UsbToFbus

USB => RS232 (-/8V serial) and USB => FBUS (3V serial) solutions

Most notebooks don't have embedded RS232 port now. So USB to RS232 adapter is necessary.


Types of USB => serial cables

PL2303 is the most common. NEVER USE THE DRIVER CD from the USB-RS232 adapter box. (only as a last chance after you tried everything else without luck, but that should never happen). See ProlificWindowsDriver

[PL2303 datasheet]

  • linux module name is pl2303
  • [OLD driver] (md5sum checksum /cdrom/PL-2303X/Setup.exe = bb01cb5bd5d139cea620ad4e4276fffd )

Besides the common pl2303 and cypress_m8, FTDI, etc..., there are about 20 drivers in linux 2.6 for similar purpose (usbserial) so there are many others too. We don't have information on which one supports 16 bit words (all supports 8 bit words, pf course), that would be useful to boot OtherTuningSoftware/NintendoGameBoy from PC (for running program, eg. for reflashing GBA flash).

Some (like the cypress) contain general purpose microcontroller with OTP or rewritable flash that could theoretically be tweaked to support anything.


Samples under evaluation

I just received some reasonably priced USB => mobile-phone cables so we can sample, if it can be used for GenBoard/CommToPC (and finally stock in the WebShop if useful).

Some are not useful:

(I only had time to look into it after ordering some "blindly")

But this one looked promising and looks like a real winner now:


Yes, the Nokia1100 maintenance cable will be our best friend

Look what the chip says (standard lsusb command on linux):

# lsusb
Bus 001 Device 004: ID 067b:2303 Prolific Technology, Inc. PL2303 Serial Port

This means that it has the (most common) PL2303 chip inside.


Use under Linux - takes just 2 lines

There is standard driver in linux and for win32 that drives this, so it shows up as a standard serial port:

# modprobe pl2303
you will see in the syslog (dmesg, or less /var/log/syslog):
... kernel: pl2303 1-2:1.0: PL-2303 converter detected
... kernel: usb 1-2: PL-2303 converter now attached to ttyUSB0
you just make the devices:
# cd /dev
# mknod ttyUSB0 c 188 0
and if you plug in more similar devices, just continue to add ports:
# mknod ttyUSB1 c 188 1

It's that simple (effectively 2 lines to paste!!!).


Use under windows - it's a bit harder but still simple.

In winblows it's more work, install a(n available for download) driver and reboot (and also pray, as there is less indication of what's going on - as usual for winblows). Fortunately it's working OK in win too, as long as I don't use the parallel port at the same time - together they often bluescreen, but I should update to a new PL2303 driver to see if it's fixed - admittedly I have an old version. Also it becomes COM5, and many windows programs are too lame: you can only choose COM1..4 (rarely just COM1..2).


Notes:


Pinout

I don't have a nokia1100 phone, so the phone orientation might be wrong (unlikely though). Here it is drawn as if the phone was transparent (looking onto the connector, the pins pointing out of the screen).

+.............................................

| | |

|... NC .. Green

|White Blue

+.............................................

The connector ends here ^ the rest is just phone :-)

wire color function
green GND
blue data to the Phone - AVR RX
white data from the Phone - AVR TX
NC not connected

Links:


TODO


Real test of the nokia1100 cable

Before buying up the world stock of leftover Nokia1100 cable, I wanted to be sure that it works for us.

If devlopers wants to experiment with it (and report!) please ask in WebShop.


small max232 board design dropped - we don't need to design the max232 board into the DB9 housing since we have both RS232=>FBUS and USB=>FBUS (also USB => RS232) in stock (off-the-shelf price is similar to what it would cost to manufacture: DB9 + max232 chip + PCB + PNP soldering + cables + assembly + testing).

However a small board that has CAN transceiver that attaches to FBUS would be nice.


See also