Unstability problem

AntE — Fri, 04 Dec 2009 15:59:00 GMT

Hello, Im making an application with a HCS08QG8, and the code runs ok, but the broblem is this: when I connect the circuit to power, the display LCD (16x2) Im using dont show the proper message (only the first row with the full squares it normally does when you power it without sending data) and it stays in this way, if I reset the uC it stays the same way (reset enabled), only works sometimes when I repeatedly power on and off, and sometimes when I move the uC directly in the circuit (it has a base so it isnt directly welded, to program and test). Once it starts to run it works well, if I reset it starts to work again, BUT if I power off and on again (without moving the uC) it doesn´t work again. I hope someone can help me.

This is the initialization code:

MCU_init:
; ### MC9S08QG8_8 "Cpu" init code ...

        LDA     #$FC    ; PTB0 y PTB1 como entradas (sensores de freno y liquido respec.)
        CLR     PTBD    ; PTB2=0,PTB3=0,PTB4,..PTB7=0
        STA     PTBDD   ; RS, EN,   D0,..,D3 =SALIDA

        LDA     #$10    ; PTA0, PTA1, PTA2, PTA3 y PTA5 como entradas
        CLR     PTAD    ; PTA4 como salida (activacion de sensores de reversa)
        STA     PTADD   ; PTA0 = entrada sen. reversa, PTA1 = entrada de selector de reversa (555)
                        ; PTA3 y PTA2 son selectores de MODO1/2
        MOV     #0,PTAD

        LDHX    #$4000000/(16*9600)
        STHX    SCIBDH
        MOV     #$0C,SCIC2

; Common initialization of the write once registers
        ; SOPT1: COPE=0,COPT=1,STOPE=0,BKGDPE=1,RSTPE=1
        LDA     #$51 ;#$D1   ;#$53
        STA     SOPT1
        ; SPMSC1: LVDF=0,LVDACK=0,LVDIE=0,LVDRE=1,LVDSE=1,LVDE=1,BGBE=0
        LDA     #$1C
        STA     SPMSC1
        ; SPMSC2: PDF=0,PPDF=0,PPDACK=0,PDC=0,PPDC=0
        CLRA
        STA     SPMSC2
        ; SPMSC3: LVDV=0,LVWV=0
        LDA     SPMSC3
        AND     #$CF
        STA     SPMSC3
; System clock initialization
        ; ICSTRM: Initialize internal clock trim from a non volatile memory
        LDA     $FFAF
        STA     ICSTRM
        ; ICSSC: Initialize internal clock trim from a non volatile memory
        LDA     $FFAE
        STA     ICSSC
        ; ICSC1: CLKS=0,RDIV=0,IREFS=1,IRCLKEN=0,IREFSTEN=0
        MOV     #$04,ICSC1             ; Initialization of the ICS control register 1
        ; ICSC2: BDIV=1,RANGE=0,HGO=0,LP=0,EREFS=0,ERCLKEN=0,EREFSTEN=0
        MOV     #$40,ICSC2             ; Initialization of the ICS control register 2
; Common initialization of the CPU registers
        ; PTASE: PTASE5=1,PTASE4=1,PTASE3=1,PTASE2=1,PTASE1=1,PTASE0=1
        LDA     PTASE
        ORA     #$3F
        STA     PTASE
        ; PTBSE: PTBSE7=1,PTBSE6=1,PTBSE5=1,PTBSE4=1,PTBSE3=1,PTBSE2=1,PTBSE1=1,PTBSE0=1
        LDA     #$FF
        STA     PTBSE
        ; PTADS: PTADS5=0,PTADS4=0,PTADS3=0,PTADS2=0,PTADS1=0,PTADS0=0
        CLRA
        STA     PTADS
        ; PTBDS: PTBDS7=0,PTBDS6=0,PTBDS5=0,PTBDS4=0,PTBDS3=0,PTBDS2=0,PTBDS1=0,PTBDS0=0
        CLRA
        STA     PTBDS

;       CLI                            ; Enable interrupts
        RTS

Re: Instability problem

tonyp — Fri, 04 Dec 2009 17:33:34 GMT

It sounds like you have inadequate/wrong delays in your LCD initialization code (which you could have posted instead, since the problem is LCD related).

By the way, the baud initialization is certainly incorrect because of the unneeded hex symbol.

LDHX #$4000000/(16*9600)

Maybe you have a similar typing error in your [LCD] delays, which would throw them off.

Re: Unstability problem

jag — Fri, 04 Dec 2009 18:42:38 GMT

Hi,

it seems you have an LCD with a KS0066 driver. Is it correct?

You have to wait more than 30 msec after the Vdd rise to 4.5V.

Check the datasheet. Timing is very important with the KS0066.

Bye Jack

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