Difference between revisions of "Add a Serial port to the LS DUO"

Revision as of 04:54, 8 September 2008

This information comes from this forum thread^[1]

Serial Port Pinout

The connector for the Serial port is CN10 it is easy to make out from the frontside image where GND is.

Frontside and Backside Images

The pinout (if you look on the board from the frontside): [RxD]-[TxD]-[Vcc]-[GND]

The pinout (if you look on the board from the backside): [GND]-[Vcc]-[TxD]-[RxD]

Use a Level Shifter

The serial port signals from the processor are only 3.3V. For proper RS-232 12V signaling, an RS-232 level shifter needs to be added. These are very common in PDA serial cables also, but can be purchased

Models other than KuroPro

If you are attaching a serial header pin onto the main board, you may want to consider: Using the header pin unit with a 90 degree bend, or you might not be able to close the case Soldering it with the pins toward the interior, rather than toward the case. This allows easier access, since if the pins face the case side they would be very close to the metal side. This would make access is so tight that one might end up taking the board out to get plug fitted on the pins.

Build your own LVTTL/RS232 or LVTTL/USB interface

• LVTTL/RS232 - Building a Custom Serial Interface
• LVTTL/USB - Use a Nokia Serial Cable on an ARM9 Linkstation
• LVTTL/USB - Use a cheap phone sync cable with the serial port

Buy your own TTL Level Shifter

• LVTTL/RS232 - MAX232 based from Futurelec - MINIRS2323V
• LVTTL/USB - FTDI chip based cable - TTL-232R-3V3

Usage considerations for the TTL-232R-3V3

TTL-232R-3V3 USB to TTL Serial Converter Cable A very similar TTL/USB converter cable that uses a chip by FTDI (the same chip is used in the SCON-KIT ) can be obtained, but the pinout at the connector end would need to be reassigned: Spec Sheet w/ pinout, wire colors & other info Mouser Part # 895-TTL-232R-3V3 $20.00 Mouser Part # 517-929400-01-04 $0.32

A working/tested pinout/wire-color scheme is: Color Pin Number Signal yellow 1 TXD orange 2 RXD unused 3 VCC black 4 GND

• Solder the 4-pin header to the board. Make sure you don't have shorts.
• You will need to switch wires on the TTL-232R-3V3 cable. Use a sharp object to lift the plastic tabs and carefully pull the wires out. Rearrange them according to the table above (black, empty, orange, yellow, empty, empty) and slide those wires back in. Tape the other wires to make sure they don't short anything.
• When plugging in the cable, make sure black aligns with GND, yellow with TXD, and orange with RXD.
• Connect the USB cable to your computer, start a terminal program with the right settings.
• Turn on the device, you should see output from the bootloader in couple seconds.

References

1. ↑ The Buffalo NAS hacking Forums:Serial @ Pro Duo