Author Topic: RFM69HCW current usage in high power mode  (Read 2943 times)

perky

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Re: RFM69HCW current usage in high power mode
« Reply #15 on: March 02, 2018, 09:04:11 AM »
HW does not have 32 states of power, only half, that is why you have /=2
The sx1231h datasheet actually states it's the upper values 16-31 of PAlevel that are used, technically the lower values 0-15 are undefined. Dividing by 2 forces the values to 0-15. Those values seem to work to a degree, but close examination of the current consumption in the link I gave above seems to show 80mA at a value of 15 and 110mA at a value of 31 (for PA1+PA2+HP), so I'm not convinced using 0-15 is the same as 16-31. Interestingly Radiohead uses 16-31.

Mark.

TomWS

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Re: RFM69HCW current usage in high power mode
« Reply #16 on: March 02, 2018, 10:07:59 AM »
The sx1231h datasheet actually states it's the upper values 16-31 of PAlevel that are used, technically the lower values 0-15 are undefined. Dividing by 2 forces the values to 0-15. Those values seem to work to a degree, but close examination of the current consumption in the link I gave above seems to show 80mA at a value of 15 and 110mA at a value of 31 (for PA1+PA2+HP), so I'm not convinced using 0-15 is the same as 16-31. Interestingly Radiohead uses 16-31.

Mark.
Good point.  I found that there is also a difference in output when a single PA is used, ie PA1 != PA2.  Unfortunately I don't remember which one to use if you're using a single (PA2, I think), I'd have to look at my old ATC code to confirm.

Tom

ChemE

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Re: RFM69HCW current usage in high power mode
« Reply #17 on: March 02, 2018, 10:22:19 AM »
This is one of the better write ups I've found over the years on the subject: http://www.electrobob.com/rfm69-output-power/

perky

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Re: RFM69HCW current usage in high power mode
« Reply #18 on: March 02, 2018, 10:57:06 AM »
This is one of the better write ups I've found over the years on the subject: http://www.electrobob.com/rfm69-output-power/
This firmware 'fix' is in the Radiohead library now.

brolly759

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Re: RFM69HCW current usage in high power mode
« Reply #19 on: March 02, 2018, 04:25:30 PM »