User's Manual

PMAC2 User Manual
Using the PMAC2 to Interrupt the Host Computer 93
M112=1 ; Prepare to set EQU1 high
M111=1 ; Enable writing of M112 value to EQU1
; (M111 is self-clearing)
To clear EQU1 in advance of the next interrupt, the code is:
M112=0 ; Prepare to set EQU1 low
M111=1 ; Enable writing of M112 value to EQU1
; (M111 is self-clearing)
If I56 and I58 are both set to 1 to enable DPRAM ASCII communications with interrupts, PMAC2 will
generate an interrupt automatically on the EQU1 line each time it has loaded a response line into the
DPRAM ASCII response buffer. With this function active, no other use of the EQU1 line should be made.
Note that this interrupt is not available on PMAC2 PC Ultralite boards at this time, so the DPRAM ASCII
interrupt function is also not available on these boards.
Position Compare 5 (EQU5)
[PMAC2 PC only] The EQU5 signal goes true as toggled by the position compare registers and/or the
direct-write feature of the position compare function. The direct-write feature permits the use of this
signal as a software-generated interrupt from PMAC2 programs. With the suggested M-variable
definitions, the code to trigger a software-generated interrupt is:
M512=1 ; Prepare to set EQU5 high
M511=1 ; Enable writing of M512 value to EQU5
; (M511 is self-clearing)
To clear EQU5 in advance of the next interrupt, the code is:
M512=0 ; Prepare to set EQU5 low
M511=1 ; Enable writing of M512 value to EQU5
; (M511 is self-clearing)
On the PMAC2 Lite, EQU2 provides this interrupt instead of EQU5. Suggested M-variables M212 and
M211 can be used in place of M512 and M511 in the above examples. This interrupt is not currently
available on the PMAC2 PC Ultralite board.
Watchdog
The watchdog signal goes true when the PMAC2 watchdog timer trips and shuts down the card.