UARTs
From Gumstix User Wiki
Contents
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)
Related pages on the old wiki:
http://docwiki.gumstix.org/index.php/Gumstix_UARTs
http://docwiki.gumstix.org/index.php/Gumstix_motherboard_I/O#UART
http://docwiki.gumstix.org/index.php/Tips_and_tricks#UARTs
.
