ST72321AR6 STMicroelectronics, ST72321AR6 Datasheet - Page 187

• Manufacturer Part Number: ST72321AR6
• Description: 8-BIT MCU WITH NESTED INTERRUPTS, FLASH,10-BIT ADC, FIVE TIMERS, SPI, SCI, I2C INTERFACE
• Manufacturer: STMicroelectronics

Specifications of ST72321AR6

• Hdflash Endurance: 100 cycles, data retention
• Clock Sources: crystal/ceramic resonator oscillators, internal RC oscillator, clock security system and bypass for external clock
• Four Power Saving Modes: Halt, Active-Halt,Wait and Slow
• Main Clock Controller With: Real time base, Beep and Clock-out capabilities
• Two 16-bit Timers With: 2 input captures, 2 output compares, external clock input on one timer, PWM and pulse generator modes
• 8-bit Pwm Auto-reload Timer With: 2 input captures, 4 PWM outputs, output compare and time base interrupt, external clock with event detector

TNZ Y
jrne OUT
LD A,sema
edge is detected
CP A,#01
jrne OUT
call call_routine; call the interrupt routine
OUT:LD A,#00
LD sema,A
.call_routine
PUSH A
PUSH X
PUSH CC
.ext1_rt
LD A,#00
LD sema,A
IRET
Case 2: Writing to PxOR or PxDDR with Global In-
terrupts Disabled:
SIM
LD A,PFDR
AND A,#$02
LD X,A
PxOR/PxDDR
LD A,#$90
LD PFDDR,A; Write into PFDDR
LD A,#$ff
LD PFOR,A
LD A,PFDR
AND A,#$02
LD Y,A
PxDDR
LD A,X
cp A,#$02
jrne OUT
TNZ Y
jrne OUT
LD A,#$01
LD sema,A ; set the semaphore to '1' if edge is
detected
RIM
LD A,sema ; check the semaphore status
CP A,#$01
; set the interrupt mask
; store the level before writing to
; store the level after writing to PxOR/
; check for falling edge
; reset the interrupt mask
; check the semaphore status if
; entry to call_routine
; entry to interrupt routine
; Write to PFOR
jrne OUT
call call_routine; call the interrupt routine
RIM
OUT:
JP while_loop
.call_routine ; entry to call_routine
PUSH A
PUSH X
PUSH CC
.ext1_rt
LD A,#$00
LD sema,A
IRET
15.1.6
interrupt routine
When an active interrupt request occurs at the
same time as the related flag is being cleared, an
unwanted reset may occur.
Note: clearing the related interrupt mask will not
generate an unwanted reset
Concurrent interrupt context
The symptom does not occur when the interrupts
are handled normally, i.e.
when:
– The interrupt flag is cleared within its own inter-
– The interrupt flag is cleared within any interrupt
– The interrupt flag is cleared in any part of the
If these conditions are not met, the symptom can
be avoided by implementing the following se-
quence:
Perform SIM and RIM operation before and after
resetting an active interrupt request.
Example:
Nested interrupt context:
The symptom does not occur when the interrupts
are handled normally, i.e.
when:
– The interrupt flag is cleared within its own inter-
rupt routine
routine
code while this interrupt is disabled
rupt routine
SIM
reset interrupt flag
RIM
ST72321Rx ST72321ARx ST72321Jx
Clearing
RIM
; entry to interrupt routine
active
interrupts
outside
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