I’m using the RADIO peripheral for BLE 1M connection-event RX→TX turnaround.
Current flow:
1. RADIO receives a data PDU.
2. RADIO reaches END/PHYEND and disables.
3. In the RADIO ISR, firmware parses the received packet.
4. Firmware selects/builds the response packet and updates PACKETPTR.
5. Firmware starts TX.
I want to use RADIO.TIFS = 150 us for BLE inter-frame spacing.
Question:
For hardware TIFS to work on RX→TX turnaround, must PACKETPTR for the TX packet already be valid before the received packet reaches END/PHYEND / before DISABLED occurs?
Or is it valid to update PACKETPTR during the 150 us TIFS interval, then trigger TXEN or use DISABLED_TXEN, with the hardware still enforcing TIFS?
In other words, does RADIO.TIFS apply only to the DISABLED→TXEN/RXEN shortcut sequence armed before DISABLED, or can firmware prepare the TX packet after RX completion and still rely on TIFS timing?
In my dynamic case, the response packet is not known until after the RX packet is inspected in the ISR, but the TX PACKETPTR can be ready well before 150 us expires.