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|
#include <stdio.h>
#include "pico/stdlib.h"
#include "hardware/uart.h"
#include "hardware/gpio.h"
// UART defines
// By default the stdout UART is `uart0`, so we will use the second one
#define UART_ID uart1
#define BAUD_RATE 115200
// Use pins 4 and 5 for UART1
// Pins can be changed, see the GPIO function select table in the datasheet for information on GPIO assignments
#define UART_TX_PIN 4
#define UART_RX_PIN 5
#define FIRST_GPIO 2
#define BUTTON_GPIO (FIRST_GPIO + 7)
// This array converts a number 0-9 to a bit pattern to send to the GPIOs
int bits[10] = {
0x3f, // 0
0x06, // 1
0x5b, // 2
0x4f, // 3
0x66, // 4
0x6d, // 5
0x7d, // 6
0x07, // 7
0x7f, // 8
0x67 // 9
};
/// \tag::hello_gpio[]
int main()
{
stdio_init_all();
printf("Hello, 7segment - press button to count down!\n");
// We could use gpio_set_dir_out_masked() here
for (int gpio = FIRST_GPIO; gpio < FIRST_GPIO + 7; gpio++)
{
gpio_init(gpio);
gpio_set_dir(gpio, GPIO_OUT);
// Our bitmap above has a bit set where we need an LED on, BUT, we are pulling low to light
// so invert our output
gpio_set_outover(gpio, GPIO_OVERRIDE_INVERT);
}
gpio_init(BUTTON_GPIO);
gpio_set_dir(BUTTON_GPIO, GPIO_IN);
// We are using the button to pull down to 0v when pressed, so ensure that when
// unpressed, it uses internal pull ups. Otherwise when unpressed, the input will
// be floating.
gpio_pull_up(BUTTON_GPIO);
int val = 0;
while (true)
{
// Count upwards or downwards depending on button input
// We are pulling down on switch active, so invert the get to make
// a press count downwards
if (!gpio_get(BUTTON_GPIO))
{
if (val == 9)
{
val = 0;
}
else
{
val++;
}
}
else if (val == 0)
{
val = 9;
}
else
{
val--;
}
// We are starting with GPIO 2, our bitmap starts at bit 0 so shift to start at 2.
int32_t mask = bits[val] << FIRST_GPIO;
// Set all our GPIOs in one go!
// If something else is using GPIO, we might want to use gpio_put_masked()
gpio_set_mask(mask);
sleep_ms(250);
gpio_clr_mask(mask);
uart_init(UART_ID, BAUD_RATE);
// Set the TX and RX pins by using the function select on the GPIO
// Set datasheet for more information on function select
gpio_set_function(UART_TX_PIN, GPIO_FUNC_UART);
gpio_set_function(UART_RX_PIN, GPIO_FUNC_UART);
// Use some the various UART functions to send out data
// In a default system, printf will also output via the default UART
// Send out a string, with CR/LF conversions
uart_puts(UART_ID, "*** UART!\n");
printf("===Hello, world!\n");
sleep_ms(2000);
}
// For more examples of UART use see https://github.com/raspberrypi/pico-examples/tree/master/uart
}
/// \end::hello_gpio[] |
