----- Original Message -----
Sent: Monday, May 06, 2002 3:02 PM
Subject: Port #2 Pinout
Hello, anybody:
I am retrofiting a Enco Mill/Drill with steppers
and EMC. I was looking at the bridgeportio.ini and I realeazed the
following:
A) I can use Port #2 to for coolant and spindle
actuations and such.
B) The "numbers" assigned to different functions
in the ini file under port #2 are D0, D1, D2..repectively. They are not pin
numbers.
C) I can look at a standard 25 pin schematic and
some of the data port pins decribed in bridgeportio.ini are treated as
outputs...and the output section of a par. port has only 8 data out bits....so
EMC is using more than 8 data out bits? Huh?
Item C confuses me assuming that I got item B
correct.
If I blew it, would somebody please send me or
direct me to the correct pinouts for the bridgeport io? And if I just stubbed
my toe, please educate me.
Thanks in advance,
Since I didn;t See another reply I'll give it a
shot, even though I have no direct experience and have not looked
at the file in question.
(C) Has an assumption that is not correct, there
ARE more that 8 outputs on a standard IBM printer port.
For Starters Look at the way a regular printer
works.
First The Data is set on data lines 0-7, THEN The
(Strobe line) is pulled LOW Then Back High.
This step is what latches the data into the
printer itself.
Those -3- things need to be done by SOFTWARE for
each character printed.
IF you decide to follow another handshaking
protocol things can work differently.
Right there we are using 9 outputs, there are 12
by default.
Be aware the <Other> 4 outputs are almost
always "Open Collector" and are not
"Driven" to a high 5V As such you need to add a
"Pull-up".
The simple description is that it's like a bucket
with a valve,
"Full of water" is ON and Empty is OFF.
With "Open Collector" the only thing you control
is the valve, the "Pull-Up" is
like a hose running water into the bucket ALL the
time.
The "Flow" needs to be sized to allow the "Open"
valve to empty and keep the
bucket empty when open but allow a quick
refilling when the valve is shut.
Another common problem is reverse logic used by
some of the pins.
Sometimes the logic is reserved so that
"Asserted" is a low voltage
and "Negated" is high.
The logic states of some of the pins are like
this and you need to remember that
in your code or hardware connections. In other
words sometimes you need to Write
a "1" to get a low voltage or a "0" to get a High
instead of what you'd assume.
There are several parallel port FAQs on the
web.
<<QUOTE>>
Pin signals and register bits
<= in
DB25 Cent Name
of Reg
=> out
pin pin
Signal
Bit Function Notes
------
---- ----
-------- ---
-----------------------------
=>
1 1
-Strobe
C0- Set Low pulse >0.5 us to
send
=>
2 2 Data
0
D0 Set to least significant
data
=>
3 3 Data
1
D1
...
=>
4 4 Data
2
D2
...
=>
5 5 Data
3
D3
...
=>
6 6 Data
4
D4
...
=>
7 7 Data
5
D5
...
=>
8 8 Data
6
D6
...
=>
9 9 Data
7
D7 Set to most significant
data
<= 10
10
-Ack S6+ IRQ
Low Pulse ~ 5 uS, after accept
<=
11 11
+Busy
S7- High for
Busy/Offline/Error
<=
12 12
+PaperEnd S5+ High
for out of paper
<=
13 13
+SelectIn S4+ High
for printer selected
=>
14 14
-AutoFd
C1- Set Low to autofeed one
line
<= 15
32
-Error
S3+ Low for
Error/Offline/PaperEnd
=>
16 31
-Init
C2+ Set Low pulse > 50uS to
init
=> 17
36
-Select
C3- Set Low to select
printer
== 18-25 19-30,
Ground
33,17,16
Marc
Christensen