2.5.1.3.7 Interrupt Program Status Register

The IPSR contains the exception type number of the current Interrupt Service Routine (ISR). See the register summary in Table 2-2 for its attributes. The following table lists the bit assignments.

Table 2-5. IPSR Bit Assignments
Bits Name Function
[31:9] Reserved
[8:0] ISR_NUMBER This is the number of the current exception:

0 = Thread mode

1 = Reserved

2 = NMI

3 = HardFault

4 = MemManage

5 = BusFault

6 = UsageFault

7-10 = Reserved

11 = SVCall

12 = Reserved for Debug

13 = Reserved

14 = PendSV

15 = SysTick

16 = IRQ0.

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255 = IRQ239

For more information, see 2.5.3.2 Exception Types.