User's Manual

PMAC User Manual
8 Getting Started with PMAC
PMAC with Options 4A, 5A, and 5B
If the jumper E51 is ON when a PMAC with the Option CPU executes its reset cycle, PMAC enters a
special re-initialization mode that permits the downloading of new firmware. In this mode, the PMAC can
communicate over the serial port only at a baud rate of 38,400, regardless of the setting of the baud rate
jumpers. Bus communications is also possible on PMAC with bootstrap version 1.01 and newer (most
PMAC have one of these versions). To verify the bootstrap version, type the command VER while
communicating to PMAC in bootstrap mode.
To bypass the download operation in this mode, send a <CONTROL-R> character to PMAC. This puts
PMAC in the normal operational mode with the existing firmware. Factory default values for I-variables,
conversion table settings, and bus addresses for DPRAM and VME are copied from the firmware section of
flash memory into active memory. The saved values of these values are not used, but they are kept in the
user section of flash memory.
For more information on PMAC bootstrap mode and downloading new firmware, refer to the PROM
Update Specification sheet included with the PROM.
Connecting PMAC to the Host Computer
Bus Connection
Caution:
With the board plugged into the bus, it will pull +5V power from the bus
automatically. In this case, there must be no external +5V supply, or the two
supplies will fight each other, possibly causing damage.
With computer power off, plug the PMAC into an open bus slot. The PMAC Lite requires one slot on the
bus, the PMAC PC requires 1-1/2 slots (permitting a half-size board in the next slot), the PMAC VME
requires two slots (one double slot), and the PMAC STD requires two slots for the 4-channel version, and
three slots for the 8-channel version.
Serial Port Connection
For serial communications, use a serial cable to connect the PC’s COM port to the PMAC serial port
connector (J4 on PMAC PC, -Lite, and -VME; J1 on PMAC STD’s bottom board). Delta Tau provides
cables for this purpose: Acc-3D connects PMAC PC or VME to a DB-25 connector; Acc-3L connects
PMAC Lite to a DB-9 connector; and Acc-3S connects PMAC STD to a DB-25 connector. Standard DB-
9-to-DB-25 or DB-25-to-DB-9 adapters may be needed for a particular setup.
If using the Acc-26 Serial Communications converter, connect from the PC COM port to Acc-26 with a
standard DB-9 or DB-25 cable, and from Acc-26 to PMAC using the cable provided with Acc-26. Since
the serial ports on PMAC PC and PMAC VME are RS-422, this accessory can provide the level conversion
between RS-232 and RS-422 (communications is possible without this conversion, but at reduced noise
margin). Because the conversion is optically isolated, the accessory also helps prevent noise and ground
loop problems.
Note:
If the PMAC is not plugged into a bus, it will need an external 5V supply to power
its digital circuits. The +5V line from the supply should be connected to pin 1 or 2
of the JMACH connector (usually through the terminal block), and the digital
ground to pin 3 or 4.