Posted on December 13, 2004 at 13:08Hello all,
I am a newbie in microcontroller programming. I am using ST10 microcontroller. My problem is
to determine the speed of a BLDC motor by using three hall sensors.The hall sensors are
connected to ports P8_2,P8_3 and P8_4.My idea is to use only one hall sensor (if possible)
to count the number of pulses in a certain period of time. Each hall sensor remains high for
180 electrical degree and low for the other 180°.My motor has 3 pole-pairs. So, three
electrical cycles are needed for the completion of a mechanical cycle.From this information
I can calculate the speed if I can count the number of pulses.If I am right, for one
mechanical cycle, 6 pulses (3 high, 3 low) can be detected.
I would like to use CAMCOM T0 in counter mode:
//CAPCOM T0 counter mode
void Capcom0Init(void)
{
T01CON = 0x0009;
T0 = 0x0000;
T0REL = 0x0000;
T01CON |= 0x0040;
}
To be true, I got this code from a DC motor control code. I am not sure,how and which port
can be associated with the above code to give T0 values.
The following skeleton (taken from the same source) function calculates the speed:
// Function: GetSpeed
// Purpose: Counts the number of pulses over a given time interval. Uses this value to
calculate the speed
// It uses CAPCOM 16, which is connected to P8_0. CAPCOM 16 is timed with Timer 7.
// Input conditions: P3_0 configured as input (in initialize).
// Destroys: P3_0
// Returns: Speed (m/sec)
float GetSpeed(int ticks,float timeInterval)
{
-----
}
Would be please anybody be kind to clarify my doubts?
Thanks
