MAS281 Dynex, MAS281 Datasheet - Page 9

• Manufacturer Part Number: MAS281
• Description: MIL-STD-1750A Microprocessor
• Manufacturer: Dynex

2.2.23 TRIGGER-GO CLOCK (TGCLK)
counter. The trigger-go counter counts at the same frequency
as TGCLK.
2.2.24 TRIGGER-GO DISCRETE (TGO)
counter overflows, i e., the counter rolls over to 0000. It returns
to the high state when the trigger-go counter is reset by
software via the GO XIO command.
2.2.25 DISABLE TIMER (DTIMER)
well as the trigger-go counter. A low also disables DMA access
by forcing DMAE low and DMAKN high. Raising DTIMERN
allows timers A and B and the trigger-go counter to resume
counting from the value at which they were stopped. A high
also allows normal DMA operation.
2.2.26 DISABLE TIMEOUT (DTO)
fault timeout circuitry.
2.2.27 POWER DOWN INTERRUPT (PWRD)
by a SYNCN high-to-low transition. This sets pending interrupt
0. This is the highest priority interrupt and cannot be masked or
disabled.
2.2.28 USER INTERRUPTS (INT02,08,10,11,13 AND 15)
the Pl register by a SYNCN high-to-low transition and will set
pending interrupt levels 2, 8, 10, 11, 13, and 15, respectively.
Level 2 is the highest priority user level while level 15 is the
lowest priority. These interrupts are maskable and can be
disabled. Unused inputs should be pulled up to VDD.
Register using the RPI 0002 instruction.]
This clock input is used by the internal 16-bit trigger-go
This active low output goes low whenever the trigger-go
A low on this active low input disables timers A and B as
A low on this active low input will reset and disable the bus
A low on this active low input is captured in the Pl register
A low on any of these active low inputs will be captured in
[NOTE: The INTO2 service routine should clear the PI
Bit
15
14
13
12
11-0
Table 1: Configuration Register Bit Assignment
Device
Console
MMU
BPU
Output Discrete Register
Unused
2.2.29 I/0 DEDICATED INTERRUPTS (IOI1 & IOI2)
register by a SYNCN high-to-low transition and will set pending
interrupt levels 12 and 14, respectively. Unused inputs should
be pulled up to VDD.
to internal machine interrupts.]
2.2.30 MEMORY PROTECT ERROR (MPROE)
high-to-low transition, is used to inform the module that an
access fault, execute protect, or write protect violation has
been detected. Bit O of the module Fault Register (FT) is set if
this signal goes low during a memory cycle; bit 1 is set if it goes
low during a DMA cycle. Either condition immediately sets
pending interrupt level 1 and in the case of a memory cycle
error, causes the currently executing MIL-STD-1750A
instruction to be aborted.
memory management, and / or block protect hardware is
responsible for preventing the erroneous bus cycle from
accessing memory. To effectively use this feature, MPROEN
should be pulled low prior to the high-to-low SYNCN transition
of the next machine cycle. This can easily be accomplished by
injecting wait states to hold off the DSN rising edge (write
cycle) and the SYNCN falling edge (read cycle) until the
system protection circuitry can decide whether or not to allow
the transaction.
2.2.31 MEMORY PARITY ERROR (MPE)
high-to-low transition, is used to inform the module that a parity
error has been detected during a memory transfer. Bit 2 of the
module Fault Register (FT) is set when this signal goes low.
This, in turn, causes pending interrupt level 1 to be set.
2.2.32 PROGRAMMED I/O PARITY ERROR (PIOPE)
high-to-low transition, is used to inform the module that a parity
error has been detected during an external l/O transfer. Bit 3 of
the module Fault Register (FT) is set when this signal goes
low. This, in turn, causes pending interrupt level 1 to be set.
2.2.33 DMA PARITY ERROR (DMAPE)
high-to-low transition, is used to inform the module that a parity
error has been detected during a DMA data transfer. Bit 4 of
the module Fault Register (FT) is set when this signal goes low
This, in turn, causes pending interrupt level 1 to be set.
2.2.34 EXTERNAL ADDRESS ERROR (EXADE)
high-to-low transition, is used to inform the module that a
system address error has been detected. Bit 8 of the module
Fault Register (FT) is set when this signal goes low during a
A low on either IOI1N or IOI2N will be captured in the Pl
[NOTE: Interrupt levels 1, 3, 4, 5, 6, 7, and 9 are dedicated
A low on this active low input, captured by the SYNCN
A low on this active low input, captured by the SYNCN
A low on this active low input, captured by the SYNCN
A low on this active low input, captured by the SYNCN
A low on this active low input, captured by the SYNCN
Although the MAS281 aborts the macroinstruction, system
MAS281
9/55