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handlers can examine EPSR value in the stacked PSR to indicate the operation that is at fault. See
2.1.3.5.4 Interruptible-continuable instructions
When an interrupt occurs during the execution of an LDM or STM instruction, the processor:
stops the load multiple or store multiple instruction operation temporarily
stores the next register operand in the multiple operation to EPSR bits[15:12].
After servicing the interrupt, the processor:
returns to the register pointed to by bits[15:12]
resumes execution of the multiple load or store instruction.
When the EPSR holds ICI execution state, bits[26:25,11:10] are zero.
2.1.3.5.5 If-Then block
The If-Then block contains up to four instructions following a 16-bit IT instruction. Each instruction in
the block is conditional. The conditions for the instructions are either all the same, or some can be the
2.1.3.6 Exception mask registers
The exception mask registers disable the handling of exceptions by the processor. Disable exceptions
where they might impact on timing critical tasks.
To access the exception mask registers use the MSR and MRS instructions, or the CPS instruction to
2.1.3.6.1 Priority Mask Register
The PRIMASK register prevents activation of all exceptions with configurable priority. See the register
31
Reserved
1 0
PRIMASK
Table 2.7. PRIMASK register bit assignments
Bits
Name
Function
[31:1]
-
Reserved
[0]
PRIMASK
0 = no effect
1 = prevents the activation of all exceptions with configurable priority.
2.1.3.6.2 Fault Mask Register
The FAULTMASK register prevents activation of all exceptions except for Non-Maskable Interrupt (NMI).
See the register summary in
Table 2.2 (p. 7) for its attributes. The bit assignments are: