Comments on: RFM12 Tutorial – Part2

By: RFM12 Tutorial – Part1

RFM12 Tutorial – Part1 — Mon, 26 Jul 2010 14:00:04 +0000

[...] Next – Part 2 [...]

By: Stephen Eaton

Stephen Eaton — Thu, 22 Jul 2010 03:25:26 +0000

@geo

The RFM12B has 5V tolerant I/O, however in saying that I wouldn’t leave it running at 5V for an application as it may shorten it’s life. When I first started development I didn’t use shifters etc and all ran ok.

By: geo

geo — Sat, 17 Jul 2010 06:44:39 +0000

Hi,
I am trying to interface a at89c52(5V) with the RFM12B(~3.6V) module. Whether I need to take care about including any delimiting resistors or other kind of level shifters between the SPI bus pins.
thanks in advance
Geo

By: Stephen Eaton

Stephen Eaton — Wed, 30 Jun 2010 02:28:36 +0000

@Nart_schinakow

I would suggest you look at other examples of code other than the ones supplied from HopeRF. I had no end of problems with them. However in saying that I did have some problems getting the hardware SPI working with the PIC and the RFM12B, this was a couple of years ago though.

By: Nart_schinakow

Nart_schinakow — Thu, 17 Jun 2010 13:15:48 +0000

Hello Stephen,
Really thanks for these nice tutorials!!!
i thought i gave up on that rfm12!!! i used the hm-tr from hope rf wich uses standrd rs232 protocol but they are very expensive !!! my question is if i want to use the hardware spi will the code be the same as the programming guide??

Note: I am Using Mikroc And has an spi library (hardware)(Pic16f876a)

Thanks Alot Stephen .

By: laci

laci — Thu, 03 Jun 2010 18:11:51 +0000

As soon as I have some spare time, i will get to the bottom of this issue , and write my own tutorial and post my entire software on a blog.

By: realheaven

realheaven — Thu, 03 Jun 2010 11:41:45 +0000

@ laci 108

hi laci, you should read this :
http://zenburn.net/~goroux/rfm12b/rfm12b_and_avr-%20quick_start.pdf

i think it’ll help you to solve your problem.

hope you success!

By: laci

laci — Wed, 02 Jun 2010 18:38:45 +0000

I will make a more thorough debug, maybe I made some stupid mistake somewhere… until then I remain skeptic just won’t switch between tx/rx remains blocked somewhere

By: realheaven

realheaven — Tue, 01 Jun 2010 13:48:51 +0000

@ laci 106

at first, if you want one node at TX mode then you should init it @ TX mode by writeCmd(0×8239). Next, if you want it at RX mode you should switch it to RX mode by writeCmd(0×8299).
You can also test the TX RX mode with one simple test. For example, you have 2 node A & B.
1. A (TX) —> B(RX)
2. A(TX–>RX) & B(RX–>TX)
3. B(TX)–>A(RX)

A sends out a byte to B, A immediately switches to RX mode; if B (@ RX)receives a byte and check if it’s from A then B switches to TX mode and sends out a byte; @ A you can easily check the data from B by send it to PC using RS232.

ps : you should test both two nodes that can transmit and receive data first to be sure that there’s no fault at any stage of the process.

good luck!

(feel free asking, rite!)

By: laci

laci — Mon, 31 May 2010 10:16:10 +0000

@realheaven

The TX/RX switching won’t work, at start up I can switch to TX(no received data yet), it sends out the data, after I start to receive the RX mode won’t gather any data, and I can’t switch back to TX mode.

See my previous posts, I even posted the mode select function.