m5stack-cap-lora-1262listed

# M5Stack Cap LoRa-1262 (SKU U214) A snap-on **Cap** for the M5Stack Cardputer Adv (K132-Adv) and CardputerZero that adds two independent radios in one accessory: - **LoRa**: Semtech **SX1262** sub-GHz transceiver, 868–923 MHz, +22 dBm TX, −147 dBm RX (LDR mode), FSK/GFSK/MSK/GMSK/LoRa/OOK, external RP-SMA antenna (3 dBi, 108×9.3 mm, included). - **GNSS**: **ATGM336H-6N@AT6668** multi-constellation receiver (GPS/QZSS/ BeiDou-2/BeiDou-3/Galileo/GLONASS), 50 channels, up to 10 Hz update, <1.5 m CEP50, built-in ceramic patch antenna. UART interface, default 115200 baud, 8N1. Official docs: https://docs.m5stack.com/en/cap/Cap_LoRa-1262 Product page/SKU: https://docs.m5stack.com/en/products/sku/U214 ## Read this first — three things that will kill the cap or your bring-up 1. **Never power on without the LoRa antenna installed.** M5Stack's docs are explicit: "the device hardware may be permanently damaged." An SX1262 driving +22 dBm into no load reflects power back into its PA. This is not a warning that can be softened — the antenna is a prerequisite, not an accessory. 2. **The RF antenna switch is gated by an I/O expander pin, not by the SX1262 itself.** SDA/SCL on the cap connector go to a **PI4IOE5V6408** I/O expander whose **P0** must be driven high to enable the RF path. If your first `transmit()`/`receive()` calls do nothing (RadioLib returning no error but no packets on the air / no packets received), you almost certainly never enab