What's this macro doing?

[mcauser]

Inside /arduino/nRF905/nRF905.cpp, line 75.

Can you please explain what these lines are used for?

#define STANDBY (enableStandbyMode())
#define CHIPSELECT(standby) standby; \
							for(bool cs = cselect(); cs; cs = cdeselect())

Is the CHIPSELECT macro an optimised way of wrapping a block of code with cselect() + cdeselect() and optionally calling enableStandbyMode() first?

eg.

CHIPSELECT(STANDBY)
{
	spi_transfer_nr(NRF905_CMD_W_CONFIG | NRF905_REG_CHANNEL);
	spi_transfer_nr(channel);
	spi_transfer_nr(config.reg1);
}

I noticed the pattern is repeated in the NRF905_ATOMIC macro:

#define NRF905_ATOMIC() for(bool cs = interrupt_off(); cs; cs = interrupt_on())

[ZakKemble]

You've hit the nail on the head on what the macro does :P
The end compiled code is the same as if cselect() and cdeselect() were used directly. I use the macro as I find it a little bit neater, really. I first came across the idea when looking at how AVR-LIBC did the ATOMIC_BLOCK stuff http://www.nongnu.org/avr-libc/user-manual/atomic_8h_source.html
You can also exit the block early with a 'continue;' and cdeselect() will still be called (I can't remember what happens with a return or break).

CHIPSELECT can be used inside an ISR or if you use the STANDBY option you can use it outside an ISR.
If a section of code should not be interrupted by the ISR (like coping buffers) then it should be wrapped with NRF905_ATOMIC.

[mcauser]

Nice work! I'm porting your library to MicroPython so I can mix Arduino nodes with pyboard (STM32) and ESP8266 nodes.
Will share the GitHub link once it's ready.