ST92141 STMicroelectronics, ST92141 Datasheet - Page 50

• Manufacturer Part Number: ST92141
• Description: 8/16-bit Mcu For 3-phase Ac Motor Control
• Manufacturer: STMicroelectronics

ST92141 - INTERRUPTS
NMI/WKP0 LINE MANAGEMENT (Cont’d)
3.9.1 NMI/Wake-Up Event Handling in Run
mode
The four external lines WKUP0/NMI, WKUP1-3
can also be used when the device is in Run Mode.
In addition, if the WKUP0/NMI line is used and the
NMI and WKUP0 events are enabled by program-
ming the CPU, IMC and WUIMU registers, a tran-
sition on the input pin can generate the following
events:
– IMC: the six output phases UH/UL/VH/VL/WH/
– CPU: the NMI pending bit of the CICR register is
Note 1: The NMI pending bits of the IMCIVR reg-
ister must be cleared by software in the NMI rou-
tine, whereas the NMI pending bit of the CICR
register is cleared by hardware when NMI routine
is acknowledged.
Note 2: The external NMI/WKUP0 event is flagged
in the NMI pending bit of the IMCIVR register. The
NMI routine must clear this bit. This operation must
occur after disactivation of the NMI/WKUP0 line
(otherwise, the next NMI/WKUP0 event will be
lost, if the CPU is sensitive to a rising edge on the
NMI input).
The flexibility of the ST9 also allows the use of the
NMI/WKUP0 line as a wake up function only or as
a Non Maskable Interrupt only.
WARNING:
1. The NMI management implemented in the
– No glitches should occur on the pin to avoid un-
– A minimum pulse width is requested for the pin
2. The WKUP0-3 management implemented in
50/179
WL are released in High Impedance. The NMI bit
of the IMCIVR register is automatically set to “1”.
A non maskable interrupt request is then sent to
the CPU.
set and the corresponding NMI interrupt routine
is immediately executed.
intentional NMI/wake up requests.
activation (refer to ST92141 Electrical Specifica-
tion).
ST92141 imposes the following constraints on
the P5.3 (NMI/WKUP0) I.O pin:
the ST92141 imposes the following constraints
on the P5.0 (WKUP1), P5.2 (WKUP0), P3.2
(WKUP3) and P3.6 (WKUP2):
1
– No glitches should occur on WKUP0-3 pins to
3.9.2 NMI/Wake-Up Event Handling in STOP
mode
The ST92141 enters Stop Mode by software writ-
ing a special Stop bit setting sequence in the
WUCTRL register of the WUIMU. After entering
Stop Mode, the device can be woken up by one of
the four Wake Up external lines (refer to
3.12 WAKE-UP / INTERRUPT LINES MANAGE-
MENT UNIT
In addition, if the WKUP0/NMI line is used and the
NMI and WKUP0 events are enabled by program-
ming the CPU, IMC and WUIMU registers, a tran-
sition on the input pin can generate the following
events:
– IMC: the six output phases UH/UL/VH/VL/WH/
– WUIMU: the NMI/WKUP0 activation wakes up
– CPU: the NMI pending bit of the CICR register is
Note: The NMI pending bits of the IMCIVR register
must be cleared by software in the NMI routine,
whereas the NMI pending bit of the CICR register
is cleared by hardware when the NMI routine is ac-
knowledged.
3.9.3 Unused Wake Up Management Unit lines
The WUIMU can manage up to 16 External-Inter-
rupt/ Wake up lines. Usually, only a subset of
these 16 lines is used.
In the ST92141, 4 lines out of 16 are available as
external lines (WKUP0/1/2/3) but the Pending and
Mask bits of the unused lines (WKUP4 to WKUP
15) are also accessible by software (refer to
tion 3.12 WAKE-UP / INTERRUPT LINES MAN-
AGEMENT UNIT
ble to generate a software interrupt by disabling
the Mask and by setting the Pending bit of an un-
used channel.
avoid unintentional requests.
WL are released in High Impedance. The NMI bit
of the IMCIVR register is automatically set to “1”.
A non maskable interrupt request is then sent to
the CPU.
the ST92141 from Stop mode, allowing the CPU
to acknowledge the NMI request from IMC
set and the corresponding NMI interrupt routine
is executed as soon as the ST92141 is exited
from Stop mode.
(WUIMU).
(WUIMU)). Therefore, it is possi-
Section
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