MC9S08QE16 slow timer startup

June — Tue, 06 May 2014 09:16:20 GMT

Hi,

I'm using MC9S08QE16 microprocessor. I noticed that upon startup and initialization, the timer interrupts take a long time to be up and running. Based on my measurements, Timer2 takes approximately 4s and Timer3 takes approximately 8s to be up and running.

In the attached screen capture, I can see that all initialization routines completed within 435ms upon power up. However, the first Timer2 interrupt (WDI timer on the screen capture) fired 4.435s later. I appreciate some advice on what is causing the slow startup of the timers. Thanks!

The initialization routines as follows:

void main(void) {

//Put this into initialisation if you want

MCU_init();

PTCD_PTCD6 ^= 1;

Timer1_Module_Init();

PTCD_PTCD6 ^= 1;

Timer2_Module_Init();

PTCD_PTCD6 ^= 1;

Timer3_Module_Init();

PTCD_PTCD6 ^= 1;

Power_Supply_Detect();

PTCD_PTCD6 ^= 1;

RelayInfo_Init();

State_Machine_Init();

KBI_Module_Init();

ResetTimeoutTimer();

PTCD_PTCD6 ^= 1;

EnableInterrupts

for (;;)

{

}

The following are the MCU init and Timer module init routines:

void MCU_init(void)

{

/* Select "Generate Code" to create initialization code here */

SOPT1 = 0x23; // Disable COP, enable STOP,BKGD,RESET

SOPT2 = 0x90; // TPM2CH2 on PTC1, TPM1CH2 on PTC0

SPMSC1 = 0x00; // Disable LVD

SPMSC2 = 0x80;

SPMSC3 = 0x00; // Disable LVWIE, low trip points

SCGC1 = 0xE8u; /* Enable bus clock to TPM1,2,3. Bit 3 must be 1 per datasheet. */

SCGC2 = 0x32u; /* Enable bus clock to IRQ and KBI. Bit 1 must be 1 per datasheet. */

ICSC1 = 0x00; /* FLL selected */

ICSC2 = 0xCF; /* Bus frequency diver = 8 */

ICSSC = 0x00; /* DCO low range selected */

PTASE = 0x00u;

PTADS = 0x00u;

PTAPE = 0x00u;

PTADD = (uint8)0xC0u;

PTBDD = (uint8)0x10u;

PTCDD = (uint8)0xCFu;

PTDDD = (uint8)0xFFu;

PTEDD = (uint8)0x80u;

}

void

Timer1_Module_Init( void )

{

/* Channel 0 for state machine */

TPM1SC = 0x0Eu; /* bus clock, prescaler = 64 */

TPM1C0SC = 0x10u; /* don't enable channel 0 interrupt first, software output compare only */

TPM1C0V = 205u; /* 12.5ms */

/* Channel 1 for 2ms delay before re-enabling KBI to prevent glitches */

TPM1C1SC = 0x10u; /* don't enable channel 1 interrupt first, software output compare only */

TPM1C1V = 99; /* 6ms */

/* Channel 2 for 1sec communication timeout */

TPM1C2SC = 0x10u; /* don't enable channel 2 interrupt first, software output compare only */

TPM1C2V = 16384; /* 1sec */

}

/*++

**==============================================================================

** Initialize Timer 2 Module's registers.

** This timer is in charge of just counting for the time outs and setting

** flags along the way.

** Called with : nothing

** Returns : nothing

** Global variables : TPM2 registers

**==============================================================================

*--*/

void

Timer2_Module_Init( void )

{

TPM2SC = 0x00u;

TPM2C2SC = 0x00u;

TPM2C2V = 164u; /* 10ms */

TPM2CNT = 0x00u; /* clear the counter */

TPM2SC = 0x0Eu; /* bus clock, prescaler = 64 */

TPM2C2SC = 0x50u; /* enable channel 2 interrupt, software output compare only */

}

/*++

**==============================================================================

** Initialize Timer 3 Channel 5 Module's registers.

** This timer is in charge of LED time division

** Called with : nothing

** Returns : nothing

** Global variables : TPM3 registers

**==============================================================================

*--*/

void

Timer3_Module_Init( void )

{

TPM3SC = 0x00u;

TPM3C5SC = 0x00u;

TPM3C5V = 41u; /* approximately 4ms */

TPM3CNT = 0x00u; /* clear the counter */

TPM3SC = 0x0Fu; /* bus clock, prescaler = 128 */

TPM3C5SC = 0x50u; /* enable channel 5 interrupt, software output compare only */

}

Re: MC9S08QE16 slow timer startup

iansmusical — Tue, 06 May 2014 12:16:01 GMT

Hi June,

The obvious answer is to check that the bus clock and TPM prescalers are what you'd expect them to be for the timeouts required.

Thanks,

Ian

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MC9S08QE16 slow timer startup

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