ST92141 STMicroelectronics, ST92141 Datasheet - Page 124

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

ST92141 - 3-PHASE INDUCTION MOTOR CONTROLLER (IMC)
INDUCTION MOTOR CONTROLLER (Cont’d)
7.4.7 NMI management
Figure 71
is managed by the IMC peripheral.
After an ST9 reset, the NMIE bit in the PCR1 reg-
ister is cleared, which means that NMI signal com-
ing from the external pin is sent, as is, to the ST9
core without affecting the IMC peripheral.
If the NMIE bit is set, when an NMI event occurs
on the external pin, it will be acknowledged (de-
pending on the value of the NMIL bit in the PSR
register). In this case:
– The NMI bit in the IMCIVR register is set
– The dedicated output pins of the IMC are put in
– A high level signal is sent to the ST9 Top Level
– The OPE bit is cleared (as the NMI interrupt sig-
Figure 71. NMI management by the IMC peripheral
124/179
high impedance
interrupt
nal is no longer active)
9
shows how the external input NMI signal
NMI to ST9 core
NMI from EXT pin
0
1
NMIE
bit
Notes:
1. Because the signal to the ST9 top level interrupt
is active high, the TLTEV bit in the EIVR register
must be set.
2. When the user wants to leave the NMI interrupt
routine, it is strongly recommended to verify, be-
fore leaving the routine, that the NMI pending bit
(bit 3 of IMCIVR) is really at “0”. To do this, the
user can try to write the NMI pending bit to “0” re-
peatedly until it has successfully been cleared.
The NMI pending bit in IMCIVR register can be
written to “0” only if the external NMI signal is no
longer active. This makes sure that no NMI event
will be lost. If the user leaves the NMI interrupt rou-
tine without clearing the NMI pending bit, no other
NMI interrupt can be issued afterwards because
the ST9 top level interrupt is edge sensitive.
selection
Level
NMIL
bit
NMI
bit