The interrupt set register (ISR) allows to manually set the maskable interrupts (INT15-INT4) in the interrupt flag register (IFR). Writing a 1 to any of the bits in ISR causes the corresponding interrupt flag (IFn) to be set in IFR. Writing a 0 to any bit in ISR has no effect. It is not possible to set any bit in ISR to affect NMI or reset. The ISR is shown in Figure 8-34 and described in Table 8-318.
Note: Any write to ISR (by the MVC instruction) effectively has one delay slot because the results cannot be read (by the MVC instruction) in IFR until two cycles after the write to ISR.
Any write to the interrupt clear register (ICR) is ignored by a simultaneous write to the same bit in ISR.
Figure 8-34 Interrupt Set Register (ISR) | IS15 | IS14 | IS13 | IS12 | IS11 | IS10 | IS9 | IS8 | IS7 | IS6 | IS5 | IS4 | Reserved |
| W-0 | W-0 | W-0 | W-0 | W-0 | W-0 | W-0 | W-0 | W-0 | W-0 | W-0 | W-0 | R-0 |
| LEGEND: R = Read only; W = Writeable by the MVC instruction; -n = value after reset |
Table 8-318 Interrupt Set Register (ISR) Field Descriptions| Bit | Field | Value | Description |
|---|
| 31-16 | Reserved | 0 | Reserved. The reserved bit location is always read as 0. A value written to this field has no effect. |
| 15-4 | ISn | | Interrupt set. |
| 0 | Corresponding interrupt flag (IFn) in IFR is not set. |
| 1 | Corresponding interrupt flag (IFn) in IFR is set. |
| 3-0 | Reserved | 0 | Reserved. The reserved bit location is always read as 0. A value written to this field has no effect. |