Freescale Semiconductor MPC8260 4.3.1.5 SIU Interrupt Mask Registers (SIMR_H and SIMR_L)

System Interface Unit (SIU)
MPC8260 PowerQUICC II Family Reference Manual, Rev. 2
4-22 Freescale Semiconductor
When a pending interrupt is handled, the user clears the corresponding SIPNR bit. However, if an event
register exists, the unmasked event register bits should be cleared instead, causing the SIPNR bit to be
cleared.
SIPNR bits are cleared by writing ones to them. Because the use r can only clear bits in this register, writing
zeros to this register has no effect.
Note that the SCC/FCC/MCC SIPNR bit positions are not changed according to their relative priority.
4.3.1.5 SIU Interrupt Mask Registers (SIMR_H and SIMR_L)
Each bit in the SIU interrupt mask register (SIMR) corresponds to a interrupt source. The user masks an
interrupt by clearing and enables an interrupt by setting the corresponding SIMR bit. When a masked
interrupt occurs, the corresponding SIPNR bit is set, regardless of the SIMR bit although no interrupt
request is passed to the core.
If an interrupt source requests interrupt service when the user clears its SIMR bit, the request stops. If the
user sets the SIMR bit later, a previously pending interrupt request is processed by the core, according to
its assigned priority. The SIMR can be read by the user at any time.
Figure 4-16 shows the SIMR_H register.
012345678910111213 15
FieldFCC1 FCC2 FCC3 — MCC1MCC2 — SCC1 SCC2 SCC3 SCC4 TC2—
Reset 0000_0000_0000_00001
R/W R/W
Addr 0x0x10C0C
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
Field I2C SPI RTT SMC1SMC2 IDMA1 IDMA2 IDMA3 IDMA4 SDMA — TIMER1 TIMER2TIMER3 TIMER4 —
Reset 0000_0000_0000_000101
R/W R/W
Addr 0x10C0E
1 These fields are zero after reset because their corresponding mask register bits are cleared (disabled).
2 MPC8264 and MPC8266 only. Reserved on all other devices.
Figure 4-15. SIPNR_L