Difference between revisions of "Protocol decoder:Rfm12"

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{{Infobox protocol decoder
{{Infobox protocol decoder
| id              = rfm12
| id              = rfm12
| name            = RFM12
| name            = RFM12 control protocol
| description    = 433, 868 and 915MHz transceiver chip
| description    = HopeRF RFM12 wireless transceiver control protocol
| status          = supported
| status          = supported
| license        = GPLv2+
| license        = GPLv2+
| source_code_dir = rfm12
| source_code_dir = rfm12
| image          = [[File:RFM12.png|250px]]
| image          = [[File:RFM12.png|250px]]
| input          = spi
| input          = [[Protocol decoder:spi|spi]]
| output          = rfm12
| output          = rfm12
| probes          = —
| probes          = —
| optional_probes = —
| optional_probes = —
| options        = —
}}
}}


The '''rfm12''' protocol decoder supports the protocol spoken by the HopeRF [http://www.hoperf.com/rf/fsk_module/RFM12B.htm RFM12] transceiver chips.
The '''rfm12''' decoder supports the control protocol for the [http://www.hoperf.com/rf/fsk_module/RFM12B.htm HopeRF RFM12] transceiver chip.
 
== Hardware ==
 
RFM12B is a single chip, low power, multi-channel FSK transceiver designed for use in applications requiring FCC or ETSI conformance for unlicensed use in the 433MHz, 868MHz and 915MHz bands.
 
These modules come in three different form factors, DIP package (shown on the photo in the upper right) and two SMD packages: S1 with normal crystal and S2 with low-profile crystal.
 
<gallery>
File:Hoperf rfm12bs top.jpg|<small>RFM12B-S, top</small>
File:Hoperf rfm12bs bottom.jpg|<small>RFM12B-S, bottom</small>
</gallery>
 
Pins:
 
{| border="0" style="font-size: smaller" class="alternategrey sigroktable sortable"
|-
!Name
!Function
 
|-
| nINT/VDI
| Interrupt input (active low) / valid data indicator
 
|-
| VDD
| Positive power supply
 
|-
| SDI
| SPI data input
 
|-
| SCK
| SPI clock input
 
|-
| nSEL
| Chip select (active low)
 
|-
| SDO
| SPI data output
 
|-
| nIRQ
| Interrupt request output (active low)
 
|-
| FSK/DATA/nFFS
| Transmit FSK data input / received data output (FIFO not used) / FIFO select
 
|-
| DCLK/CFIL/FFIT
| Clock output (no FIFO) / external filter capacitor (analog mode) / FIFO interrupts (active high)
 
|-
| CLK
| Clock output for external microcontroller
 
|-
| nRES
| Reset output (active low)
 
|-
| GND
| Power ground
|}
 
== Protocol ==
 
In minimal configuration the chip uses the standard SPI protocol on pins SDI, SDO, SCK and nSEL. You can optionally connect nIRQ which will be pulled low by the transceiver to trigger interrupt requests. There is also an option to transmit and receive the data without the SPI protocol overhead using the dedicated DATA and DCLK pins.
 
SPI communication happens in a fixed length of 16-bit chunks. During each exchange the microcontroller first sends the command and then receives the response.
 
== Decoder ==
 
The '''rfm12''' decoder stacks on top of the [[Protocol decoder:spi|SPI decoder]] and decodes the SPI exchanges. It shows what commands were sent to the chip and decodes the responses. It also interprets the commands and shows what happened to the chip.
 
Some decoded commands in [[PulseView]]:
 
<gallery>
File:RFM12_status_command.png|<small>Status command.</small>
File:RFM12_receiver_control.png|<small>Receiver control command.</small>
</gallery>
 
== Resources ==
 
* [http://www.hoperf.com/rf/fsk_module/RFM12B.htm RFM12 page on HopeRF site]
* [http://www.hoperf.com/upload/rf/RFM12.pdf RFM12 datasheet]
* [http://www.hoperf.com/upload/rf/RFM12B.pdf RFM12B datasheet]
* [https://www.sparkfun.com/datasheets/Wireless/General/RF12-IC.pdf RF12 IC datasheet]


[[Category:Protocol decoder]]
[[Category:Protocol decoder]]
[[Category:SPI]]
[[Category:SPI]]

Latest revision as of 23:56, 2 April 2015

rfm12
RFM12.png
Name RFM12 control protocol
Description HopeRF RFM12 wireless transceiver control protocol
Status supported
License GPLv2+
Source code decoders/rfm12
Input spi
Output rfm12
Probes —
Optional probes —
Options —

The rfm12 decoder supports the control protocol for the HopeRF RFM12 transceiver chip.

Hardware

RFM12B is a single chip, low power, multi-channel FSK transceiver designed for use in applications requiring FCC or ETSI conformance for unlicensed use in the 433MHz, 868MHz and 915MHz bands.

These modules come in three different form factors, DIP package (shown on the photo in the upper right) and two SMD packages: S1 with normal crystal and S2 with low-profile crystal.

  • RFM12B-S, top

  • RFM12B-S, bottom

Pins:

Name Function
nINT/VDI Interrupt input (active low) / valid data indicator
VDD Positive power supply
SDI SPI data input
SCK SPI clock input
nSEL Chip select (active low)
SDO SPI data output
nIRQ Interrupt request output (active low)
FSK/DATA/nFFS Transmit FSK data input / received data output (FIFO not used) / FIFO select
DCLK/CFIL/FFIT Clock output (no FIFO) / external filter capacitor (analog mode) / FIFO interrupts (active high)
CLK Clock output for external microcontroller
nRES Reset output (active low)
GND Power ground

Protocol

In minimal configuration the chip uses the standard SPI protocol on pins SDI, SDO, SCK and nSEL. You can optionally connect nIRQ which will be pulled low by the transceiver to trigger interrupt requests. There is also an option to transmit and receive the data without the SPI protocol overhead using the dedicated DATA and DCLK pins.

SPI communication happens in a fixed length of 16-bit chunks. During each exchange the microcontroller first sends the command and then receives the response.

Decoder

The rfm12 decoder stacks on top of the SPI decoder and decodes the SPI exchanges. It shows what commands were sent to the chip and decodes the responses. It also interprets the commands and shows what happened to the chip.

Some decoded commands in PulseView:

  • Status command.

  • Receiver control command.

Resources

Retrieved from "https://sigrok.org/w/index.php?title=Protocol_decoder:Rfm12&oldid=10722"