ST72F324BJ STMICROELECTRONICS [STMicroelectronics], ST72F324BJ Datasheet - Page 24

• Manufacturer Part Number: ST72F324BJ
• Description: 8-bit MCU, 3.8 to 5.5 V operating range with 8 to 32 Kbyte Flash/ROM, 10-bit ADC, 4 timers, SPI, SCI
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

Central processing unit (CPU)
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Table 5.
Table 6.
Table 7.
These two bits are set/cleared by hardware when entering in interrupt. The loaded value is
given by the corresponding bits in the interrupt software priority registers (ISPRx). They can
be also set/cleared by software with the RIM, SIM, IRET, HALT, WFI and PUSH/POP
instructions.
See
Level 0 (main)
Level 1
Level 2
Level 3 (= interrupt disable)
BIt Name
BIt Name
1
0
5
3
Section 7: Interrupts on page 36
I1
I0
C
Z
Zero (Arithmetic Management bit)
Carry/borrow
Software Interrupt Priority 1
Software Interrupt Priority 0
Arithmetic management bits (continued)
Software interrupt bits
Interrupt software priority selection
This bit is set and cleared by hardware. This bit indicates that the result of the last
arithmetic, logical or data manipulation is zero.
0: The result of the last operation is different from zero.
1: The result of the last operation is zero.
This bit is accessed by the JREQ and JRNE test instructions.
This bit is set and cleared by hardware and software. It indicates an overflow or an
underflow has occurred during the last arithmetic operation.
0: No overflow or underflow has occurred.
1: An overflow or underflow has occurred.
This bit is driven by the SCF and RCF instructions and tested by the JRC and JRNC
instructions. It is also affected by the ‘bit test and branch’, shift and rotate instructions.
The combination of the I1 and I0 bits determines the current interrupt software priority
(see
The combination of the I1 and I0 bits determines the current interrupt software priority
(see
Interrupt software priority
Table
Table
7).
7).
for more details.
Function
Function
Level
High
Low
I1
1
1
0
0
ST72324B
I0
0
1
0
1