When is buffer free during interrupt driven transmission ? (SX1262)

[MrSniffer]

If I move data into a buffer, and then do an interrupt driven transmission, e.g.

int16_t startTransmit(uint8_t* buffer, .... );

when the call to startTransmit returns: is the buffer free to be refilled, or must I wait for the transmit complete interrupt? I would like to refill the buffer while the SX1262 is sending out the previous packet. Or is the SX1262 sending it out from my userspace buffer?

[jgromes]

startTransmit(uint8_t* does not copy your buffer in the MCU, it sends out its contents to the radio. That's all being done in startTransmit which ends when the buffer has been sent and transmission begins. So you can modify the buffer during an ongoing transmission but only after startTransmit returns.

[HeadBoffin]

Consider if you need to fill the buffer that quickly, you are very likely breaching local legal laws regarding duty cycle - typically 1% maximum airtime. And if you are doing back to back transmissions on the same frequency, sooner or later it will look like a denial of service to other users ...