Any reason RFM69HW cannot substitute for RFM69W?

Started by Zeph, April 27, 2014, 07:19:30 PM

Zeph

As best I can tell so far, a Motino with RFM69HW can do everything the RFM69W does, and probably has about the same power usage if you do not enable the higher power modes.  So the extra cost would be the only downside of using the HW.

Right?

Or is there something I'm missing?

Felix

"Extra cost" ...  haha ;D
It's like when you want to buy a regular Audi and a turbo charged one. Both look the same, smell the same, drive the same, but the turbo gives you extra adrenaline. That's why you pay "extra" for it ;)

Zeph

The "extra cost" is just $1/module or moteino, very modest

I'm asking if there is any downside to using the 69HW vs 69W, other than that buck.  To use your analogy, does the turbo model lack any feature, or get worse gas milage even if you don't turn on the turbo?

Sometimes that happens with chips - in choosing the version with some desirable trait, you have tradeoffs in some other area - voltage range, min power, some feature.  I'm guessing that's not the case with the RFM69W vs HW tho.  If you don't turn on the Turbo, it works EXACTLY like the base model.

Felix

Well several threads in the forum discuss some of the differences. Mainly the HW uses a different amplifier output, which gives you the extra 7dBm of gain. So that will eat a lot more power. Physically there's a bunch more circuitry on the HW.
You can turn power down on either W or HW but I'm not sure it makes a lot of sense to use the HW at W capacity.

Zeph

For anyone who encounters this thread, see the thread https://lowpowerlab.com/forum/index.php/topic,362.0.html

It turns out that the 69HW doesn't simply scale back to 69W power ranges.

Unless John finds a way to disable RXTX, and the library remaps desired power levels to multiple register settings...