bytes)
• Excellent temperature stability of the RF parameters
• 433MHZ​

Application  

• Home security and alarm 
• Remote  control, keyless entry  
• Wireless keyboard/mouse and othe
• Toy controls 
• Remote  keyless entry 
• Tire pressure monitoring 
• Telemetry 
• Personal/patient  data logging 
• Remote automatic meter reading

Antenna 

433 1/4 wave = 164.7mm

433 1/2 wave = 329.4mm

433 full wave = 692.7mm

Arduino Uno Connections

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