UARTs

Logic level (3.3V) signals
FFUART speeds to 230 kbps (normally mapped to ttyS0 in the kernel and Y0 in some schematics )
HWUART speeds to 921 kbps (normally mapped to ttyS3 in the kernel and Y1 in some schematics)
Both can use RxD, TxD, RTS, CTS.
STUART speeds to 230 kbps (normally mapped to ttyS2)
BTUART is not an exposed interface; mapped to ttyS1 by the kernel and connected physically to the bluetooth module if one is present.

Note! Current kernels use ttyS3 (HWUART) for bluetooth. This is available on the BTUART pins by setting GPIO42 and 43 to AF3 - and this is the default configuration. This can be very confusing if you want to use the HWUART for something else! To re-enable HWUART on ttyS3, make bluetooth use ttyS1 (see /etc/default/bluetooth) and then set GPIO42 to AF1 in and GPIO43 to AF2 out. You can then set GPIO48 to AF1 out (HWUART TXD) and GPIO49 to AF1 in (HWUART RXD).

FF_CTS

FF_RTS

FF_TXD

FF_RXD

HW_CTS

HW_RTS

HW_TXD

HW_RXD

BT_CTS

BT_RTS

BT_TXD

BT_RXD

BT_NRESET

BTUART pins are located on the 60-pin Hirose and 24-pin flex ribbon (Verdex only) connectors.
It is not an exposed interface; mapped to ttyS1 by the kernel and connected physically to the bluetooth module if one is present.

Related pages on the old wiki:

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