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Parallel Port I/O as used by EMC

The IBM-PC's Parallel Printer Port has a total of 12 digital outputs and 5 digital inputs accessed via 3 consecutive 8-bit ports in the processor's I/O space. 8 output pins accessed via the DATA Port 5 input pins (one inverted, indicated by line over number) accessed via the STATUS Port 4 output pins (three inverted, indicated by line over number) accessed via the CONTROL Port The remaining 8 pins are grounded

EMC First Parallel Port Map [motion]

DB25 Pin	Signal/Dir	EMC Signal Using Step/Dir	EMC Signal Using Phase Drive	Using Six Axis Hexapod
1	/c0 - Out	n/a	n/a	Motor-4 DIR
2	d0 - Out	x dir HOMING_POLARITY = 1	motor-0 phase-A	Motor-0 DIR
3	d1 - Out	x step	motor-0 phase-B	Motor-0 STEP
4	d2 - Out	y dir HOMING_POLARITY = 1	motor-1 phase-A	Motor-1 DIR
5	d3 - Out	y step	motor-1 phase-B	Motor-1 STEP
6	d4 - Out	z dir HOMING_POLARITY = 1	motor-2 phase-A	Motor-2 DIR
7	d5 - Out	z step	motor-2 phase-B	Motor-2 STEP
8	d6 - Out	n/a	??	Motor-3 DIR
9	d7 - Out	n/a	??	Motor-3 STEP
10	s6 - In	OPTION PROBE PROBE_POLARITY = 1	??	unused
11	/s7 - In	OPTION PROBE PROBE_POLARITY = 0	??	unused
12	s5 - In	x,y,z home HOME_SWITCH_POLARITY = 1	??	All motors Reference Sw
13	s4 - In	x,y,z limit- MIN_LIMIT_SWITCH_POLARITY = 1	??	All motors Neg Limit Sw
14	c1 - Out	n/a	n/a	Motor-4 STEP
15	s3 - In	x,y,z limit+ MAX_LIMIT_SWITCH_POLARITY = 1	same	All Motors Pos Limit Sw
16	c2 - Out	n/a	n/a	Motor-5 DIR
17	/c3 - Out	n/a	n/a	Motor-5 STEP
18-25	ground	n/a	n/a	Ground

Notes on probing

[TRAJ] PROBE_INDEX = 3
hook the probe up to the S6 input, pin 10.
For PROBE_INDEX = 4, it's S7, pin 11
use the G38.2 code
variable #5061 receives X value
variable #5062 receives Y value
variable #5063 receives Z value
(PROBEOPEN probe.out)
G38.2 X1.0 G38.2 Y1.0
(PROBECLOSE)

Notes on using phase drive with EMC

To specify this, just put the following 3 lines in your .ini file:
[EMCMOT]
EMCMOT = freqmod.o
STEPPING_TYPE = 1 or 2 (pick original or table driven code)

It only works for freqmod.o (steppermod.o will come once this is debugged). If you say 0, or leave it out, it uses step-and-direction.

EMC Second Parallel Port Map [aux I/O]

DB25 Pin	Signal/Dir	EMC variable / flags
1	/c0 - Out	SPINDLE_DECREASE_INDEX SPINDLE_DECREASE_POLARITY = 1
2	d0 - Out	SPINDLE_REVERSE_INDEX SPINDLE_REVERSE_POLARITY = 0
3	d1 - Out	SPINDLE_FORWARD_INDEX SPINDLE_FORWARD_POLARITY = 0
4	d2 - Out	n/a
5	d3 - Out	n/a
6	d4 - Out	n/a
7	d5 - Out	n/a
8	d6 - Out	MIST_COOLANT_INDEX MIST_COOLANT_POLARITY = 0
9	d7 - Out	FLOOD_COOLANT_INDEX FLOOD_COOLANT_POLARITY = 0
10	s6 - In	n/a
11	/s7 - In	n/a
12	s5 - In	LUBE_SENSE_INDEX LUBE_SENSE_POLARITY = 1
13	s4 - In	ESTOP_SENSE_INDEX ESTOP_SENSE_POLARITY = 1
14	c1 - Out	SPINDLE_INCREASE_INDEX SPINDLE_INCREASE_POLARITY = 1
15	s3 - In	n/a
16	c2 - Out	ESTOP_WRITE_INDEX ESTOP_WRITE_POLARITY = 1
17	/c3 - Out	SPINDLE_BRAKE_INDEX SPINDLE_BRAKE_POLARITY = 0
18-25	ground	n/a

IBM Parallel Port FAQ/Tutorial The tutorial goes into the gory details of the different parallel port modes and has a lot of info on printer signals and interfacing.

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