PICO: Beeper implementation (pwm) (#14493)

src/platform/PICO/mk/RP2350.mk

@@ -403,6 +403,7 @@ MCU_COMMON_SRC = \
             PICO/io_pico.c \
             PICO/persistent.c \
             PICO/pwm_pico.c \
+            PICO/pwm_beeper_pico.c \
             PICO/serial_uart_pico.c \
             PICO/serial_usb_vcp_pico.c \
             PICO/system.c \

src/platform/PICO/pwm_beeper_pico.c

@@ -0,0 +1,83 @@
+/*
+ * This file is part of Betaflight.
+ *
+ * Betaflight is free software. You can redistribute this software
+ * and/or modify this software under the terms of the GNU General
+ * Public License as published by the Free Software Foundation,
+ * either version 3 of the License, or (at your option) any later
+ * version.
+ *
+ * Betaflight is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this software.
+ *
+ * If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stdbool.h>
+#include <stdint.h>
+#include "platform.h"
+
+#if defined(USE_BEEPER) && defined(USE_PWM_OUTPUT)
+
+#include "drivers/io.h"
+#include "drivers/io_impl.h"
+#include "hardware/gpio.h"
+#include "hardware/pwm.h"
+
+static bool beeperConfigured;
+static bool beeperEnabled;
+static int beeperGPIO;
+static uint pwmSlice;
+
+void pwmWriteBeeper(bool on)
+{
+    if (beeperConfigured) {
+        gpio_set_outover(beeperGPIO, on ? GPIO_OVERRIDE_NORMAL : GPIO_OVERRIDE_LOW);
+        pwm_set_enabled(pwmSlice, on);
+        beeperEnabled = on;
+    }
+}
+
+void pwmToggleBeeper(void)
+{
+    pwmWriteBeeper(!beeperEnabled);
+}
+
+void beeperPwmInit(const ioTag_t tag, uint16_t frequency)
+{
+    // frequency should be non-zero when calling beeperPwmInit.
+    IO_t beeperIO = IOGetByTag(tag);
+    if (beeperIO && frequency) {
+        beeperGPIO = IO_GPIOPinIdx(beeperIO);
+        IOInit(beeperIO, OWNER_BEEPER, 0);
+
+        // f = sysclk / div / wrap
+        // Max clock divide is just under 256.
+        uint16_t wrap;
+        uint32_t clock_divide =  (SystemCoreClock / frequency + 0xfffe) / 0xffff; // round up
+        if (clock_divide > 255) {
+            clock_divide  = 255;
+            wrap = 0xffff;
+        } else {
+            wrap = SystemCoreClock / frequency / clock_divide;
+        }
+
+        pwm_config cfg = pwm_get_default_config();
+        pwm_config_set_clkdiv_int(&cfg, clock_divide);
+        pwm_config_set_wrap(&cfg, wrap);
+        pwmSlice = pwm_gpio_to_slice_num(beeperGPIO);
+        pwm_init(pwmSlice, &cfg, false);
+        gpio_set_function(beeperGPIO, GPIO_FUNC_PWM);
+        pwm_set_gpio_level(beeperGPIO, wrap >> 1); // 50% square wave
+        beeperEnabled = false;
+        beeperConfigured = true;
+    }
+}
+
+#endif

src/platform/PICO/target/RP2350B/target.h

@@ -201,6 +201,10 @@
 // Enable 9V if/when we need it (for DVTX?)
 // #define PICO_BEC_9V_ENABLE_PIN PA15
 
+#define USE_BEEPER
+#define BEEPER_PWM_HZ        1971
+#define BEEPER_PIN           PA5
+
 //#undef USE_BARO
 #define USE_BARO_DPS310
 #undef USE_BARO_MS5611