M451
May. 4, 2018
Page
238
of
1006
Rev.2.08
M4
51
S
E
RI
E
S
T
E
CH
NICA
L RE
F
E
R
E
NC
E
M
A
NU
A
L
71
55
USBOTG_INT
USB OTG interrupt (M45xG/M45xE Only)
72
56
CAN0_INT
CAN0 interrupt
73
57
Reserved
Reserved
74
58
SC0_INT
Smart card host 0 interrupt
75
59
Reserved
Reserved
76
60
Reserved
Reserved
77
61
Reserved
Reserved
78
62
Reserved
Reserved
79
63
Reserved
Reserved
Table 6-7 Interrupt Number Table
Operation Description
6.2.10.2
NVIC interrupts can be enabled and disabled by writing to their corresponding Interrupt Set-
Enable or Interrupt Clear-Enable register bit-field. The registers use a write-1-to-enable and write-
1-to-clear policy, both registers reading back the current enabled state of the corresponding
interrupts. When an interrupt is disabled, interrupt assertion will cause the interrupt to become
Pending, however, the interrupt will not activate. If an interrupt is Active when it is disabled, it
remains in its Active state until cleared by reset or an exception return. Clearing the enable bit
prevents new activations of the associated interrupt.
NVIC interrupts can be pended/un-pended using a complementary pair of registers to those used
to enable/disable the interrupts, named the Set-Pending Register and Clear-Pending Register
respectively. The registers use a write-1-to-enable and write-1-to-clear policy, both registers
reading back the current pended state of the corresponding interrupts. The Clear-Pending
Register has no effect on the execution status of an Active interrupt.
NVIC interrupts are prioritized by updating an 8-bit field within a 32-bit register (each register
supporting four interrupts).
The general registers associated with the NVIC are all accessible from a block of memory in the
System Control Space and will be described in next section.
