Reference Guide

PMAC Quick Reference Guide
22 Installing and Configuring PMAC
Establishing Host Communications
Either the Executive or Setup program can be used to establish initial communications with the card.
Both programs have menus that tell the PC where to expect to find the PMAC and how to communicate
with it at that location. If telling it to look for PMAC on the bus, also tell it PMAC’s base address on the
bus (this was set up with jumpers on PMAC). If telling it to look for PMAC on a COM port, tell it the
baud rate (this was set up with jumpers or switches on the PMAC). Once the program knows where and
how to communicate with PMAC, it will attempt to find PMAC at that address by sending a query
command and waiting for the response. If it gets the expected type of response, it will report that it has
found PMAC. If it does not get the expected type of response after several attempts, it will report that it
has not found PMAC.
Terminal Mode Communications
Once the program reports that it has found PMAC, the program should be in terminal emulation mode, so
that the PC is acting as a dumb terminal to PMAC. Check to see if a response is received by typing
I10<CR>. (<CR> means carriage return — the Enter or Return key). PMAC should respond with a
six or seven digit number. If the expected results are not received, check the following:
1. Make sure the green LED (power indicator) on PMAC’s CPU board is ON. If it is not, find out why
PMAC is not getting a +5V voltage supply.
2. Make sure the red LED (watchdog timer indicator) on PMAC’s CPU board isOFF. If it is ON, make
sure PMAC is getting very close to 5V supply – at less than 4.75V, or the watchdog timer will trip,
shutting down the card. The voltage can be probed at pins 1 and 3 of the J8 connector (A1 and A2 on
the PMAC VME). If the voltage is satisfactory, follow these steps:
• Turn off PMAC or the Host computer where it is plugged into.
• Place the Jumper E51 (the hardware re-initialization jumper) and turn PMAC back on.
• If PMAC is in bootstrap mode, send a <CONTROL-R> character to PMAC to bypass the
firmware download.
• If communications are successful type $$$*** and SAVE in the terminal window.
• Turn off PMAC, remove the jumper E51 and try communications again.
Bus Communications
3. Make sure that the bus address jumpers (E91-E92, E66-E71) set the same address as the bus address
on the Executive program.
4. If there is something else on the bus at the same address, try changing the bus address to see if
communications can be established at a new address. Usually, address 768 (300 hex) is open.
Serial Communications
5. Verify that the proper port on the PC is being used. Make sure that the Executive program is
addressing the COM1 port, which is cabled out of the COM1 connector.
6. The baud rate specified in the Executive program should match the baud rate setting of the E44-E47
jumpers on PMAC.
7. With a breakout box or oscilloscope, make sure there is action on the transmit lines from the PC as
while typing into the Executive program. If not, there is a problem on the PC end.
8. Probe the return communication line while giving PMAC a command that requires a response (e.g.
<CONTROL-F>). If there is no action, change jumpers E9-E16 on PMAC to exchange the send and
receive lines. If there is action, but the host program does not receive characters, RS-232 might be
receiving circuitry that does not respond at all to PMAC’s RS-422 levels. If there is another model of
PC available, try using it as a test (most models accept RS-422 levels quite well). If the computer still
will not accept the signals, try a level-conversion device, such as Acc-26.