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Tracey is not using the RS-232
standard for either wiring or signal level. Signal is TTL, TX = pin 7, RX
= pin 27, and GND = pin 1
Joe
----- Original Message -----
Sent: Saturday, July 14, 2007 10:59
AM
Subject: [FlyRotary] Re: NOP was :
[FlyRotary] EM2 NOP flashing w/RPM and a couple of other questions
Just a little amplification to what Ed has said
-
I've worked with 3-wire RS232 for 27 years.- 8-N-1
(Xon/Xoff).
If Tracy is using the standard RS232 wiring
convention for the serial
connection, the TX is pin 2, RX is pin 3, but
signal ground is not pin 1,
it is pin 7 (DB25 connector) or pin 5 (DB9
connector). The ground on
pin 1 of the DB25 is "frame ground" and
"signal ground" is not
necessarily connected to it (indeed, it ~shouldn't~
be.)
Best Regards,
Dale R.
Ed Anderson wrote:
As best I recall, In the programming world, its a
mnemonic used to mean "No Operation"= NOP, in other words is was a line of
code that used up a clock cycle(s) of the chip but actually did
nothing. Sometimes used for timing purposes.
I think Tracy uses it to mean No
Operation. The link between the EC2 and the EM2 is via three
wires, two wires over which data and control pulses flow and the all
important ground wire. If do not have a good electrical ground between
your EM2 and EC2 the serial communication function will not operate properly
or may be sporadic. Since you have power to your EM2, I would check
and see that it has a good ground to the EC2.
Ed
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