Back to "what fits in flash"

[lyzby]

I have a new application which requires only serial i/o, with a pl2303
or ftdi usb-to-serial adaptor. Can this be made to fit into flash,
and if so, how?

Or can on-board serial be adapted to utility use (at 2400 baud) with a
build which fits in flash?

Eagerly awaiting my new bifferboard.

[Andrew Scheller]

> I have a new application which requires only serial i/o, with a pl2303
> or ftdi usb-to-serial adaptor.  Can this be made to fit into flash,
> and if so, how?

Easily! You just need a usb-serial module (or compile it into the kernel).
A usb-serial module will take up much less much space than a
usb-webcam module :)

> Or can on-board serial be adapted to utility use (at 2400 baud) with a
> build which fits in flash?

Yup, but don't forget that the bifferboard's on-board serial port is
only TTL (i.e. 3.3V) levels, so you'll need an adaptor circuit to
connect it to a 'normal' serial port.
See this page for an example:
http://sites.google.com/site/bifferboard/Home/howto/use-bifferboard-as-serial-to-network-adapter

Lurch

[lyzby]

> See this page for an example:http://sites.google.com/site/bifferboard/Home/howto/use-bifferboard-a...
>
> Lurch

[lyzby]

Thanks for the reply. Level-shifting is no problem. Connection would
be to a 5V PICAXE microprocessor, so to my understanding, no level-
shifting would be needed on the biff-to-axe wire (with a 180 ohm
resistor for protection against miswiring), and a simple transistor
would work on the axe-to-biff wire. Your link shows how to detach the
onboard serial from linux. (Very nice link all-in-all, by the way).

I'm still uncertain, tho, as to how to make an in-flash build--what
instructions to follow. Has that been achieved in a user-friendly
fashion?

[biff...@yahoo.co.uk]

The Bifferboard IO is not 5v tolerant, or more specifically the
datasheet for the CPU makes no mention of it being, therefore, one
must assume it's not.

Connecting to 5v will be at your risk.

cheers,
Biff.

[Andrew Scheller]

> I'm still uncertain, tho, as to how to make an in-flash build--what
> instructions to follow. Has that been achieved in a user-friendly
> fashion?

I don't see why
http://sites.google.com/site/bifferboard/Home/howto/faster-route-to-kernel--initrd
wouldn't work?

You'd just need to enable your usb-to-serial adaptor in the kernel
config before making the kernel. (run 'make menuconfig' before running
'make')

Lurch

[lyzby]

Biff,

I didn't mean that 5 volts would get to the BB. My understanding is
that regarding the 3.3V serial output to the picaxe input, that input
will accept 3.3V as a 1 and 0V as a 0, and the BB will never see
anything but the 3.3V it is driving. On the input side with respect to
the BB, a transistor like the following would keep what the BB sees at
3.3V.

[IMG]http://i33.tinypic.com/2lu3xwg.gif[/IMG]

If that inserted image doesn't work, try this link:
http://tinypic.com/r/2lu3xwg/4

[biff...@yahoo.co.uk]

That should be fine. I've had HD44780 display working nicely with it
using just the 6 lines, and that was a 5-v device.