User's Manual

PMAC2 User Manual
82 PMAC2 General Purpose I/O Use
In addition, the bi-directional buffer IC for each byte has a direction control line accessible as a software
control bit. These control lines and bits must match the ASIC direction bits. In the PC-bus versions of
the PMAC2, the buffer direction control bits are at PMAC2 address Y:$E800, with bits 4 and 5
controlling the two bytes of the JTHW port. A bit value of 0 specifies input; 1 specifies output.
Suggested M-variable definitions are:
M61->Y:$E800,4 ; Buffer direction control for DAT0 to DAT7
M63->Y:$E800,5 ; Buffer direction control for SEL0 to SEL7
In the VME-bus versions of the PMAC2, the buffer direction control bits are at PMAC2 address
Y:$E802, with bits 0 and 1 controlling the two bytes of the JTHW port. A bit value of 0 specifies input; 1
specifies output. Suggested M-variable definitions are:
M61->Y:$E802,0 ; Buffer direction control for DAT0 to DAT7
M63->Y:$E802,1 ; Buffer direction control for SEL0 to SEL7
To change either of these I/O bytes, it must be done by user programs (usually this is done in PLC 1
acting as a reset PLC, scanning through once on power-up/reset, then disabling itself).
Inversion Control
Each line on the JTHW port is individually controllable as to whether it is an inverting I/O point (0=+5V;
1=0V) or a non-inverting I/O point (0=0V; 1=+5V). Register X:$C086 contains the inversion control bits:
X:$C086 bits 0 to 7 control DAT0 to DAT7, respectively
X:$C086 bits 8 to 15 control SEL0 to SEL7, respectively
A value of 0 in the control bit sets the corresponding I/O point as non-inverting. A value of 1 in the
control bits sets the corresponding I/O point as inverting. At power-up/reset, PMAC automatically sets
all of the I/O points on the JTHW port as non-inverting. To use any of the multiplexed I/O accessory
boards on the JTHW port, all I/O points on the port must be left non-inverting.
Alternate Uses
Each general-purpose I/O point on the JTHW port has an alternate use as a supplemental fixed-use I/O
point on a supplemental machine interface channel (1* or 2*). The points are individually controllable as
to general-purpose use or fixed use by control register Y:$C086. Refer to this register in the memory-I/O
map to see the alternate uses of each point. At power-up/reset, PMAC2 sets up all of the I/O points on the
port for general purpose use automatically.
Note:
Because of the byte-wide direction-control buffer ICs, it is not possible to use all
of the I/O points on the JTHW in their alternate uses.
JANA Port
The JANA port is present only if Option 12 is ordered for the PMAC2. Option 12 provides eight 12-bit
analog inputs (ANAI00-ANAI07). Option 12A provides eight additional 12-bit analog inputs (ANA08-
ANAI15) for a total of 16 inputs.
Hardware Characteristics
The analog inputs can be used as unipolar inputs in the 0V to +5V range, or bipolar inputs in the -2.5V to
+2.5V range. Each input has a 470Ω input resistor in-line, and a 0.033 µF resistor to ground. This
provides a 16 µsec time constant on each input line.
The analog-to-digital converters on PMAC2 require +5V and -12V supplies. These supplies are not
isolated from digital +5V circuitry on PMAC If the PMAC2 is plugged into the bus (PC or VME), these
supplies are taken from the bus power supply. In a standalone application, these supplies must be brought
in on terminal block TB1.