ST72344S4 STMicroelectronics, ST72344S4 Datasheet - Page 54

• Manufacturer Part Number: ST72344S4
• Description: 8-bit MCU
• Manufacturer: STMicroelectronics

Specifications of ST72344S4

• Up To 16 Kbytes Program Memory: single voltage extended Flash (XFlash) with readout and write protection, in-circuit and inapplication programming (ICP and IAP). 10K write/erase cycles guaranteed, data retention
• 256 Bytes Data Eeprom With Readout Protection. 300k Write/erase Cycles Guaranteed, Data Retention: 20 years at 55 °C.
• Clock Sources: crystal/ceramic resonator oscillators, high-accuracy internal RC oscillator or external clock
• 5 Power-saving Modes: Slow, Wait, Halt, Auto-wakeup from Halt and Active-halt
• 16-bit Timer A With: 1 input capture, 1 output compares, external clock input, PWM and pulse generator modes
• 16-bit Timer B With: 2 input captures, 2 output compares, PWM and pulse generator modes

Interrupts
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Table 13.
Figure 20. Interrupt processing flowchart
Servicing pending interrupts
As several interrupts can be pending at the same time, the interrupt to be taken into account
is determined by the following two-step process:
●
●
Figure 21
Figure 21. Priority decision process
the highest software priority interrupt is serviced,
if several interrupts have the same software priority then the interrupt with the highest
hardware priority is serviced first.
RESTORE PC, X, A, CC
describes this decision process.
FROM STACK
RESET
Interrupt software priority
Level 3 (= interrupt disable)
Interrupt software priority levels
Level 0 (main)
Level 1
Level 2
PRIORITY SERVICED
HIGHEST HARDWARE
Same
Doc ID 12321 Rev 5
Y
INSTRUCTION
INTERRUPT
INSTRUCTION
FETCH NEXT
PENDING
EXECUTE
N
“IRET”
N
INTERRUPTS
SOFTWARE
PRIORITY
PENDING
Y
PRIORITY SERVICED
HIGHEST SOFTWARE
THE INTERRUPT
STAYS PENDING
Level
High
Low
Different
Interrupt has the same or a
LOAD I1:0 FROM INTERRUPT SW REG.
LOAD PC FROM INTERRUPT VECTOR
lower software priority
than current one
STACK PC, X, A, CC
ST72344xx ST72345xx
I1
1
0
0
1
TRAP
I1:0
N
I0
0
1
0
1
Y