USB to serial adapter
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This type of adapter allows you to add several serial (RS232) ports to your APF board, through the USB Host interface (only available on DevFull & APF27)
Tested materials
 |
Warning: Due to some bugs in the (uggly) ISP1761 driver, USB to serial adapters are currently not usable on the APF9328 ! |
The commercial adapters can be separated in 2 categories, because there are only 2 USB<->serial low cost chipmakers:
- FTDI one
- Prolific one (pl23xx)
| Adapter Model | Chip | Status APF9328 / APF27 |
Driver | Comments | |
|---|---|---|---|---|---|
| Trendnet TU-S9 | pl2303 | pl2303 | |||
| XXXX | |||||
Installation
$ make linux26-menuconfig
Device Drivers --->
[*] USB support --->
...
*** USB port drivers ***
<M> USB Serial Converter support
...
<M> USB FTDI Single Port Serial Driver
<M> USB Prolific 2303 Single Port Serial Driver
$ make linux26 && make
copy following drivers on your target or reflash your rootfs (for more infos, see this page)
drivers/usb/serial/ftdi_sio.ko drivers/usb/serial/pl2303.ko drivers/usb/serial/usbserial.ko
Usage
- be sure that your USB Host is running on your board: explanations are here
- plug your USB adapter (here a Prolific one)
usb 1-1: full speed USB device using mxc-ehci and address 2 usb 1-1: configuration #1 chosen from 1 choice usb 1-1: New USB device found, idVendor=067b, idProduct=2303 usb 1-1: New USB device strings: Mfr=1, Product=2, SerialNumber=0 usb 1-1: Product: USB-Serial Controller D usb 1-1: Manufacturer: Prolific Technology Inc.
- Load the module, for example if you have a Prolific based adapter:
# modprobe pl2303 usbcore: registered new interface driver usbserial usbserial: USB Serial Driver core usbserial: USB Serial support registered for pl2303 pl2303 1-1.1:1.0: pl2303 converter detected usb 1-1.1: pl2303 converter now attached to ttyUSB0 usbcore: registered new interface driver pl2303 pl2303: Prolific PL2303 USB to serial adaptor driver #
- a new serial device will then appear under /dev/ttyUSBN (N starting at 0 and depending on the number of adapters detected).
 |
Note: You can use now this new device like a standard Linux serial port |
Troubelshooting
- If your USB <-> Serial converter doesn't seem to work, run the dmesg command. You should read this thread if you see some disconnection data like this :
[ 2445.568000] usb 1-1.4: new full speed USB device using uhci_hcd and address 22 ... [ 2446.964000] ftdi_sio ttyUSB0: FTDI USB Serial Device converter now disconnected from ttyUSB0 [ 2446.964000] ftdi_sio 1-1.4:1.0: device disconnected
