add lipo shim reading

CMakeLists.txt

@@ -54,6 +54,7 @@ target_sources(gadget PUBLIC
     src/fat_disk.c
     src/debug.c
     src/buttons.c
+    src/lipo.c
 
     ${CMAKE_CURRENT_BINARY_DIR}/fatfs/ff.c
     ${CMAKE_CURRENT_BINARY_DIR}/fatfs/ffunicode.c
@@ -97,6 +98,7 @@ target_link_libraries(gadget
     tinyusb_device
     tinyusb_board
     hardware_spi
+    hardware_adc
     pico_btstack_ble
     pico_btstack_cyw43
     pico_cyw43_arch_threadsafe_background

README.md

@@ -2,7 +2,7 @@
 
 For use with Raspberry Pi Pico W boards with the [Waveshare Pico LCD 1.3](https://www.waveshare.com/wiki/Pico-LCD-1.3) and the [Pimoroni Pico Lipo Shim](https://shop.pimoroni.com/products/pico-lipo-shim).
 
-Adapted from the [tinyusb-cdc-example](https://github.com/hathach/tinyusb/blob/master/examples/device/cdc_msc/src/main.c), [standalone client example](https://github.com/raspberrypi/pico-examples/blob/master/pico_w/bt/standalone/client.c) and my [Trackball firmware](https://git.xythobuz.de/thomas/Trackball).
+Adapted from the [tinyusb-cdc-example](https://github.com/hathach/tinyusb/blob/master/examples/device/cdc_msc/src/main.c), [adc example](https://github.com/raspberrypi/pico-examples/tree/master/adc/read_vsys), [standalone client example](https://github.com/raspberrypi/pico-examples/blob/master/pico_w/bt/standalone/client.c) and my [Trackball firmware](https://git.xythobuz.de/thomas/Trackball).
 
 ## Quick Start
 

include/lipo.h

@@ -0,0 +1,28 @@
+/*
+ * lipo.h
+ *
+ * https://github.com/raspberrypi/pico-examples/blob/master/adc/read_vsys/power_status.c
+ *
+ * Copyright (c) 2023 Thomas Buck (thomas@xythobuz.de)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it 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.
+ *
+ * This program 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.
+ *
+ * See <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __LIPO_H__
+#define __LIPO_H__
+
+bool lipo_charging(void);
+float lipo_voltage(void);
+float lipo_percentage(float voltage);
+
+#endif // __LIPO_H__

src/console.c

@@ -28,6 +28,7 @@
 #include "usb_msc.h"
 #include "debug.h"
 #include "console.h"
+#include "lipo.h"
 
 #define CNSL_BUFF_SIZE 1024
 #define CNSL_REPEAT_MS 500
@@ -65,13 +66,13 @@ static void cnsl_interpret(const char *line) {
     } else if ((strcmp(line, "help") == 0)
             || (strcmp(line, "h") == 0)
             || (strcmp(line, "?") == 0)) {
-        println("Trackball Firmware Usage:");
+        println("VolcanoRC Firmware Usage:");
         println("  reset - reset back into this firmware");
         println("   \\x18 - reset to bootloader");
         println(" repeat - repeat last command every %d milliseconds", CNSL_REPEAT_MS);
         println("   help - print this message");
         println("  mount - make mass storage medium (un)available");
-        //println("    foo - bar");
+        println("  power - show Lipo battery status");
         println("Press Enter with no input to repeat last command.");
         println("Use repeat to continuously execute last command.");
         println("Stop this by calling repeat again.");
@@ -83,6 +84,11 @@ static void cnsl_interpret(const char *line) {
                 state ? "mounted" : "unmounted",
                 state ? "Unplugging" : "Plugging in");
         msc_set_medium_available(!state);
+    } else if (strcmp(line, "power") == 0) {
+        float volt = lipo_voltage();
+        println("Battery: %.2fV = %.1f%% @ %s",
+                volt, lipo_percentage(volt),
+                lipo_charging() ? "charging" : "draining");
     } else {
         println("unknown command \"%s\"", line);
     }

src/lipo.c

@@ -0,0 +1,105 @@
+/*
+ * lipo.c
+ *
+ * https://github.com/raspberrypi/pico-examples/blob/master/adc/read_vsys/power_status.c
+ *
+ * Copyright (c) 2023 Thomas Buck (thomas@xythobuz.de)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it 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.
+ *
+ * This program 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.
+ *
+ * See <http://www.gnu.org/licenses/>.
+ */
+
+#include "stdbool.h"
+#include "hardware/adc.h"
+
+#include "config.h"
+#include "lipo.h"
+
+#if CYW43_USES_VSYS_PIN
+#include "pico/cyw43_arch.h"
+#endif
+
+#ifndef PICO_POWER_SAMPLE_COUNT
+#define PICO_POWER_SAMPLE_COUNT 3
+#endif
+
+// Pin used for ADC 0
+#define PICO_FIRST_ADC_PIN 26
+
+static const float full_battery = 4.1f;
+static const float empty_battery = 3.2f;
+
+bool lipo_charging(void) {
+#if defined CYW43_WL_GPIO_VBUS_PIN
+    return cyw43_arch_gpio_get(CYW43_WL_GPIO_VBUS_PIN);
+#elif defined PICO_VBUS_PIN
+    gpio_set_function(PICO_VBUS_PIN, GPIO_FUNC_SIO);
+    return gpio_get(PICO_VBUS_PIN);
+#else
+#error "No VBUS Pin available!"
+#endif
+}
+
+float lipo_voltage(void) {
+#ifndef PICO_VSYS_PIN
+#error "No VSYS Pin available!"
+#endif
+
+#if CYW43_USES_VSYS_PIN
+    cyw43_thread_enter();
+    // Make sure cyw43 is awake
+    cyw43_arch_gpio_get(CYW43_WL_GPIO_VBUS_PIN);
+#endif
+
+    // setup adc
+    adc_gpio_init(PICO_VSYS_PIN);
+    adc_select_input(PICO_VSYS_PIN - PICO_FIRST_ADC_PIN);
+
+    adc_fifo_setup(true, false, 0, false, false);
+    adc_run(true);
+
+    // We seem to read low values initially - this seems to fix it
+    int ignore_count = PICO_POWER_SAMPLE_COUNT;
+    while (!adc_fifo_is_empty() || ignore_count-- > 0) {
+        (void)adc_fifo_get_blocking();
+    }
+
+    // read vsys
+    uint32_t vsys = 0;
+    for(int i = 0; i < PICO_POWER_SAMPLE_COUNT; i++) {
+        uint16_t val = adc_fifo_get_blocking();
+        vsys += val;
+    }
+
+    adc_run(false);
+    adc_fifo_drain();
+
+    vsys /= PICO_POWER_SAMPLE_COUNT;
+
+#if CYW43_USES_VSYS_PIN
+    cyw43_thread_exit();
+#endif
+
+    // Generate voltage
+    const float conversion_factor = 3.3f / (1 << 12);
+    return vsys * 3 * conversion_factor;
+}
+
+float lipo_percentage(float voltage) {
+    float percentage = 100.0f * ((voltage - empty_battery) / (full_battery - empty_battery));
+    if (percentage >= 100.0f) {
+        percentage = 100.0f;
+    } else if (percentage < 0.0f) {
+        percentage = 0.0f;
+    }
+    return percentage;
+}

src/main.c

@@ -19,6 +19,7 @@
 #include "pico/stdlib.h"
 #include "pico/cyw43_arch.h"
 #include "hardware/watchdog.h"
+#include "hardware/adc.h"
 
 #include "config.h"
 #include "util.h"
@@ -39,6 +40,9 @@ int main(void) {
         debug("reset by watchdog");
     }
 
+    // required for LiPo voltage reading
+    adc_init();
+
     if (cyw43_arch_init()) {
         debug("cyw43_arch failed");
     }

src/usb_descriptors.c

@@ -43,7 +43,7 @@
  *   [MSB]         HID | MSC | CDC          [LSB]
  */
 #define _PID_MAP(itf, n) ((CFG_TUD_##itf) << (n))
-#define USB_PID (0x4200 | _PID_MAP(CDC, 0) | _PID_MAP(MSC, 1) \
+#define USB_PID (0x2300 | _PID_MAP(CDC, 0) | _PID_MAP(MSC, 1) \
     | _PID_MAP(HID, 2) | _PID_MAP(MIDI, 3) | _PID_MAP(VENDOR, 4) )
 
 #define USB_VID   0xCafe