Posted on October 28, 2005 at 09:58Hi,
Im connecting a voltage detector to the MCU's GPIO pin using open drain configuration. when it falls below a threshold voltage, the output pin of the voltage detected will be ground, else if above the treshold voltage will be in high impedance. The GPIO is defined as
GPIO_Config(GPIO1, 0x0100, GPIO_IPUPD_WP);
GPIO_BitWrite(GPIO1, 8, 0x01);
while(1)
{
low_battery_current_status = GPIO_BitRead (GPIO1, 0x08);
if((low_battery_latch_status == RESET) && (low_battery_current_status == 0x00))
{
low_battery_latch_status == SET;
....
....
}
else
{
if((low_battery_latch_status == SET) && (low_battery_current_status == 0x01))
{
low_battery_latch_status = RESET;
...
...
}
}
My problem is once I've detected the pin to low, i cant detect it to be high.If I stopped after excuting the statement GPIO_BitWrite(GPIO1, 8, 0x01); and manipulate the treshold voltage, the voltage at the pin shows exactly what it should be; 3.3V when above treshold voltage and 0V when below treshold voltage whereas if I run the program, once it goes from 3.3V to 0V, it cant go up to 3.3V...I m suspecting the that mayb the function GPIO_BitRead (GPIO1, 0x08) might have someting to do with it.
Pls advise.
Rgds,
ongth60
