fix #913

[2bndy5]

Essentially, this reverts the algorithm used to satisfy #650 as it has proved erroneous.

[github-actions]

Memory usage change @ 6db47d6

Board	flash	%	RAM for global variables	%
ATTinyCore:avr:attinyx5	🔺 0 - +46	0.0 - +0.56	0 - 0	0.0 - 0.0
arduino:avr:nano	❔ -12 - +42	-0.04 - +0.14	0 - 0	0.0 - 0.0
arduino:samd:mkrzero	🔺 0 - +56	0.0 - +0.02	0 - 0	0.0 - 0.0

Click for full report table

Board	examples/rf24_ATTiny/rf24ping85 flash	%	examples/rf24_ATTiny/rf24ping85 RAM for global variables	%	examples/rf24_ATTiny/timingSearch3pin flash	%	examples/rf24_ATTiny/timingSearch3pin RAM for global variables	%	examples/GettingStarted flash	%	examples/GettingStarted RAM for global variables	%	examples/AcknowledgementPayloads flash	%	examples/AcknowledgementPayloads RAM for global variables	%	examples/ManualAcknowledgements flash	%	examples/ManualAcknowledgements RAM for global variables	%	examples/StreamingData flash	%	examples/StreamingData RAM for global variables	%	examples/MulticeiverDemo flash	%	examples/MulticeiverDemo RAM for global variables	%	examples/InterruptConfigure flash	%	examples/InterruptConfigure RAM for global variables	%	examples/scanner flash	%	examples/scanner RAM for global variables	%	examples/encodeRadioDetails flash	%	examples/encodeRadioDetails RAM for global variables	%
ATTinyCore:avr:attinyx5	46	0.56	0	0.0	0	0.0	0	0.0
arduino:avr:nano									20	0.07	0	0.0	30	0.1	0	0.0	18	0.06	0	0.0	-12	-0.04	0	0.0	16	0.05	0	0.0	42	0.14	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0
arduino:samd:mkrzero									52	0.02	0	0.0	56	0.02	0	0.0	52	0.02	0	0.0	52	0.02	0	0.0	56	0.02	0	0.0	52	0.02	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0

Click for full report CSV

Board,examples/rf24_ATTiny/rf24ping85<br>flash,%,examples/rf24_ATTiny/rf24ping85<br>RAM for global variables,%,examples/rf24_ATTiny/timingSearch3pin<br>flash,%,examples/rf24_ATTiny/timingSearch3pin<br>RAM for global variables,%,examples/GettingStarted<br>flash,%,examples/GettingStarted<br>RAM for global variables,%,examples/AcknowledgementPayloads<br>flash,%,examples/AcknowledgementPayloads<br>RAM for global variables,%,examples/ManualAcknowledgements<br>flash,%,examples/ManualAcknowledgements<br>RAM for global variables,%,examples/StreamingData<br>flash,%,examples/StreamingData<br>RAM for global variables,%,examples/MulticeiverDemo<br>flash,%,examples/MulticeiverDemo<br>RAM for global variables,%,examples/InterruptConfigure<br>flash,%,examples/InterruptConfigure<br>RAM for global variables,%,examples/scanner<br>flash,%,examples/scanner<br>RAM for global variables,%,examples/encodeRadioDetails<br>flash,%,examples/encodeRadioDetails<br>RAM for global variables,%
ATTinyCore:avr:attinyx5,46,0.56,0,0.0,0,0.0,0,0.0
arduino:avr:nano,,,,,,,,,20,0.07,0,0.0,30,0.1,0,0.0,18,0.06,0,0.0,-12,-0.04,0,0.0,16,0.05,0,0.0,42,0.14,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0
arduino:samd:mkrzero,,,,,,,,,52,0.02,0,0.0,56,0.02,0,0.0,52,0.02,0,0.0,52,0.02,0,0.0,56,0.02,0,0.0,52,0.02,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0

[github-actions]

Memory usage change @ 2e1d682

Board	flash	%	RAM for global variables	%
ATTinyCore:avr:attinyx5	🔺 0 - +46	0.0 - +0.56	0 - 0	0.0 - 0.0
arduino:avr:nano	❔ -12 - +42	-0.04 - +0.14	0 - 0	0.0 - 0.0
arduino:samd:mkrzero	🔺 0 - +16	0.0 - +0.01	0 - 0	0.0 - 0.0

Click for full report table

Board	examples/rf24_ATTiny/rf24ping85 flash	%	examples/rf24_ATTiny/rf24ping85 RAM for global variables	%	examples/rf24_ATTiny/timingSearch3pin flash	%	examples/rf24_ATTiny/timingSearch3pin RAM for global variables	%	examples/GettingStarted flash	%	examples/GettingStarted RAM for global variables	%	examples/AcknowledgementPayloads flash	%	examples/AcknowledgementPayloads RAM for global variables	%	examples/ManualAcknowledgements flash	%	examples/ManualAcknowledgements RAM for global variables	%	examples/StreamingData flash	%	examples/StreamingData RAM for global variables	%	examples/MulticeiverDemo flash	%	examples/MulticeiverDemo RAM for global variables	%	examples/InterruptConfigure flash	%	examples/InterruptConfigure RAM for global variables	%	examples/scanner flash	%	examples/scanner RAM for global variables	%	examples/encodeRadioDetails flash	%	examples/encodeRadioDetails RAM for global variables	%
ATTinyCore:avr:attinyx5	46	0.56	0	0.0	0	0.0	0	0.0
arduino:avr:nano									20	0.07	0	0.0	30	0.1	0	0.0	18	0.06	0	0.0	-12	-0.04	0	0.0	16	0.05	0	0.0	42	0.14	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0
arduino:samd:mkrzero									16	0.01	0	0.0	16	0.01	0	0.0	16	0.01	0	0.0	16	0.01	0	0.0	16	0.01	0	0.0	16	0.01	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0

Click for full report CSV

Board,examples/rf24_ATTiny/rf24ping85<br>flash,%,examples/rf24_ATTiny/rf24ping85<br>RAM for global variables,%,examples/rf24_ATTiny/timingSearch3pin<br>flash,%,examples/rf24_ATTiny/timingSearch3pin<br>RAM for global variables,%,examples/GettingStarted<br>flash,%,examples/GettingStarted<br>RAM for global variables,%,examples/AcknowledgementPayloads<br>flash,%,examples/AcknowledgementPayloads<br>RAM for global variables,%,examples/ManualAcknowledgements<br>flash,%,examples/ManualAcknowledgements<br>RAM for global variables,%,examples/StreamingData<br>flash,%,examples/StreamingData<br>RAM for global variables,%,examples/MulticeiverDemo<br>flash,%,examples/MulticeiverDemo<br>RAM for global variables,%,examples/InterruptConfigure<br>flash,%,examples/InterruptConfigure<br>RAM for global variables,%,examples/scanner<br>flash,%,examples/scanner<br>RAM for global variables,%,examples/encodeRadioDetails<br>flash,%,examples/encodeRadioDetails<br>RAM for global variables,%
ATTinyCore:avr:attinyx5,46,0.56,0,0.0,0,0.0,0,0.0
arduino:avr:nano,,,,,,,,,20,0.07,0,0.0,30,0.1,0,0.0,18,0.06,0,0.0,-12,-0.04,0,0.0,16,0.05,0,0.0,42,0.14,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0
arduino:samd:mkrzero,,,,,,,,,16,0.01,0,0.0,16,0.01,0,0.0,16,0.01,0,0.0,16,0.01,0,0.0,16,0.01,0,0.0,16,0.01,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0

[TMRh20]

My testing indicates this is an issue on all boards. It doesn't seem to matter the speed, anytime the radio receives a packet and the IRQ is raised, could be at the same time the MCU is polling for available();. This fix seems to work on all devices as well, from RPi to AVR devices.

[2bndy5]

Updated OP. Thanks for testing this, I was having trouble reproducing this.

[2bndy5]

I am [optimistically] curious how this will effect the promiscuous scanner branch's mods...

[TMRh20]

I am getting similar results to the original with the promiscuous scanner branch testing with Due and Nano, so at least there are no problems with it.

[2bndy5]

I rebased the promiscious-scanners branch on master. My hope is that the "slower" available() will be better with the SPIDEV driver.

[2bndy5]

Should we publish a release with this fix for Arduino?

I'm thinking the slower available() will allow for timely reception of network messages during network.update()'s while (radio.available()) loop. 🤷🏼‍♂️

[TMRh20]

Yeah maybe, we aren't likely to have too many upcoming changes to RF24 and its probably best to get it in there.

[2bndy5]

ATTinyCore is failing to install in CI. I'm not entirely sure why though. It shouldn't prevent releases from completing, however the badge in README will display red.

[2bndy5]

Update: I was able to fix the ATTinyCore install problem in CI on advice from SpenceKonde. Turns out that the Arduino CLI tool had some kind of breaking change after v0.33.0 which can only be observed from Github Action runners. Thus our CI is pinned to using Arduino CLI v0.33.0 (in the reusable workflow: nRF24/.github@6e04aae).

[2bndy5]

Another update on ATTinyCore install in CI:

arduino/arduino-cli#2345 tracks the problem reported. The fix is merged, so now I'm just posting a reminder to update the reusable workflow when the new Arduino CLI version is released.