UARTs

• 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).

 

FFUART

 

FF_CTS

FF_RTS

FF_TXD

FF_RXD

 

• Logic level (3.3V) signals
• Speeds to 230 kbps
• Normally mapped to ttyS0 in the kernel and Y0 in some schematics
• FFUART pins are located on the 60-pin Hirose connector
• Schematic diagram for the FFUART

HWUART

 

HW_CTS

HW_RTS

HW_TXD

HW_RXD

 

• Logic level (3.3V) signals
• Speeds to 921 kbps
• Normally mapped to ttyS3 in the kernel and Y1 in some schematics
• HWUART pins are located on the 60-pin Hirose (Connex and Basix only)
• Schematic diagram for the HWUART

STUART

 

• Logic level (3.3V) signals
• Speeds to 230 kbps
• Normally mapped to ttyS2
• Schematic diagram for the STUART

BTUART

 

BT_CTS

BT_RTS

BT_TXD

BT_RXD

 

BT_NRESET	Bluetooth reset (output, active low)
CLK_32	32.768 kHz Clock output

 

• Logic level (3.3V) signals
• 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.
• BT_NRESET and CLK_32 are for an optional Bluetooth module IC (24-pin flex ribbon only)