11/45 progress

[Jay West]

Tony wrote...
> Odd... That implies your console card is not responding. Maybe it's
> defective too.
Kinda what I figured :)

>But IIRC there's at
> least one bit (my memory is weak on this, but I think it's the interrupt
> enable bit, maybe bit 6) that you should be able to read and write from
> the panel.
Ah ok, good thing I printed off those engineering notes. I'll track down the 
interrupt enable bit and try that.

> My idea was going to be to hang a terminal off the card (assuming you
> have an RS232 lead and can decode the word foramt and baud rate settings
> [1] and then try writing to the transmit data registers at 777566 or
> 777656. See if you can transmit chracters to the terminal.
I have the appropriate cable from the card to mate & lock, I'll cobble 
something together to go from that to a terminal. I thought you were saying 
just to read/write to that register. I'll decode the rest of the settings on 
the board (other than the register address) including the crystal, and hook 
up a terminal.

> [1] The baurd rate is set by a rotary switch on the card and by the
> frequency of the crystal fitted. I found the quickest way to work it out
> was to connect a frequncy counter to pin 17 (Rx clock) and 40 (Tx clock)
> of the UART chip. Then divide that frequency by 16 to get the baud rate.
> But I guess you don't have a frequency counter sitting on top of your
> machine...
Well, as of now, my HP 5315A counter is sitting on top of it :) I'll make 
the measurements tomorrow. I'm glad you said that, because I noticed the 
rotary switches for TX & RX speed settings weren't labled (1-10) on the 
card. This way I can be sure. However, my usual question follows... if I 
connect to 17 and 40 (separately of course), what is the ground reference 
location for those measurements? I never seem to know where to hook the 
other lead :\ In this case, if I can find a pinout for the UART, I'm sure 
that would be a good spot for ground.

> I am going to get you to repair that machine properly -- without swapping
> boards -- even if I have to get on the next p'lane across the Pond and
> show you where to stick your 'scope probe ;-)
I'm willing to learn, travel won't be necessary, just an informed instructor 
:)

> You have got them in the right way round, with the resistors towards the
> front of the machine, I hope! If not, you will have all sorts of
> problems.
Yes, component side of all boards is towards the front, including the two 
terminators.

> Ge ta Unibus pinout, grabe the logic probe, and see if the data lines
> ever go low on a CPU (frontpanel) write operation.
If I can get some 11/45 time this weekend, I will do just that.

Thanks!

Jay