Datasheet

Can I use the IRQ pin to wake my MCU up from sleep when BLE UART data is available?
No, on SPI-based boards the IRQ pin is used to indicate that an SDEP response is available to an SDEP command. For example, when you sent
the `AT+BLEUARTRX` command as an SDEP message, the Bluefruit firmware running on the nRF51822 will parse the message, prepare an
SDEP response, and trigger the IRQ pin to tell the MCU that the response is ready. This is completely independant from the BLE UART service,
which doesn't have interrupt capability at present.
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