ST72F324LJ2T5 datasheet(151/154 Pages) STMICROELECTRONICS

151 / 154 page

ST72324Lxx

151/154

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 In-

terrupts Disabled:

SIM ; set the interrupt mask

LD A,PFDR

AND A,#$02

LD 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/PxD-

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 de-

tected

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

OUT:RIM

JP while_loop

.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

15.2 ROM DEVICES ONLY

15.2.1 I/O Port A and F Configuration

When using an external quartz crystal or ceramic

resonator, the fOSC2 clock may be disturbed be-

cause the device goes into reserved mode control-

led by Port A and F.

This happens with either one of the following con-

figurations:

PA3=0, PF4=1, PF1=0 when the PLL option is dis-

abled and PF0 is toggling

PA3=0, PF4=1, PF1=0, PF0=1 when the PLL op-

tion is enabled

This is detailed in the following table:

As a consequence, for cycle-accurate operations,

these configurations are prohibited in either input

or output mode.

Workaround:

To avoid this occurring, it is recommended to con-

nect one of these pins to GND (PF4 or PF0) or

VDD (PA3 or PF1).

PLL PA3 PF4 PF1 PF0 Clock Disturbance

OFF

Tog-

gling

Max. 2 clock cycles

lost at each rising or

falling edge of PF0

Max. 1 clock cycle

lost out of every 16

ST72F324LJ2T5 Datasheet(PDF) 151 Page - STMicroelectronics

ST72F324LJ2T5 Datasheet(HTML) 151 Page - STMicroelectronics

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL