1 | // Purpose of this example:
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2 | // Explanation of GPIO and INTC modules on AVR32 UC3 chips.
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3 |
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4 | // Hardware requirements:
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5 | // EVK1101 & JTAGICE mkII.
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6 |
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7 | // Application description:
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8 | // LED0 always blinks steadily.
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9 | // Press on PB2 and LED1 is turned on. Release PB2 and LED1 is turned off.
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10 | // Press on PB3 and LED2 is turned on. Release PB3 and LED2 is turned off.
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11 |
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12 |
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13 | //_____ I N C L U D E S ___________________________________________________
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14 |
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15 | #include "compiler.h"
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16 | #include "board.h"
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17 | #include "gpio.h"
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18 | #include "pm.h"
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19 | #include "intc.h"
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20 |
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21 |
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22 |
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23 | //--------------------------------------------------------------------------
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24 | __attribute__((__interrupt__))
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25 | static void int_handler_port1_line0 (void)
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26 | {
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27 | if( gpio_get_pin_interrupt_flag( GPIO_PUSH_BUTTON_0 ) )
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28 | { // PB2 generated the interrupt.
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29 | LED_Toggle( LED1 );
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30 | // Clear the interrupt flag of the pin PB2 is mapped to.
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31 | gpio_clear_pin_interrupt_flag(GPIO_PUSH_BUTTON_0);
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32 | }
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33 | if( gpio_get_pin_interrupt_flag( GPIO_PUSH_BUTTON_1 ) )
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34 | { // PB3 generated the interrupt.
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35 | LED_Toggle( LED2 );
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36 | // Clear the interrupt flag of the pin PB3 is mapped to.
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37 | gpio_clear_pin_interrupt_flag(GPIO_PUSH_BUTTON_1);
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38 | }
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39 | }
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40 | //--------------------------------------------------------------------------
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41 |
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42 |
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43 | //--------------------------------------------------------------------------
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44 | int main(void)
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45 | {
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46 | int i = 0;
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47 | int j = 0;
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48 | int x = 0;
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49 |
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50 |
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51 | // switch to oscillator 0
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52 | pm_switch_to_osc0(&AVR32_PM, FOSC0, OSC0_STARTUP);
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53 |
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54 | // Set all leds initial state.
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55 | LED_Off( LED0 | LED1 | LED2 | LED3 );
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56 |
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57 | // GPIO config
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58 | // configure push button to produce IT on input change
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59 | // NOTE 1: GPIO_PUSH_BUTTON_0 & GPIO_PUSH_BUTTON_1 are defines you can find in
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60 | // evk1101.h under /BOARDS/EVK1101/.
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61 | // See the implementation of gpio_enable_pin_interrupt() in gpio.c under
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62 | // /DRIVERS/GPIO/.
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63 | gpio_enable_pin_interrupt(GPIO_PUSH_BUTTON_0 , GPIO_PIN_CHANGE); // PB2
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64 | gpio_enable_pin_interrupt(GPIO_PUSH_BUTTON_1 , GPIO_PIN_CHANGE); // PB3
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65 | // NOTE 2: GPIO_PUSH_BUTTON_0 & GPIO_PUSH_BUTTON_1 are in the same port.
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66 | // (i.e. port 1, cf section 21.5 of the UC3B0256 datasheet for the computation
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67 | // of a port knowing the pin, and see the evk1101 schematics (or the evk1101.h
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68 | // file) + the section 12.8 of the UC3B0256 datasheet to know the pin mapping
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69 | // of the pushbuttons).
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70 | // Consider GPIO_PUSH_BUTTON_0 as an example: from evk1101.h, we see that
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71 | // GPIO_PUSH_BUTTON_0 is AVR32_PIN_PB02. Open the UC3B0256 datasheet, go to
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72 | // section 12.8, in the array look for pin PB02, we see that it is mapped to
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73 | // GPIO 34. Using section 21.5, the formula to know the port of a pin is:
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74 | // GPIO port = floor((GPIO number) / 32), so for GPIO_PUSH_BUTTON_0 we get:
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75 | // floor(34/32) = 1.
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76 | // Applying the same reasoning for GPIO_PUSH_BUTTON_1 (which is GPIO 35), we
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77 | // find that it belongs to port 1 too.
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78 |
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79 | // NOTE 3: the 32 in the formula 'GPIO port = floor((GPIO number) / 32)'
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80 | // corresponds to the fact that "The pins are managed as 32-bit ports" (see
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81 | // section 21.5 second sentence): i.e. every port holds 32 pins max.
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82 |
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83 | // Interrupts config
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84 | Disable_global_interrupt ();
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85 | INTC_init_interrupts ();
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86 | // register push button handler for PB2 and PB3
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87 | INTC_register_interrupt( &int_handler_port1_line0, AVR32_GPIO_IRQ_0 + (GPIO_PUSH_BUTTON_0/8), INT0);
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88 | INTC_register_interrupt( &int_handler_port1_line0, AVR32_GPIO_IRQ_0 + (GPIO_PUSH_BUTTON_1/8), INT0);
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89 | // NOTE 4: reading section 21.4.7, paragraph 2:
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90 | // "In every port there are four interrupt lines connected to the interrupt
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91 | // controller. Every eigth interrupts in the port are ored together to form an
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92 | // interrupt line."
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93 | // So, for example, for port 1 :
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94 | // GPIO32->GPIO39 : port 1 interrupt line 0 (for int-of-pin32, int-of-pin33,
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95 | // int-of-pin34, int-of-pin35, int-of-pin36, int-of-pin37,
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96 | // int-of-pin38 and int-of-pin39)
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97 | // GPIO40->GPIO47 : port 1 interrupt line 1,
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98 | // GPIO48->GPIO55 : port 1 interrupt line 2,
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99 | // GPIO56->GPIO63 : port 1 interrupt line 3.
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100 | //
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101 | // That is why we use the formula "AVR32_GPIO_IRQ_0 + (GPIO_PUSH_BUTTON_0/8)"
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102 | // to register the PB2; AVR32_GPIO_IRQ_0 is used as the base interrupt line
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103 | // and we add '(GPIO_PUSH_BUTTON_0/8)' to register the corresponding interrupt
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104 | // line.
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105 |
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106 | // NOTE 5: Since PB2 and PB3 are mapped to the GPIO pin GPIO34 and GPIO35, we
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107 | // see that they belong to the same interrupt line. Two consequences in this
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108 | // particular case:
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109 | // 1) it's no use to register both. We left both registration in the code for
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110 | // clarity's sake.
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111 | // 2) we'll discriminate the cause of the interrupt (PB2 or PB3) in the
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112 | // interrupt handler looking at the gpio_port1.ifr register.
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113 | // See int_handler_gpio0() implementation.
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114 |
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115 | Enable_global_interrupt ();
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116 |
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117 | while (TRUE)
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118 | {
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119 | if (i == 100000)
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120 | {
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121 | i = 0;
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122 | if (j == 2)
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123 | {
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124 | x = !x;
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125 | if (x == 0)
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126 | {
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127 | LED_Off (LED0);
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128 | }
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129 | else
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130 | {
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131 | LED_On (LED0);
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132 | }
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133 | j = 0;
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134 | }
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135 | j++;
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136 | }
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137 | i++;
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138 | }
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139 | }
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