ST72344S2 datasheet(240/247 Pages) STMICROELECTRONICS

240 / 247 page

Known limitations

ST72344xx, ST2345xx

240/247

Doc ID 12321 Rev 6

LD Y,A; store the level after writing to PxOR/PxDDR

LD A,X; check for falling edge

cp A,#02

jrne OUT

TNZ Y

jrne OUT

LD A,sema; check the semaphore status if edge is detected

CP A,#01

jrne OUT

call call_routine; call the interrupt routine

OUT:LD A,#00

LD sema,A

.call_routine; entry to call_routine

PUSH A

PUSH X

PUSH CC

.ext1_rt; entry to interrupt routine

LD A,#00

LD sema,A

IRET

Case 2: Writing to PxOR or PxDDR with global interrupts disabled:

SIM; set the interrupt mask

LD A,PFDR

AND A,#$02

X,A; store the level before writing to PxOR/PxDDR

LD A,#$90

LD PFDDR,A; Write into PFDDR

LD A,#$ff

LD PFOR,A; Write to PFOR

LD A,PFDR

AND A,#$02

LD Y,A; store the level after writing to PxOR/PxDDR

LD A,X; check for falling edge

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; reset the interrupt mask

LD A,sema; check the semaphore status

CP A,#$01

jrne OUT

call call_routine; call the interrupt routine

RIM

ST72344S2 Datasheet(PDF) 240 Page - STMicroelectronics

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