96 lines
2.5 KiB
C
96 lines
2.5 KiB
C
/**
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* Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
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*
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* SPDX-License-Identifier: BSD-3-Clause
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*/
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#include <stdio.h>
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#include "pico/stdlib.h"
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#include "hardware/gpio.h"
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/*
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Our 7 Segment display has pins as follows:
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--A--
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F B
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--G--
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E C
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--D--
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By default we are allocating GPIO 2 to A, 3 to B etc.
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So, connect GOIP 2 to pin A on the 7 segment LED display etc. Don't forget
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the appropriate resistors, best to use one for each segment!
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Connect button so that pressing the switch connects the GPIO 9 (default) to
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ground (pull down)
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*/
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#define FIRST_GPIO 2
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#define BUTTON_GPIO (FIRST_GPIO+7)
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// This array converts a number 0-9 to a bit pattern to send to the GPIO's
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int bits[10] = {
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0x3f, // 0
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0x06, // 1
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0x5b, // 2
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0x4f, // 3
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0x66, // 4
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0x6d, // 5
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0x7d, // 6
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0x07, // 7
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0x7f, // 8
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0x67 // 9
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};
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/// \tag::hello_gpio[]
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int main() {
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stdio_init_all();
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printf("Hello, 7segment - press button to count down!\n");
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// We could use gpio_set_dir_out_masked() here
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for (int gpio = FIRST_GPIO; gpio < FIRST_GPIO + 7; gpio++) {
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gpio_init(gpio);
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gpio_set_dir(gpio, GPIO_OUT);
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// Our bitmap above has a bit set where we need an LED on, BUT, we are pulling low to light
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// so invert our output
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gpio_set_outover(gpio, GPIO_OVERRIDE_INVERT);
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}
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gpio_init(BUTTON_GPIO);
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gpio_set_dir(BUTTON_GPIO, GPIO_IN);
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// We are using the button to pull down to 0v when pressed, so ensure that when
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// unpressed, it uses internal pull ups. Otherwise when unpressed, the input will
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// be floating.
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gpio_pull_up(BUTTON_GPIO);
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int val = 0;
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while (true) {
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// Count upwards or downwards depending on button input
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// We are pulling down on switch active, so invert the get to make
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// a press count downwards
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if (!gpio_get(BUTTON_GPIO)) {
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if (val == 9) {
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val = 0;
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} else {
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val++;
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}
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} else if (val == 0) {
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val = 9;
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} else {
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val--;
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}
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// We are starting with GPIO 2, our bitmap starts at bit 0 so shift to start at 2.
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int32_t mask = bits[val] << FIRST_GPIO;
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// Set all our GPIO's in one go!
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// If something else is using GPIO, we might want to use gpio_put_masked()
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gpio_set_mask(mask);
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sleep_ms(250);
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gpio_clr_mask(mask);
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}
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return 0;
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}
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/// \end::hello_gpio[]
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