Delta Tau GEO BRICK LV Manual Do Utilizador
Turbo PMAC User Manual
Talking to Turbo PMAC
39
TALKING TO TURBO PMAC
This section covers the basic aspects of communicating with Turbo PMAC from a host computer. At this
level, we are assuming that there is a program for the host computer that processes these communications.
The PMAC Executive Program (Pewin32 Pro) is the most common of these programs.
level, we are assuming that there is a program for the host computer that processes these communications.
The PMAC Executive Program (Pewin32 Pro) is the most common of these programs.
If there will be a host computer in the final application, write custom communications routines for the
host computer as part of the front-end software for the application. That is a more advanced topic, and it
is covered in the Writing a Host Communications Program section. Delta Tau provides communications
libraries for use under Microsoft Windows operating systems.
host computer as part of the front-end software for the application. That is a more advanced topic, and it
is covered in the Writing a Host Communications Program section. Delta Tau provides communications
libraries for use under Microsoft Windows operating systems.
At a basic level, Turbo PMAC can communicate to a host dumb terminal, over any of the ports. The
communications mostly consists of lines of ASCII characters sent back and forth. Of course, most of the
time the host will be a computer with considerably more intelligence, but at root it will talk to the card as
if it were a terminal. The PMAC Executive PC program has a terminal emulator mode to do this directly.
communications mostly consists of lines of ASCII characters sent back and forth. Of course, most of the
time the host will be a computer with considerably more intelligence, but at root it will talk to the card as
if it were a terminal. The PMAC Executive PC program has a terminal emulator mode to do this directly.
Communications Ports
Each version of Turbo PMAC has available multiple communications ports: one or two serial ports, a bus
port, and an optional dual-ported RAM shared-memory communications interface. Different
configurations of the Turbo PMAC will have different types of these interfaces.
port, and an optional dual-ported RAM shared-memory communications interface. Different
configurations of the Turbo PMAC will have different types of these interfaces.
Turbo PMAC can communicate simultaneously over multiple ports, without the communications on
different ports interfering with each other (the original PMAC family does not have this capability). This
gives the user useful capabilities such as employing both a host computer and an operator pendant, or
using one port for the applications communications and another for simultaneous monitoring and
debugging.
different ports interfering with each other (the original PMAC family does not have this capability). This
gives the user useful capabilities such as employing both a host computer and an operator pendant, or
using one port for the applications communications and another for simultaneous monitoring and
debugging.
Serial Communications Ports
Turbo PMAC controllers have one or two serial communications ports that provide a simple
communications interface to host computers, terminals, or other devices. Depending on the particular
configuration and port, the port can use RS-232 or RS-422 signal levels.
communications interface to host computers, terminals, or other devices. Depending on the particular
configuration and port, the port can use RS-232 or RS-422 signal levels.
Main Serial Port
Each configuration of Turbo PMAC comes standard with a serial communications port. Depending on
the configuration, this may be available at RS-232 levels (single-ended +/-10V) only, RS-422 levels
(differential 5V) only, or user-selectable by jumpers between the two levels. The RS-422 circuits on a
Turbo PMAC are capable of interfacing directly to an RS-232 port on a computer, but noise margins are
significantly reduced, so communications may be quite susceptible to electromagnetic noise. If both
levels are available, it is important to realize that this is only a single port, and that only one voltage level
may be used at any given time.
the configuration, this may be available at RS-232 levels (single-ended +/-10V) only, RS-422 levels
(differential 5V) only, or user-selectable by jumpers between the two levels. The RS-422 circuits on a
Turbo PMAC are capable of interfacing directly to an RS-232 port on a computer, but noise margins are
significantly reduced, so communications may be quite susceptible to electromagnetic noise. If both
levels are available, it is important to realize that this is only a single port, and that only one voltage level
may be used at any given time.
The baud rate for the main serial port is set by variable I54. At power-up reset, Turbo PMAC sets the
active baud-rate-control register based on the setting of I54 and the CPU speed as set by I52, as the baud-
rate frequency is divided down from the CPU’s operational frequency. The factory default baud rate is
38,400. This baud rate will be selected automatically on re-initialization of the Turbo PMAC, either
through use of the re-initialization jumper or the $$$*** command. To change the baud rate, change the
setting of I54, copy this new setting to non-volatile memory with the SAVE command, then reset the
Turbo PMAC. Re-establish communications at the new baud rate.
active baud-rate-control register based on the setting of I54 and the CPU speed as set by I52, as the baud-
rate frequency is divided down from the CPU’s operational frequency. The factory default baud rate is
38,400. This baud rate will be selected automatically on re-initialization of the Turbo PMAC, either
through use of the re-initialization jumper or the $$$*** command. To change the baud rate, change the
setting of I54, copy this new setting to non-volatile memory with the SAVE command, then reset the
Turbo PMAC. Re-establish communications at the new baud rate.