add_executable(tattlekey
blink.c
+ button.c
config.c
net.c
tattlekey.c
--- /dev/null
+#include "button.h"
+#include "config.h"
+
+#include "hardware/gpio.h"
+
+#include "pico/stdlib.h"
+
+static callback_t button_callback = NULL;
+
+static void respond_to_gpio_interrupt(uint gpio, uint32_t event_mask) {
+ if (gpio == button_pin && event_mask & GPIO_IRQ_EDGE_FALL &&
+ button_callback) {
+ button_callback();
+ }
+}
+
+void begin_listening_for_button_press(callback_t callback) {
+ button_callback = callback;
+
+ gpio_set_pulls(button_pin, 1, 0);
+
+ /* Allow some time for the pull-up to take effect.
+ * I'm not sure if this is necessary.
+ * https://datasheets.raspberrypi.com/pico/raspberry-pi-pico-c-sdk.pdf says
+ * the internal GPIO pull-up resistors are 50k. */
+ sleep_ms(100);
+
+ gpio_set_irq_enabled_with_callback(button_pin, GPIO_IRQ_EDGE_FALL, 1,
+ respond_to_gpio_interrupt);
+}
--- /dev/null
+#ifndef BUTTON_H
+#define BUTTON_H
+
+typedef void (*callback_t)();
+
+void begin_listening_for_button_press(callback_t callback);
+
+#endif
/* For distinguishing reports from multiple tattlekey devices. */
u16_t this_tattler_identity = 1;
+
+/* Which GPIO pin is the button connected to?
+ * The button should span this pin and ground, connecting this pin to ground
+ * when pressed.
+ * https://projects.raspberrypi.org/en/projects/introduction-to-the-pico/10
+ * recommends pins 18, 22, or 28. */
+uint button_pin = 18;
/* For distinguishing reports from multiple tattlekey devices. */
extern u16_t this_tattler_identity;
+/* Which GPIO pin is the button connected to?
+ * The button should span this pin and ground, connecting this pin to ground
+ * when pressed.
+ * https://projects.raspberrypi.org/en/projects/introduction-to-the-pico/10
+ * recommends pins 18, 22, or 28. */
+extern uint button_pin;
+
#endif
#include "pico/stdlib.h"
#include "blink.h"
+#include "button.h"
#include "config.h"
#include "net.h"
+static u16_t seq = 0;
+
+static void button_pressed() {
+ /* TODO: This is interrupt context. We need to get out of interrupt context
+ * quickly; we should not be doing significant work here, & definitely
+ * shouldn't be sleeping here. We signal errors with blinking the LED, which
+ * involves sleeping, so this all has to move. */
+ send_report(seq++, 0);
+ signal(4, 200);
+}
+
+static void wait_forever() {
+ /* pico-examples/gpio/hello_gpio_irq/hello_gpio_irq.c implements wait-forever
+ * as "while (1);", but
+ * https://www.raspberrypi.com/documentation/pico-sdk/high_level.html#gaf469c6d691230e9d1008
+ * says sleeping uses less power, so we sleep. */
+ while (1) {
+ /* https://www.raspberrypi.com/documentation/pico-sdk/hardware.html#rpip7ce2cdc1662dce59296b
+ * says the maximum sleep is 2^32 - 1 microseconds (~71.58 minutes), so we
+ * sleep in chunks. */
+ sleep_ms(1 << 31); /* 35.79 minutes */
+ }
+}
+
int main() {
stdio_init_all();
if (cyw43_arch_init_with_country(CYW43_COUNTRY_USA))
CYW43_AUTH_WPA2_AES_PSK, 10000))
signal_error_by_blinking();
signal(3, 200);
+ begin_listening_for_button_press(button_pressed);
- for (int i = 0;; i++) {
- send_report(i, 0);
- signal(4, 200);
- }
+ wait_forever();
}