Digilent PmodHB5 Panduan Referensi - Halaman 3

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PmodHB5: Demo

Resources Used

Timer5 configuration is done using Plib macros in AppInit function. SFRs approach is also provided in

the commented code.

Plib macro used:

OpenTimer5(T5_ON | T5_SOURCE_INT | T5_PS_1_8, 99);

ConfigIntTimer5(T5_INT_ON | T5_INT_PRIOR_7 | T5_INT_SUB_PRIOR_3);

Meaning:

- T5_ON – timer 5 is ON.

- T5_PS_1_8 (Prescaler 1/8): so the frequency is 1/8 of Peripheral bus freq, which is 1/8 of SYSCLK

(65 MHz) = 1 MHz

- Period = 99, so Timer period = (99 + 1) * 1/1MHz = 100 us

- T5_SOURCE_INT : Timer5 triggers interrupt

- T5_INT_ON – T5 interrupt is ON

- T5_INT_PRIOR_7, T5_INT_SUB_PRIOR_3 - timer interrupt priority level 7, subpriority level 3

More information about Timer5 is shown in Timer5Handler.

Functions defined in main.c

void __ISR(_TIMER_5_VECTOR, ipl7) Timer5Handler(void)

Parameters:

none

Interrupt service routine for Timer 5 interrupt. Programmed to execute every 100 us. It is

used to:

1. perform software debouncing of the on-board buttons and detect:

2. to increment the real time counter

3. as a time base for clearing the action LEDs (LD3 and LD2)

4. as a time base for updating the display

int main(void)

Parameters:

none

Performs basic board initialization and then enters the main program loop.

void Display(double dDuty)

Parameters:

dDuty - the applied duty (between -1 and 1), negative values correspond to the

negative direction of motion, while positive numbers correspond to the positive

direction of motion.

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single button situation: when a button should be processed (being pressed or

being kept pressed)

double buttons situation: when a button is released while the other is pressed

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