On 9/15/06, Dales, Michael W <michael.w.dales@...> wrote:
> Thanks for pointing out my mistake wrt to the robostix FFUART levels. I
> am using a USB->RS232 adaptor, but presumably one that can't cope with
> 5v. Interesting that it's logically inverted.
> I'm assuming that the tweener board is at 3.3v vanila RS232?
> The FFUART on the audiostix/gpsstix is stated as 3.3V - I assume this
> isn't inverted either?
RS232 levels are defined such that logic 0 is +3v to +15v and a logic
1 is -3v to -15v
Now many modern systems allow the -3v of a 1 to go all the way up to
ground. Some GPS units even advertise logic level RS232 which means a
0 is 5v and 1 is 0v (which is deceiving because you still need to
invert it to get logic level serial).
For logicl level serial, 0 is 0v and 1 is VCC (which for our purposes
is 3.3v for everything but the robositx, which is 5v).
The tweener and waysmall boards present RS232 levels, whereas all of
the breakout boards, audiostix, and robostx present logic level
A USB to RS232 converter is going to present RS232 level signals and
thus is only compatible with the tweener/wyasmall boards. For all of
the logic level outputs, you would need a serial adapter which
converts logic level serial to RS232 level serial.
Vancouver, BC, Canada