Initial Release

adc/CMakeLists.txt

@@ -0,0 +1,5 @@
+if (NOT PICO_NO_HARDWARE)
+    add_subdirectory(adc_console)
+    add_subdirectory(hello_adc)
+    add_subdirectory(joystick_display)
+endif ()

adc/adc_console/CMakeLists.txt

@@ -0,0 +1,12 @@
+add_executable(adc_console
+        adc_console.c
+        )
+
+target_link_libraries(adc_console pico_stdlib hardware_adc)
+
+# create map/bin/hex file etc.
+pico_add_extra_outputs(adc_console)
+
+# add url via pico_set_program_url
+example_auto_set_url(adc_console)
+

adc/adc_console/adc_console.c

@@ -0,0 +1,100 @@
+#include <stdio.h>
+#include "pico/stdlib.h"
+#include "hardware/gpio.h"
+#include "hardware/adc.h"
+
+#define N_SAMPLES 1000
+uint16_t sample_buf[N_SAMPLES];
+
+void printhelp() {
+    puts("\nCommands:");
+    puts("c0, ...\t: Select ADC channel n");
+    puts("s\t: Sample once");
+    puts("S\t: Sample many");
+    puts("w\t: Wiggle pins");
+}
+
+void __not_in_flash_func(adc_capture)(uint16_t *buf, size_t count) {
+    adc_fifo_setup(true, false, 0, false, false);
+    adc_run(true);
+    for (int i = 0; i < count; i = i + 1)
+        buf[i] = adc_fifo_get_blocking();
+    adc_run(false);
+    adc_fifo_drain();
+}
+
+int main(void) {
+    stdio_init_all();
+    adc_init();
+    adc_set_temp_sensor_enabled(true);
+
+    // Set all pins to input (as far as SIO is concerned)
+    gpio_set_dir_all_bits(0);
+    for (int i = 2; i < 30; ++i) {
+        gpio_set_function(i, GPIO_FUNC_SIO);
+        if (i >= 26) {
+            gpio_disable_pulls(i);
+            gpio_set_input_enabled(i, false);
+        }
+    }
+
+    printf("\n===========================\n");
+    printf("RP2040 ADC and Test Console\n");
+    printf("===========================\n");
+    printhelp();
+
+    while (1) {
+        char c = getchar();
+        printf("%c", c);
+        switch (c) {
+            case 'c':
+                c = getchar();
+                printf("%c\n", c);
+                if (c < '0' || c > '7') {
+                    printf("Unknown input channel\n");
+                    printhelp();
+                } else {
+                    adc_select_input(c - '0');
+                    printf("Switched to channel %c\n", c);
+                }
+                break;
+            case 's': {
+                uint32_t result = adc_read();
+                const float conversion_factor = 3.3f / (1 << 12);
+                printf("\n0x%03x -> %f V\n", result, result * conversion_factor);
+                break;
+            }
+            case 'S': {
+                printf("\nStarting capture\n");
+                adc_capture(sample_buf, N_SAMPLES);
+                printf("Done\n");
+                for (int i = 0; i < N_SAMPLES; i = i + 1)
+                    printf("%03x\n", sample_buf[i]);
+                break;
+            }
+            case 'w':
+                printf("\nPress any key to stop wiggling\n");
+                int i = 1;
+                gpio_set_dir_all_bits(-1);
+                while (getchar_timeout_us(0) == PICO_ERROR_TIMEOUT) {
+                    // Pattern: Flash all pins for a cycle,
+                    // Then scan along pins for one cycle each
+                    i = i ? i << 1 : 1;
+                    gpio_put_all(i ? i : ~0);
+                }
+                gpio_set_dir_all_bits(0);
+                printf("Wiggling halted.\n");
+                break;
+            case '\n':
+            case '\r':
+                break;
+            case 'h':
+                printhelp();
+                break;
+            default:
+                printf("\nUnrecognised command: %c\n", c);
+                printhelp();
+                break;
+        }
+    }
+}

adc/hello_adc/CMakeLists.txt

@@ -0,0 +1,11 @@
+add_executable(hello_adc
+        hello_adc.c
+        )
+
+target_link_libraries(hello_adc pico_stdlib hardware_adc)
+
+# create map/bin/hex file etc.
+pico_add_extra_outputs(hello_adc)
+
+# add url via pico_set_program_url
+example_auto_set_url(hello_adc)

adc/hello_adc/hello_adc.c

@@ -0,0 +1,30 @@
+/**
+ * Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <stdio.h>
+#include "pico/stdlib.h"
+#include "hardware/gpio.h"
+#include "hardware/adc.h"
+
+int main() {
+    stdio_init_all();
+    printf("ADC Example, measuring GPIO26\n");
+
+    adc_init();
+
+    // Make sure GPIO is high-impedance, no pullups etc
+    adc_gpio_init(26);
+    // Select ADC input 0 (GPIO26)
+    adc_select_input(0);
+
+    while (1) {
+        // 12-bit conversion, assume max value == ADC_VREF == 3.3 V
+        const float conversion_factor = 3.3f / (1 << 12);
+        uint16_t result = adc_read();
+        printf("Raw value: 0x%03x, voltage: %f V\n", result, result * conversion_factor);
+        sleep_ms(500);
+    }
+}

adc/joystick_display/CMakeLists.txt

@@ -0,0 +1,11 @@
+add_executable(joystick_display
+        joystick_display.c
+        )
+
+target_link_libraries(joystick_display pico_stdlib hardware_adc)
+
+# create map/bin/hex file etc.
+pico_add_extra_outputs(joystick_display)
+
+# add url via pico_set_program_url
+example_auto_set_url(joystick_display)

adc/joystick_display/joystick_display.c

@@ -0,0 +1,40 @@
+/**
+ * Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <stdio.h>
+#include "pico/stdlib.h"
+#include "hardware/adc.h"
+
+int main() {
+    stdio_init_all();
+    adc_init();
+    // Make sure GPIO is high-impedance, no pullups etc
+    adc_gpio_init(26);
+    adc_gpio_init(27);
+
+    while (1) {
+        adc_select_input(0);
+        uint adc_x_raw = adc_read();
+        adc_select_input(1);
+        uint adc_y_raw = adc_read();
+
+        // Display the joystick position something like this:
+        // X: [            o             ]  Y: [              o         ]
+        const uint bar_width = 40;
+        const uint adc_max = (1 << 12) - 1;
+        uint bar_x_pos = adc_x_raw * bar_width / adc_max;
+        uint bar_y_pos = adc_y_raw * bar_width / adc_max;
+        printf("\rX: [");
+        for (int i = 0; i < bar_width; ++i)
+            putchar( i == bar_x_pos ? 'o' : ' ');
+        printf("]  Y: [");
+        for (int i = 0; i < bar_width; ++i)
+            putchar( i == bar_y_pos ? 'o' : ' ');
+        printf("]");
+        sleep_ms(50);
+
+    }
+}