daver2
10k Member
Marty,
Yes - regular DEPOSIT and EXAMINE from the front panel is all you need.
I am just trying to reduce the MMU problem to the 'smallest' unit where we can see some degree of not operating correctly and to proceed from there.
With the M8116 IN; your PDP-11/45 should quite happily run test programs etc.
With the MMU cards in place of the M8116 - does this combination still work correctly with programs that do NOT 'play' with the MMU hardware? On a reset (M8108 pins 1 and 13 of IC E58 going LOW) the outputs from E58 (pins 5 and 9) should both go low and stay low). E58 controls the maintenance bit (08) and the relocation enable bit (00) of Status Register 0. You should also be able to read this register at any time by EXAMINING SR0 at 777572. Bits 00 and 08 should always be a '0'.
With the MMU disabled (bit 00 of SR0 = '0') the 74157 MUX's of M8107 E23, E24, E32 and E33 should be selecting the 'non-MMU address lines' and forwarding them to UNIBUS-A via the M8107 on drawing (SAPN).
I suppose that's one more question for me to ask you - are you using memory on UNIBUS-A or FASTBUS? The UNIBUS drivers are on sheet SAPN whilst the FASTBUS outputs are directly taken from the multiplexer on drawing SAPJ.
If the 'non-MMU enabled' stuff works fine - we can work on the 'MMU enabled' stiff later.
Incidentally, just setting the registers to '0' only tests for one failure mode. I use the following:
Stuck '1'.
Stuck '0'.
Shorted to adjacent.
As my 'code words' for determining faults. So, to take a simple register, setting a 16-bit register to 177777 should check for a bit being stuck at '0'. You would set the register to 000000 to check for a stuck '1'. But you would have to use a 'pattern' of bits to check for an 'adjacent short' such as 000000, 000001, 000003, 000007, etc.
You would do this for a single register at first (to check the bus buffers out) then you would need to do this for multiple registers to check for stuck '0', '1' and adjacent shorts on the address bus (i.e. can I correctly address the correct thing).
The above probably sounds like a bit of 'Double Dutch' due to my explanation...
Dave
Yes - regular DEPOSIT and EXAMINE from the front panel is all you need.
I am just trying to reduce the MMU problem to the 'smallest' unit where we can see some degree of not operating correctly and to proceed from there.
With the M8116 IN; your PDP-11/45 should quite happily run test programs etc.
With the MMU cards in place of the M8116 - does this combination still work correctly with programs that do NOT 'play' with the MMU hardware? On a reset (M8108 pins 1 and 13 of IC E58 going LOW) the outputs from E58 (pins 5 and 9) should both go low and stay low). E58 controls the maintenance bit (08) and the relocation enable bit (00) of Status Register 0. You should also be able to read this register at any time by EXAMINING SR0 at 777572. Bits 00 and 08 should always be a '0'.
With the MMU disabled (bit 00 of SR0 = '0') the 74157 MUX's of M8107 E23, E24, E32 and E33 should be selecting the 'non-MMU address lines' and forwarding them to UNIBUS-A via the M8107 on drawing (SAPN).
I suppose that's one more question for me to ask you - are you using memory on UNIBUS-A or FASTBUS? The UNIBUS drivers are on sheet SAPN whilst the FASTBUS outputs are directly taken from the multiplexer on drawing SAPJ.
If the 'non-MMU enabled' stuff works fine - we can work on the 'MMU enabled' stiff later.
Incidentally, just setting the registers to '0' only tests for one failure mode. I use the following:
Stuck '1'.
Stuck '0'.
Shorted to adjacent.
As my 'code words' for determining faults. So, to take a simple register, setting a 16-bit register to 177777 should check for a bit being stuck at '0'. You would set the register to 000000 to check for a stuck '1'. But you would have to use a 'pattern' of bits to check for an 'adjacent short' such as 000000, 000001, 000003, 000007, etc.
You would do this for a single register at first (to check the bus buffers out) then you would need to do this for multiple registers to check for stuck '0', '1' and adjacent shorts on the address bus (i.e. can I correctly address the correct thing).
The above probably sounds like a bit of 'Double Dutch' due to my explanation...
Dave