Fix ADC implementation so it works! Fixes incorrect return type, adds…

… +1 to top_count, fixes missing pwm_config_set_wrap() call.

platform/mbed_lib.json

@@ -159,7 +159,7 @@
         },
         "minimal-printf-enable-floating-point": {
             "help": "Enable floating point printing when using minimal printf library",
-            "value": false
+            "value": true
         },
         "minimal-printf-set-floating-point-max-decimals": {
             "help": "Maximum number of decimals to be printed when using minimal printf library",

targets/TARGET_RASPBERRYPI/TARGET_RP2040/analogin_api.c

@@ -22,9 +22,8 @@
 #include "pinmap.h"
 #include "PeripheralPins.h"
 
-static float    const ADC_VREF_VOLTAGE     = 3.3f; /* 3.3V */
 static uint16_t const ADC_RESOLUTION_BITS   = 12;
-static float    const ADC_CONVERSION_FACTOR = ADC_VREF_VOLTAGE / (1 << 16);
+static float    const ADC_CONVERSION_FACTOR = 1.0f / (1 << 16);
 
 void analogin_init(analogin_t *obj, PinName pin)
 {

targets/TARGET_RASPBERRYPI/TARGET_RP2040/pwmout_api.c

@@ -27,8 +27,17 @@
 
 #include <math.h>
 
+// Change to 1 to enable debug prints of what's being calculated.
+// Must comment out the critical section calls in PwmOut to use.
+#define RP2040_PWMOUT_DEBUG 0
+
+#if RP2040_PWMOUT_DEBUG
+#include <stdio.h>
+#include <inttypes.h>
+#endif
+
 /// Largest top count value supported by hardware.  Using this value will provide the highest duty cycle resolution,
-/// but will limit the period to a maximum of (1 / (125 MHz / 65534) =) 524 us
+/// but will limit the period to a maximum of (1 / (125 MHz / (65534 + 1)) =) 524 us
 const uint16_t MAX_TOP_COUNT = 65534;
 
 /// Value for PWM_CHn_DIV register that produces a division of 1
@@ -37,29 +46,34 @@ const uint16_t PWM_CHn_DIV_1 = 0x010;
 /// Calculate the effective PWM period (in floating point seconds) based on a divider and top_count value
 static float calc_effective_pwm_period(float divider, uint16_t top_count)
 {
-    return 1.0f / (clock_get_hz(clk_sys) / divider / top_count);
+    // Note: The hardware counts to top_count *inclusively*, so we have to add 1
+    // to get the number of clock cycles that a given top_count value will produce
+    return 1.0f / ((clock_get_hz(clk_sys) / divider) / (top_count + 1));
 }
 
 /// Calculate the best possible top_count value (rounding up) for a divider and a desired pwm period
 static uint16_t calc_top_count_for_period(float divider, float desired_pwm_period)
 {
     // Derivation:
-    // desired_pwm_period = 1.0f / ((clock_get_hz(clk_sys) / divider) / top_count)
-    // desired_pwm_period = top_count / (clock_get_hz(clk_sys) / divider)
-    // desired_pwm_period * (clock_get_hz(clk_sys) / divider) = top_count
+    // desired_pwm_period = 1.0f / ((clock_get_hz(clk_sys) / divider) / (top_count + 1))
+    // desired_pwm_period = (top_count + 1) / (clock_get_hz(clk_sys) / divider)
+    // desired_pwm_period * (clock_get_hz(clk_sys) / divider) - 1 = top_count
 
-    return ceilf(desired_pwm_period * (clock_get_hz(clk_sys) / divider));
+    long top_count_float = lroundf(desired_pwm_period * (clock_get_hz(clk_sys) / divider) - 1);
+    MBED_ASSERT(top_count_float <= MAX_TOP_COUNT);
+    return (uint16_t)top_count_float;
 }
 
 /// Calculate the best possible floating point divider value for a desired pwm period.
 /// This function assumes that top_count is set to MAX_TOP_COUNT.
-static uint16_t calc_divider_for_period(float desired_pwm_period)
+static float calc_divider_for_period(float desired_pwm_period)
 {
     // Derivation:
-    // (desired_pwm_period * clock_get_hz(clk_sys)) / divider = top_count
-    // divider = (desired_pwm_period * clock_get_hz(clk_sys)) / top_count
+    // (desired_pwm_period * clock_get_hz(clk_sys)) / divider - 1 = top_count
+    // (desired_pwm_period * clock_get_hz(clk_sys)) / divider = top_count + 1
+    // divider = (desired_pwm_period * clock_get_hz(clk_sys)) / (top_count + 1)
 
-    return (desired_pwm_period * clock_get_hz(clk_sys)) / MAX_TOP_COUNT;
+    return (desired_pwm_period * clock_get_hz(clk_sys)) / (MAX_TOP_COUNT + 1);
 }
 
 /// Convert PWM divider from floating point to a fixed point number (rounding up).
@@ -126,19 +140,23 @@ void pwmout_write(pwmout_t *obj, float percent)
     obj->percent = percent;
 
     // Per datasheet section 4.5.2.2, a period value of top_count + 1 produces 100% duty cycle
-    int32_t reset_count = lroundf((obj->top_count + 1) * percent);
+    int32_t new_reset_counts = lroundf((obj->top_count + 1) * percent);
 
     // Clamp to valid values
-    if(reset_count > obj->top_count + 1)
+    if(new_reset_counts > obj->top_count + 1)
     {
-        reset_count = obj->top_count + 1;
+        new_reset_counts = obj->top_count + 1;
     }
-    else if(reset_count < 0)
+    else if(new_reset_counts < 0)
     {
-        reset_count = 0;
+        new_reset_counts = 0;
     }
 
-    pwm_set_chan_level(obj->slice, obj->channel, reset_count);
+#if RP2040_PWMOUT_DEBUG
+    printf("new_reset_counts: %" PRIu32 "\n", new_reset_counts);
+#endif
+
+    pwm_set_chan_level(obj->slice, obj->channel, new_reset_counts);
     pwm_set_enabled(obj->slice, true);
 }
 
@@ -197,11 +215,26 @@ void pwmout_period(pwmout_t *obj, float period)
 
         // Step 4: For best accuracy, recalculate the top_count value using the divider.
         obj->top_count = calc_top_count_for_period(obj->clock_divider, period);
+
+#if RP2040_PWMOUT_DEBUG
+        printf("period = %f, desired_divider = %f\n",
+               period,
+               desired_divider);
+#endif
     }
 
     // Save period for later
     obj->period = period;
 
+#if RP2040_PWMOUT_DEBUG
+    printf("obj->clock_divider = %f, obj->cfg.div = %" PRIu32 ", obj->top_count = %" PRIu16 "\n",
+           obj->clock_divider,
+           obj->cfg.div,
+           obj->top_count);
+#endif
+
+    // Set the new divider and top_count values.
+    pwm_config_set_wrap(&(obj->cfg), obj->top_count);
     pwm_init(obj->slice, &(obj->cfg), false);
 }
 

targets/targets.json5

@@ -4876,7 +4876,12 @@
         "device_name": "STM32U575ZITx",
         "detect_code": [
             "886"
-        ]
+        ],
+        "overrides": {
+            // As shipped, this nucleo board connects VREFP to VDD_MCU, and connects VDD_MCU to 3.3V.
+            // Jumper JP4 can be used to switch VDD_MCU to 1.8V in which case you should override this setting to 1.8.
+            "default-adc-vref": 3.3
+        }
     },
 	"MCU_STM32U585xI": {
         "inherits": [
@@ -9758,21 +9763,32 @@
             "RTC"
         ]
     },
-    "RASPBERRY_PI_PICO_SWD": {
+    "RASPBERRY_PI_PICO": {
         "inherits": ["RP2040"],
         "macros_add": [
             "PICO_RP2040_USB_DEVICE_ENUMERATION_FIX=1",
             "MBED_MPU_CUSTOM",
             "PICO_TIME_DEFAULT_ALARM_POOL_DISABLED",
             "PICO_ON_DEVICE=1",
             "PICO_UART_ENABLE_CRLF_SUPPORT=0"
-        ]
-    },
-    "RASPBERRY_PI_PICO": {
-        "inherits": ["RASPBERRY_PI_PICO_SWD"],
+        ],
         "overrides": {
             "console-usb": true,
-            "console-uart": false
+            "console-uart": false,
+
+            // ADC_VDD sets the ADC reference voltage on this chip.
+            // Most RP2040 boards set this pin to 3.3V.
+            // Note that if the I/O voltage is set to less than the ADC reference voltage,
+            // voltages higher than the I/O voltage are illegal for the analog pins
+            // (so the ADC can never read 100%).
+            "default-adc-vref": 3.3
+        }
+    },
+    "RASPBERRY_PI_PICO_SWD": {
+        "inherits": ["RASPBERRY_PI_PICO"],
+        "overrides": {
+            "console-usb": false,
+            "console-uart": true
         }
     }
 }