Port A : Pin out problem PTA5/IRQ/TCLK/RESET

RChris — Sat, 09 Jan 2010 00:01:47 GMT

Hi,

I use the freescale processor MC9S08QG4 (HCS08 family) and i worked on a program that use the pin PTA5/IRQ/TCLK/RESET as an input.

In the documentation i found that this pin has several functions and i try to deactivate them but i still unable to used PTA5 as an input.

In the function that make the initialisation, i set the Port A and B pins and i set the SCI module. I use the following code to init the chip.

void MCU_init(void)
{
   /* ### MC9S08QG8_16 "Cpu" init code ... */
   /* PE initialization code after reset */

/* SOPT1: COPE=0,COPT=1,STOPE=0,BKGDPE=0,RSTPE=0 */
//SOPT1 = 0x50;
SOPT1 = 0x52; // Debug
/* SPMSC1: LVDF=0,LVDACK=0,LVDIE=0,LVDRE=1,LVDSE=1,LVDE=1,BGBE=0 */
SPMSC1 = 0x1C;
/* SPMSC2: PDF=0,PPDF=0,PPDACK=0,PDC=0,PPDC=0 */
SPMSC2 = 0x00;
/* SPMSC3: LVDV=0,LVWV=0 */
SPMSC3 &= (unsigned char)~0x30;
/* System clock initialization */
ICSTRM = *(unsigned char*far)0xFFAF; /* Initialize ICSTRM register from a non volatile memory */
ICSSC = *(unsigned char*far)0xFFAE; /* Initialize ICSSC register from a non volatile memory */
/* ICSC1: CLKS=0,RDIV=0,IREFS=1,IRCLKEN=0,IREFSTEN=0 */
ICSC1 = 0x04;                        /* Initialization of the ICS control register 1 */
/* ICSC2: BDIV=0,RANGE=0,HGO=0,LP=0,EREFS=0,ERCLKEN=0,EREFSTEN=0 */
ICSC2 = 0x00;                        /* Initialization of the ICS control register 2 */
/* Common initialization of the CPU registers */
/* PTASE: PTASE5=0,PTASE4=0,PTASE3=0,PTASE2=0,PTASE1=0,PTASE0=0 */
PTASE &= (unsigned char)~0x3F;
/* PTBSE: PTBSE7=0,PTBSE6=0,PTBSE5=0,PTBSE4=0,PTBSE3=0,PTBSE2=0,PTBSE1=0,PTBSE0=0 */
PTBSE = 0x00;
/* PTADS: PTADS5=0,PTADS4=0,PTADS3=0,PTADS2=0,PTADS1=0,PTADS0=0 */
PTADS = 0x00;
/* PTBDS: PTBDS7=0,PTBDS6=0,PTBDS5=0,PTBDS4=0,PTBDS3=0,PTBDS2=0,PTBDS1=0,PTBDS0=0 */
PTBDS = 0x00;
/* ### Init_GPIO init code */
/* PTADD: PTADD5=0,PTADD4=1,PTADD3=0,PTADD2=0 */
PTADD = (PTADD & (unsigned char)~0x2C) | (unsigned char)0x10;
/* ### Init_GPIO init code */
/* PTBDD: PTBDD5=0,PTBDD4=0,PTBDD3=1,PTBDD2=0 */
PTBDD = (PTBDD & (unsigned char)~0x34) | (unsigned char)0x08;

PTAD &= ((1<<4) && (1<<5));
PTBD = 0x00;

/* ### Init_SCI init code */
/* SCIC2: TIE=0,TCIE=0,RIE=0,ILIE=0,TE=0,RE=0,RWU=0,SBK=0 */
SCIC2 = 0x00;                        /* Disable the SCI module */
(void)(SCIS1 == 0);                  /* Dummy read of the SCIS1 registr to clear flags */
(void)(SCID == 0);                   /* Dummy read of the SCID registr to clear flags */
/* SCIBD: SBR12=0,SBR11=0,SBR10=0,SBR9=0,SBR8=0,SBR7=0,SBR6=0,SBR5=1,SBR4=1,SBR3=0,SBR2=1,SBR1=0,SBR0=0 */
SCIBD = 0x34;
/* SCIC1: LOOPS=0,SCISWAI=0,Rsrc=0,M=0,WAKE=0,ILT=0,PE=0,PT=0 */
SCIC1 = 0x00;
/* SCIC2: TIE=0,TCIE=0,RIE=0,ILIE=0,TE=1,RE=1,RWU=0,SBK=0 */
SCIC2 = 0x0C;
/* SCIC3: R8=0,T8=0,TXDIR=0,TXINV=0,ORIE=0,NEIE=0,FEIE=0,PEIE=0 */
SCIC3 = 0x00;
/* SCIS2: BRK13=0,RAF=0 */
SCIS2 = 0x00;

} /*MCU_init*/

The main function is also simple, i make a loop and i toggle 2 pin on the Port A, PTA4 and PTA5 and 1 pin on Port B (PTB3).

This program doesn't not work for PTA5 but work well for the other pins (PTA4 and PTB3). I use an

oscilloscope to confirm that there is nothing on the PTA5 pin.

void main(void)
{
char hello_word[] = "Hello world\n\0";
short counter = 0;
unsigned char check = 0;

/* Init Register */
MCU_init();

EnableInterrupts; /* enable interrupts */
/* include your code here */

for(;
{
    __RESET_WATCHDOG(); /* feeds the dog */

      if(!counter)
      {
        PTAD_PTAD5   = ~PTAD_PTAD5;
        PTBD_PTBD3   = ~PTBD_PTBD3;
        PTAD_PTAD4   = ~PTAD_PTAD4;

        send2serial( hello_word );

        check = PTAD_PTAD5;

        if(! check)
        {
           send2serial( "PTA5=0\n\0" );
        }

        check = PTBD_PTBD3;

        if(! check)
        {
           send2serial( "PTB3=0\n\0" );
        }

        check = PTAD_PTAD4;

        if(! check)
        {
           send2serial( "PTA4=0\n\0" );
        }

      }

      counter = (counter + 1) % 10000;

} /* loop forever */
/* please make sure that you never leave main */
}

Re: Port A : Pin out problem PTA5/IRQ/TCLK/RESET (Solved)

RChris — Thu, 14 Jan 2010 16:35:37 GMT

Hi,

I found the reason why it is not possible to use the pin PTA5 as a output, it is mentionned in the datascheet of the processor MC9S08QG4 (HCS08 family) in the section "2.2 Recommended System Connections".

There is a diagram (Figure 2-4. Basic System Connections) that explains that the pin PTA5 could be used only as an input.

The problem is solved.

topic Re: Port A : Pin out problem PTA5/IRQ/TCLK/RESET (Solved) in 8-bit Microcontrollers

Port A : Pin out problem PTA5/IRQ/TCLK/RESET

Re: Port A : Pin out problem PTA5/IRQ/TCLK/RESET (Solved)