Hi all,

I have a simple test, a 555 timer produces pusles (as I can see that with my oscilloscope). I want to count these pulses. I want to use Timer3.

I have this code, but I cannot see why it isn’t working.

Which bit(s) needs to be flipped in order for it to work?

Many thanks in advance.

```
public enum Bits
{
BIT0 = 1 << 0,
BIT1 = 1 << 1,
BIT2 = 1 << 2,
BIT3 = 1 << 3,
BIT4 = 1 << 4,
BIT5 = 1 << 5,
BIT6 = 1 << 6,
BIT7 = 1 << 7,
BIT8 = 1 << 8,
BIT9 = 1 << 9,
BIT10 = 1 << 10,
BIT11 = 1 << 11,
BIT12 = 1 << 12,
BIT13 = 1 << 13,
BIT14 = 1 << 14,
BIT15 = 1 << 15,
BIT16 = 1 << 16,
BIT17 = 1 << 17,
BIT18 = 1 << 18,
BIT19 = 1 << 19,
BIT20 = 1 << 20,
BIT21 = 1 << 21,
BIT22 = 1 << 22,
BIT23 = 1 << 23,
BIT24 = 1 << 24,
BIT25 = 1 << 25,
BIT26 = 1 << 26,
BIT27 = 1 << 27,
BIT28 = 1 << 28,
BIT29 = 1 << 29,
BIT30 = 1 << 30,
BIT31 = 1 << 31,
}
//Turn on the power of timer 3
Register PCONP1 = new Register(0xE01FC0C4);
PCONP1.SetBits((uint)Bits.BIT23);
if ((PCONP1.Read() & (uint)Bits.BIT23) != (uint)Bits.BIT23)
{
Debug.Print("Failed to turn on power of timer 3");
}
//23.6.2 The Timer Control Register (TCR) is used to control the operation of the Timer/Counter.
Register TimerControlRegister3 = new Register(0xE0074004);
TimerControlRegister3.Write(1);
//TimerControlRegister3.SetBits((uint)Bits.BIT1); //1: Timer Counter and Prescale Counter are enabled for counting. 0: disabled
//Hold counter in reset: TimerControlRegister3.SetBits(1 << 1);
//Release counter from reset: TimerControlRegister3.ClearBits(1 << 1);
//23.6.3 The Count Control Register (CTCR) is used to select between Timer and Counter mode,
//and in Counter mode to select the pin and edge(s) for counting.
//NOTE: The frequency of the CAP input can not exceed one quarter of the PCLK clock, meaning 78MHz clock / 4 = 19MH resolution counter. Thats enough to count < 200KHz.
Register CountControlRegister3 = new Register(0xE0074070);
//0:1 value 01: Counter Mode: TC is incremented on rising edges on the CAP input
CountControlRegister3.SetBits((uint)Bits.BIT0);
CountControlRegister3.ClearBits((uint)Bits.BIT1 | (uint)Bits.BIT2 | (uint)Bits.BIT3); // Selects CAP3.0 for TIMER3, this is P0.23
//Becase CountControlRegister3 uses CAP3.0, the pin function must be selected to be CAP3.0 See tabl 107 chapter 9.5.2.1
Register PinFunctionSelectRegister1 = new Register(0xE002C004);
PinFunctionSelectRegister1.SetBits((uint)(Bits.BIT14 | Bits.BIT15)); //Give Pin0.23/AD0.0 the function of CAP3.0 That is Timer 3 capture mode.
//Set counter to 0
Register PrescaleRegister3 = new Register(0xE007400C);
PrescaleRegister3.Write(0);
//Match Control Register are not used, make sure all is off
Register MatchControlRegister3 = new Register(0xE0074014);
MatchControlRegister3.ClearBits((uint)(Bits.BIT0 |
Bits.BIT1 |
Bits.BIT2 |
Bits.BIT3 |
Bits.BIT4 |
Bits.BIT5 |
Bits.BIT6 |
Bits.BIT7 |
Bits.BIT8 |
Bits.BIT9 |
Bits.BIT10
)
);
//Not used in counter mode so set to 0
Register CaptureControlRegister3 = new Register(0xE0074028);
CaptureControlRegister3.ClearBits((uint)(Bits.BIT0 | Bits.BIT1 | Bits.BIT2));
TimerControlRegister3.SetBits((uint)Bits.BIT1);
TimerControlRegister3.ClearBits((uint)Bits.BIT1);
//The 32-bit Timer Counter register is incremented when the prescale counter reaches its terminal count.
//Used for reading the count
Register TimerCounterRegister3 = new Register(0xE0074008);
//Read the value of the counter
uint Counts = 0;
while (true)
{
Counts = TimerCounterRegister3.Read();
Debug.Print(Counts.ToString());
Thread.Sleep(1000);
}
```