topic Re: Doubt with interrupts with MC9s08sh8 in 8-bit Microcontrollers

Doubt with interrupts with MC9s08sh8

glaa91 — Sat, 03 Nov 2012 17:22:08 GMT

Hi, i'm trying to make a program that when i put VCC on one pin of the PortA, the program jump to an Interrupt and turns on a Led on Port B.

The problem is that i can't configure the interrups, and i can't find my error, can anyone help me?? Thanks

it's a simply test program, here it's:

; Include derivative-specific definitions

INCLUDE 'derivative.inc'

; export symbols

;

XDEF _Startup

ABSENTRY _Startup

; variable/data section

;

ORG RAMStart ; Insert your data definition here

ORG ROMStart

_Startup:

LDA SOPT1 ;Deshabilita COP

AND #%00111111

STA SOPT1

LDHX #RAMEnd+1 ; initialize the stack pointer

TXS

MOV #%00000001,PTBDD

MOV #%00000000,PTCDD

MOV #%00000000,PTAES ;SLEW RATE

MOV #%00000000,PTADD ;IN/OUT

MOV #%00111111,PTAPE ;PULL-UP/PULL-DOWN

MOV #%00001111,PTASC ;INTERRUP STATUS AND CONTROL

MOV #%00001111,PTAPS ;HABILITAR/DES INTERRUPCIONES

;MOV #%00001111,PTAES ;

CLI

INICIO:

BCLR 0,PTBD

ini

JMP ini

;**************************************************************

;* spurious - Spurious Interrupt Service Routine. *

;* (unwanted interrupt) *

;**************************************************************

interrup:

NOP

SEI

BSET 0,PTBD

CLI

RTI

spurious: ; placed here so that security value

NOP ; does not change all the time.

RTI

;**************************************************************

;* Interrupt Vectors *

;**************************************************************

ORG $FFD6

DC.W interrup

ORG $FFFA

DC.W spurious ;

DC.W spurious ; SWI

DC.W _Startup ; Reset

Re: Doubt with interrupts with MC9s08sh8

bigmac — Tue, 06 Nov 2012 12:20:28 GMT

Hello,

There are two problems that I can see -

The interrupt edge select register PTAES would seem to have the incorrect setting for what you require. This is not the slew rate register, as your comment indicates! Your settings will give falling edge interrupt operation, with pullups enabled, consistent with a grounded switch contact.
MOV #%00000000,PTAES ;SLEW RATE
The interrupt will need to be acknowledged within your ISR code, to clear the interrupt flag. Otherwise repeated interrupts will occur. Additionally, unless you have a specific need for combined edge and level sensitivity for the interrupt, I might suggest that you set for edge sensitive interrupts only. Level sensitive interrupts will potentially cause multiple interrupts while the input level remains active.

interrup:

NOP ; Unnecessary instruction

SEI ; Unnecessary instruction

MOV #%00000110 ; Acknowledge interrupt

BSET 0,PTBD

CLI ; Unnecessary instruction

RTI

Regards,

Mac

Re: Doubt with interrupts with MC9s08sh8

glaa91 — Tue, 06 Nov 2012 21:36:36 GMT

Hi, thanks you very much for the answer, but i'm still having problems... I can not make that the program works, it is never jumping to the interrupt, can you give me a little more help?

Here is the modified code:

_Startup:

LDA SOPT1 ;Deshabilita COP

AND #%00111111

STA SOPT1

LDHX #RAMEnd+1 ; initialize the stack pointer

TXS

MOV #%00000001,PTBDD

MOV #%00000000,PTCDD

;MOV #%00001111,PTAES ;INTERRUP EDGE

;MOV #%00011111,PTASE ;SLEW RATE

MOV #%00000000,PTADD ;IN/OUT

MOV #%00001111,PTAPE ;PULL-UP/PULL-DOWN

MOV #%00000110,PTASC ;INTERRUP STATUS AND CONTROL

MOV #%00001111,PTAPS ; Enable/disable interrups

CLI

INICIO:

BCLR 0,PTBD

ini

JMP ini

;**************************************************************

;* spurious - Spurious Interrupt Service Routine. *

;* (unwanted interrupt) *

;**************************************************************

interrup:

;NOP

;SEI

MOV #%00000110,PTASC ; Acknowledge interrupt

BSET 0,PTBD

;CLI

;RTI

spurious: ; placed here so that security value

NOP ; does not change all the time.

RTI

;**************************************************************

;* Interrupt Vectors *

;**************************************************************

ORG $FFD6

DC.W interrup

ORG $FFFA

DC.W spurious ;

DC.W spurious ; SWI

DC.W _Startup ; Reset

Thanks,

Gaston.