ST72324xx-Auto
Interrupts
7.6
External interrupts
7.6.1 I/O port interrupt sensitivity
The external interrupt sensitivity is controlled by the IPA, IPB and ISxx bits of the EICR
register (Figure 20). This control allows up to four fully independent external interrupt source
sensitivities.
Each external interrupt source can be generated on four (or five) different events on the pin:
● Falling edge
● Rising edge
● Falling and rising edge
● Falling edge and low level
t(s) ● Rising edge and high level (only for ei0 and ei2)
To guarantee correct functionality, the sensitivity bits in the EICR register can be modified
uc only when the I1 and I0 bits of the CC register are both set to 1 (level 3). This means that
d interrupts must be disabled before changing sensitivity.
ro The pending interrupts are cleared by writing a different value in the ISx[1:0], IPA or IPB bits
P of the EICR.
lete Figure 20. External interrupt control bits
so Port A3 interrupt
Ob PAOR.3
PADDR.3
- PA3
t(s) IPA BIT
c Port F [2:0] interrupts
du PFOR.2
roPFDDR.2
PPF2
EICR
IS20 IS21
Sensitivity
control
EICR
IS20 IS21
Sensitivity
PF2
control
PF1
PF0
ei0 interrupt source
ei1 interrupt source
olete Port B [3:0] interrupts
bs PBOR.3
PBDDR.3
O PB3
EICR
IS10 IS11
Sensitivity
PB3
control
PB2
ei2 interrupt source
PB1
PB0
IPB BIT
Port B4 interrupt
PBOR.4
PBDDR.4
PB4
EICR
IS10 IS11
Sensitivity
control
ei3 interrupt source
Doc ID 13841 Rev 1
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