Reference Manual

Turbo PMAC/PMAC2 Software Reference
Turbo PMAC Global I-Variables 36
I1 Serial Port Mode
Range: 0 to 3
Units: None
Default: 0
I1 controls two aspects of how Turbo PMAC uses its main serial port. The first aspect is whether PMAC
uses the CS (CTS) handshake line to decide if it can send a character out the serial port. The second
aspect is whether PMAC will require software card addressing, permitting multiple cards to be daisy-
chained on a single serial line.
There are four possible values of I1, covering all the possible combinations:
Setting
Meaning
0
CS handshake used; no software card address required
1
CS handshake not used; no software card address required
2
CS handshake used; software card address required
3
CS handshake not used; software card address required
When CS handshaking is used (I1 is 0 or 2), Turbo PMAC waits for the CS line to go true before it will
send a character. This is the normal setting for real serial communications to a host; it allows the host to
hold off Turbo PMAC messages until it is ready.
When CS handshaking is not used (I1 is 1 or 3), Turbo PMAC disregards the state of the CS input and
always sends the character immediately. This mode permits Turbo PMAC to “output” messages, values,
and acknowledgments over the serial port even when there is nothing connected, which can be valuable in
stand-alone and PLC-based applications where there are SENDS and CMDS statements in the program.
If these strings cannot be sent out the serial port, they can back up, stopping program execution.
When software addressing is not used (I1 is 0 or 1), Turbo PMAC assumes that it is the only card on the
serial line, so it always acts on received commands, sending responses back over the line as appropriate.
When software addressing is used (I1 is 2 or 3), Turbo PMAC assumes that there are other cards on the
line, so it requires that it be addressed (with the @{card} command) before it responds to commands.
The {card} number in the command must match the card number set up with variable I0.
I2 Control Panel Port Activation
Range: 0 to 3
Units: None
Default: 0
I2 allows the enabling and disabling of the control panel discrete inputs on the JPAN connector, should
this connector exist. I2=0 enables these control panel functions; I2=1 disables them. When disabled,
these inputs can be used as general purpose I/O. The reset, handwheel, and wiper inputs on the JPAN
connector are not affected by I2.
On a Turbo PMAC board, when I2=0, the IPOS, EROR and F1ER status lines to JPAN and the
Programmable Interrupt Controller (PIC), and the BREQ status line to the PIC, reflect the hardware-
selected coordinate system (by BCD-coded lines FPDn/ on JPAN); when I2=1, they reflect the software-
addressed coordinate system (&n). (On a Turbo PMAC2, the lines to the PIC always reflect the software-
addressed coordinate system.)
When I2=3, discrete inputs on a JPAN connector are disabled, and the dual-ported RAM control panel
functions are enabled. Refer to the descriptions of DPRAM functions for more detail.