restart_cause() always return zero.

[Jim]

hi,
I try to put the PIC18F722 to sleep, then wake up by WDT or by external Int. After wake up from sleep(), I call restart_cause() to read the cause of waking to find out if it is due to WDT expired or by external interrupts, but the restart_cause() will alway return zero.

I need help please. I have CCS 3.228.
Here is the code:

#fuses HS, PROTECT, PUT, WDT512, NOBROWNOUT, NOLVP, NOCPD, EMCU

#byte OSCCON = 0xFD3
#bit IDLEN = OSCCON.7

void test_power_saving(void)
{
boolean toggle_led;
uint8 resetcause;
//disable_interrupts(GLOBAL);
setup_wdt(WDT_OFF);
sensorctl_sys_led_drv(SENSORCTL_SYS_LED_OFF);
//setup_uart(FALSE);
setup_adc_ports(NO_ANALOGS|VSS_VDD);
setup_adc(ADC_OFF);
//setup_spi(FALSE);
//setup_wdt(WDT_ON);
//setup_timer_0(RTCC_OFF);
//setup_timer_1(T1_DISABLED);
//setup_timer_2(T2_DISABLED,0,1);
//setup_timer_3(T3_DISABLED|T3_DIV_BY_1);
//setup_comparator(NC_NC_NC_NC);
//setup_vref(FALSE);
//setup_low_volt_detect(FALSE);
disable_interrupts( INT_TIMER1 ); // disable Timer1 interrupt


setup_external_memory(EXTMEM_DISABLE);

output_high(PIN_J1);
output_high(PIN_J5);
sensorctl_sys_led_drv(SENSORCTL_SYS_LED_RED);
setup_wdt(WDT_ON);
SETUP_UART(UART_WAKEUP_ON_RDA);

IDLEN = 1;
sleep();
delay_cycles(1);
resetcause = restart_cause();
while (resetcause == WDT_TIMEOUT)
//while(1)
{
if (toggle_led)
{
sensorctl_sys_led_drv(SENSORCTL_SYS_LED_RED);
}
else
{
sensorctl_sys_led_drv(SENSORCTL_SYS_LED_OFF);
}
toggle_led = ~toggle_led;

restart_wdt();
IDLEN = 1;
sleep();
delay_cycles(1);
resetcause = restart_cause();
}
enable_interrupts( INT_TIMER1 ); // disable Timer1 interrupt
enable_interrupts(GLOBAL);
}

[Ttelmah]

It is difficult to follow the posted code (read the sticky thread about how to post code here). However key thing is that you must read 'restart_cause', before calling any of the WDT 'setup' functions.
Basically, the easiest thing is to read it early in the main.

Best Wishes