connecting from usb to serial problem

Hi,
I have a ppc (405 ep) based chamelon dev kit. I wanted to re-use it
after long time ago. First i noticed that i do not have a serial
interface on my board, so i bought serial-to-usb connector, Then
noticed that the both side of serial-to-usb's and boards serial
connecter's output is male, i found a cable which has female
connectors on both sides. I connected my board and my pc via plugged-
in this long cable, i successfully receive messages from pretty old
board but then i noticed that i cannot type anything! actually i can
type but when pressed to a character, non-related and randomly some
weird character(s) appear, if i am lucky by pressing enter several
times to enter, i can send my command.
example output;

(I'm trying to type hello here)

CPU: IBM PowerPC 405EP Rev. B at 333.333 MHz (PLB=111, OPB=55,
EBC=37 MHz)
+----------------------------------------+
IIC Boot EEPROM disabled
PCI async ext clock used, internal PCI arbiter enabled
16 kB I-Cache 16 kB D-Cache
Board: ### No HW ID - assuming PPChameleonEVB
I2C: ready
DRAM: 32 MB
FLASH: 4 MB
PCI: Bus Dev VenId DevId Class Int
Video: Controller not found !
NAND: 32 MB
=> i i l M

i tried in both using minicom and cu and linux recognizes the
connector as /dev/ttyUSB0.My connection scheme

PPC rs232 male <--------rs232 female in bothe side -------><-----rs232
male to usb -------->Computers USB port

What can be a problem?

Thanks.

It sounds like a parameters problem - possibly speed, parity, or number of stop bits.

Might be a parameter problem but if you can see readable text from the board then the baud rate, parity and stop bits should be ok. Also might be a hardware/software control or a cable issue.

Hi actually beside hardware/software flow control, i tried everything including half/full duplex, im gonna try flow controls. There must be a trick, i tried different with usb to serial, it doesnt work too, even it works with serial to serial with same configuration.

USB to Serial adapters don't just work without drivers. The USB signals need to be translated or converted to serial and that is done with drivers.

I have never seen any USB to serial adapters with drivers for Linux.

Hardware handshaking *could* be another issue because some USB-serial converters only have Tx,Rx,GND and not anything else. However, the problem you describe is not typical of a hardware handshake issue (that doesn't mean it isn't, just that I'd look more carefully).

It's easy to test the 'hardware handshake' issue though - just set up the terminals so they don't use hardware handshakes.

Originally Posted by AuroraCA I have never seen any USB to serial adapters with drivers for Linux.

They've been around for years; the FTDI chipsets are probably the most common.

Pinniped

They've been around for years; the FTDI chipsets are probably the most common.

Interesting. You learn something every day. I've looked at about 20 different USB to Serial adapters and visited the manufacturer's websites and they only have drivers for various Windows versions.

Thanks

Originally Posted by AuroraCA I've looked at about 20 different USB to Serial adapters and visited the manufacturer's websites and they only have drivers for various Windows versions.

I don't know of any product which comes with a Linux driver on the disc, but many have a serial driver in the Linux kernel tree (usbserial). What is important is the VendorID:ProductID of the chipset. Numerous manufacturers use that FTDI chipset so many different brands and models in fact use the same driver.

Another important issue is the wiring of the RS232 side of the chip. If you need a USB serial converter you should check hardware compatibility sites and make sure that the device you plan to buy has all the signals you require; even if they have the same chipset, one manufacturer might only connect Tx,Rx,GND.

What serial port settings did you configure Minicom for when you used it ?

If you want a Terminal App that is GUI ... you can install PuTTY.

There is always the possibility that the cable is incorrectly wired, or that the board uses special pinouts.
Most DB9M RS-232 interfaces on PC's are DTE.
When connecting a DTE to another DTE interface a crossover cable must be used.


< For those that want to know: the native Linux kernel supports many different USB to Serial converters > I have used devices with FTDI and Prolific chipsets.

6510b proc # grep -i usb_serial /usr/src/linux/.config
CONFIG_USB_SERIAL=m
CONFIG_USB_SERIAL_GENERIC=y
# CONFIG_USB_SERIAL_AIRCABLE is not set
# CONFIG_USB_SERIAL_AIRPRIME is not set
# CONFIG_USB_SERIAL_ARK3116 is not set
# CONFIG_USB_SERIAL_BELKIN is not set
# CONFIG_USB_SERIAL_CH341 is not set
# CONFIG_USB_SERIAL_WHITEHEAT is not set
# CONFIG_USB_SERIAL_DIGI_ACCELEPORT is not set
# CONFIG_USB_SERIAL_CP2101 is not set
# CONFIG_USB_SERIAL_CYPRESS_M8 is not set
# CONFIG_USB_SERIAL_EMPEG is not set
CONFIG_USB_SERIAL_FTDI_SIO=m
# CONFIG_USB_SERIAL_FUNSOFT is not set
# CONFIG_USB_SERIAL_VISOR is not set
# CONFIG_USB_SERIAL_IPAQ is not set
# CONFIG_USB_SERIAL_IR is not set
# CONFIG_USB_SERIAL_EDGEPORT is not set
# CONFIG_USB_SERIAL_EDGEPORT_TI is not set
# CONFIG_USB_SERIAL_GARMIN is not set
# CONFIG_USB_SERIAL_IPW is not set
# CONFIG_USB_SERIAL_IUU is not set
# CONFIG_USB_SERIAL_KEYSPAN_PDA is not set
# CONFIG_USB_SERIAL_KEYSPAN is not set
# CONFIG_USB_SERIAL_KLSI is not set
# CONFIG_USB_SERIAL_KOBIL_SCT is not set
# CONFIG_USB_SERIAL_MCT_U232 is not set
# CONFIG_USB_SERIAL_MOS7720 is not set
# CONFIG_USB_SERIAL_MOS7840 is not set
# CONFIG_USB_SERIAL_NAVMAN is not set
CONFIG_USB_SERIAL_PL2303=m
# CONFIG_USB_SERIAL_OTI6858 is not set
# CONFIG_USB_SERIAL_HP4X is not set
# CONFIG_USB_SERIAL_SAFE is not set
# CONFIG_USB_SERIAL_SIERRAWIRELESS is not set
# CONFIG_USB_SERIAL_TI is not set
# CONFIG_USB_SERIAL_CYBERJACK is not set
# CONFIG_USB_SERIAL_XIRCOM is not set
# CONFIG_USB_SERIAL_OPTION is not set
# CONFIG_USB_SERIAL_OMNINET is not set
# CONFIG_USB_SERIAL_DEBUG is not set

A simple (though incomplete) test of the hardware is to loop the Tx pin back onto the Rx pin. In almost all cases, this will be a simple connection between pins 2 & 3. I prefer C-Kermit for working with serial ports, as it allows detailed configuration of the software and hardware. eg. set carrier-watch on/off, set flow-control none. Also, it is scriptable, and fairly well documented.
--- rod.