Is the WIRELESS forum monitored ?

[sid1202]

I've been trying to get answers about the RMF69HCW Feather and I posted in wireless but I've been talking to myself.

I tried posting on LowPowerLab and RadioHead's forums, but my questions are to basic and I feel I'm getting a cold shoulder.

I've posted here in the wireless forum with no replies.

Is it the way I formulate my questions in English ? Am I just not looking at the right place ?

Please can anyone help ?

Sidney

[adafruit_support_rick]

Sorry that no one has gotten back to you. What questions do you have?

[sid1202]

I have several questions about different mechanisms the radio offers but lets tackle them one at a time. I've been reading the datasheets, code exemples and the code from both LowPowerLab and RadioHead. so here goes my first question:

I'm trying to understand how to configure the radio for something else that the default. I've read the datasheets but they do not explain the relationship between dome of the configurations.The data sheet states that the radio can do up to 300kbps but the defaults are set at 4800kbps.Is there information on those relationships ?

[Franklin97355]

Which specific device are you asking about? We use modules and do not program the internals. The datasheets we have are here for you to read.

[sid1202]

Which specific device are you asking about? We use modules and do not program the internals. The datasheets we have are here for you to read.

Really ?

I've been trying to get answers about the RMF69HCW Feather... snip

and

I've been trying to get answers about the RMF69HCW Feather and the code from both LowPowerLab and RadioHead. so here goes my first question:

I'm trying to understand how to configure the radio for something else that the default. I've read the datasheets but they do not explain the relationship between dome of the configurations.The data sheet states that the radio can do up to 300kbps but the defaults are set at 4800kbps.Is there information on those relationships ?

Now I got to know, what the heck did I do wrong ? Was to obscure in my communications ? If so, please let me know so I can try to improve my English...

Regards

[sid1202]

Look, when even the radio gurus are having a hard time with the datasheet in figuring out what it means, how do you expect us to figure it out ?

https://lowpowerlab.com/forum/rf-range- ... ith-rfm69/

So, again, can someone actually help ?

[Franklin97355]

even the radio gurus are having a hard time with the datasheet

Let's hope someone does.

[adafruit_support_rick]

The datasheet is fairly clear. To set the bit rate, you need to write the bitrate registers. The effective bitrate is given by the FXOSC rate divided by the bitrate register setting. Section 3.3.2 gives some example bitrate settings. The bitrate registers are described on pages 63 and 64. The default register setting is 0x1A0B, and the nominal FXOSC rate is 32MHz. 0x1A0B = 6667. 32MHz/6667 = 4800Hz.

The library contains functions to read and write registers. For convenience, symbolic definitions of the registers are in the file RFM69registers.h.

[sid1202]

The datasheet is fairly clear. To set the bit rate, you need to write the bitrate registers.

Got that part.

The effective bitrate is given by the FXOSC rate divided by the bitrate register setting. Section 3.3.2 gives some example bitrate settings. The bitrate registers are described on pages 63 and 64. The default register setting is 0x1A0B, and the nominal FXOSC rate is 32MHz. 0x1A0B = 6667. 32MHz/6667 = 4800Hz..

This is the part I'm get confused about. When reading up on the subject seams that changing the bit rate (reg 0x03 & 0x04) needs to be matched by changes to the bandwidth (0x19), the frequency deviation (0x05 & 0x06) and the Channel Filter BW control (0x1A). Also may be required to tweak the Packet mode settings (0x37) and the Data operation mode and Modulation settings (0x02)

On page 20, the data sheet states some functions to calculate the Fdev "FDev = FStep x Fdev(13,0)" and a limit of "FDev - BR/2 <= 500kHz" And I have no idea what that means. I don't understand what the (13,0) stand for.

Then on page 64, for RegBitrateLsb if the Manshester encoding is enabled it says that BitRate = FXOSC / BitRate(15,0) Followed by Fdev = Fstep - Fdev(15,0) so its not (13,0) anymore ?

Not so clear for me. I'm not an electrical engineer... But that's not all

On page 67 about the RegRxBw, not that is definitely not clear, but from the table on page 20, I'd like to use FSK. As for RegAfcBw I couldn't find what the AFC is anymore. It must be defined somewhere but by the time I get here I forget what it means and I wouldn't know which parameter I should use.

On page 72 RegPacketConfig1 well finally this one I understand and I can tweak it.

So All I want it to maximize the transfer rate to transmit either a config file or a audio file (needs 64kbps ideally but can be less) across in a short burst to then go back to default settings. I can set the radio to continuous mode if need be and turn off whitening for the audio transfer.

But I need the set the radio at its highest capacity for that burst.

[adafruit_support_rick]

This is the part I'm get confused about. When reading up on the subject seams that changing the bit rate (reg 0x03 & 0x04) needs to be matched by changes to the bandwidth (0x19), the frequency deviation (0x05 & 0x06) and the Channel Filter BW control (0x1A). Also may be required to tweak the Packet mode settings (0x37) and the Data operation mode and Modulation settings (0x02)

Where did you see that? I'm not reading it that way. It looks to me like you simply change the bit rate.

On page 20, the data sheet states some functions to calculate the Fdev "FDev = FStep x Fdev(13,0)" and a limit of "FDev - BR/2 <= 500kHz" And I have no idea what that means. I don't understand what the (13,0) stand for.

The (13,0) refers to the relevant bits of the FDev register. The register is only 14 bits long.
So FStep is FStep = FXOSC/2^19. This comes out to a value of 64. FDev is FStep times whatever is in the low 14 bits of the Fdev register. FDev - bitrate/2 has to be <= than 500kHz. So, if your bitrate is 50kHz, then Fdev has to be less than 8200. (8200 x 64 = 524800. 524800 - (50000/2) = 499800Hz. 499.800kHz < 500kHz.)
The default value for Fdev is 5000. So you're good. No need to change it.

Then on page 64, for RegBitrateLsb if the Manshester encoding is enabled it says that BitRate = FXOSC / BitRate(15,0) Followed by Fdev = Fstep - Fdev(15,0) so its not (13,0) anymore ?

Fdev(15,0) is a typo. They mean (13,0). You probably want to enable man chester encoding. The man chester chip rate is essentially equal to bit rate. You might want to have a look at this:
https://www.maximintegrated.com/en/app- ... vp/id/3435

So All I want it to maximize the transfer rate to transmit either a config file or a audio file (needs 64kbps ideally but can be less) across in a short burst to then go back to default settings. I can set the radio to continuous mode if need be and turn off whitening for the audio transfer.

I think all you have to do is set the bit rate register.

[sid1202]

This is the part I'm get confused about. When reading up on the subject seams that changing the bit rate (reg 0x03 & 0x04) needs to be matched by changes to the bandwidth (0x19), the frequency deviation (0x05 & 0x06) and the Channel Filter BW control (0x1A). Also may be required to tweak the Packet mode settings (0x37) and the Data operation mode and Modulation settings (0x02)

Where did you see that? I'm not reading it that way. It looks to me like you simply change the bit rate.

From RadioHead forum, I asked "Is it as simple as setting the RegBitrateMsb and RegBitrateLsb ?"

And this is the answer I got: "Changing the bit rate involves changing a number of registers"

I think all you have to do is set the bit rate register.

Seems that I got overwhelmed by all this info and started to overthink this by quite a bit.

Thank you Rick for clearing things up. I can now move forward with my project :)

Sid

[adafruit_support_rick]

Well, I hope it works!

[sid1202]

I'll run a test routine this weekend. I'll pump out max length packets as fast as the feather can (32u4) and we'll see was happens. At least I don't have to worry so much about setting so many registers just to get started.

[sid1202]

I noticed that In the Adafruit example code the radio is always manually reset. I don't see that in other examples. Any particular reason for it ?

Sid

[adafruit_support_rick]

I don't think there's any reason other than good programming practice.