pin active function note
CLK 3-wire SPI
MISO 3-wire SPI
MOSI 3-wire SPI
CS low 4-wire SPI

For the SX1262, the NSS pin (chip select) is active low TTL.

Meaning:

  • Idle (not selected): NSS = HIGH
  • Active (selected): NSS = LOW
  • Level logic: 3.3 V high, 0 V low (since SX1262 is a 3.3 V device — do not feed it 5 V).

From Semtech SX1262 datasheet:

  • NSS is internally pulled high by default.
  • Every SPI transaction starts when NSS goes low and ends when NSS goes high.
  • All SPI data must be clocked while NSS is low.

ref