6 Aug
2022
6 Aug
'22
8:26 a.m.
Sort of. The grant cards pass NPG and DMA signals on SPC slots. It's
important to remember that the old "knuckle buster" types of cards
passed npg only and you had to cut the DMA jumper if you wanted to use a
DMA card in that slot. Once you cut the DMA jumper you needed either a
DMA card in there going forward or a 7273 style grant card.
It's a requirement. Without NPG the processor won't respond because it's
waiting for a SACK timeout reply from the terminator.
Fun stuff. There are *so* many variants on Unibus it's not funny.
C
On 8/6/2022 11:18 AM, Rob Jarratt via cctalk wrote:
The 11/24 System Technical Manual says that the
terminator (M9302 or M9312)
must be installed in the last slot (slot 9) of the backplane, and that all
empty slots must have a grant card. What I am not clear on is what they mean
by an "empty" slot. Specifically, if I have the CPU, the M7134 memory map
and a memory board installed in slots 1-3 and then nothing else except the
terminator in slot 9, does this mean I have to install grant cards in slots
4-8?
My guess is that this isn't a requirement because the grant cards go in rows
C and D while the terminator is rows A and B, but I am hoping someone can
confirm this for me please?
Thanks
Rob