periph/adc_continous: add test for ADC continous API

tests/periph/adc_continuous/Makefile

@@ -0,0 +1,9 @@
+BOARD ?= same54-xpro
+include ../Makefile.periph_common
+
+FEATURES_REQUIRED += periph_adc
+FEATURES_REQUIRED += periph_adc_continuous
+USEMODULE += ztimer
+USEMODULE += ztimer_msec
+
+include $(RIOTBASE)/Makefile.include

tests/periph/adc_continuous/Makefile.ci

@@ -0,0 +1,3 @@
+BOARD_INSUFFICIENT_MEMORY := \
+    atmega8 \
+    #

tests/periph/adc_continuous/README.md

@@ -0,0 +1,13 @@
+Expected result
+===============
+When running this test, you should see the samples of all configured ADC lines
+continuously streamed to std-out.
+
+Background
+==========
+This test application will initialize each configured ADC lines to sample with
+10-bit accuracy. Once configured the application will continuously convert each
+available channel and print the conversion results to std-out.
+
+For verification of the output connect the ADC pins to known voltage levels
+and compare the output.

tests/periph/adc_continuous/main.c

@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2014-2015 Freie Universität Berlin
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @ingroup     tests
+ * @{
+ *
+ * @file
+ * @brief       Test application for peripheral ADC drivers
+ *
+ * @author      Hauke Petersen <hauke.petersen@fu-berlin.de>
+ *
+ * @}
+ */
+
+#include <stdio.h>
+
+#include "ztimer.h"
+#include "periph/adc.h"
+
+#define RES             ADC_RES_10BIT
+#define DELAY_MS        100U
+
+int main(void)
+{
+    int sample = 0;
+
+    puts("\nRIOT ADC peripheral driver test\n");
+    puts("This test will sample all available ADC lines once every 100ms with\n"
+         "a 10-bit resolution and print the sampled results to STDIO\n\n");
+
+    /* initialize all available ADC lines */
+    for (unsigned i = 0; i < ADC_NUMOF; i++) {
+        if (adc_init(ADC_LINE(i)) < 0) {
+            printf("Initialization of ADC_LINE(%u) failed\n", i);
+            return 1;
+        } else {
+            printf("Successfully initialized ADC_LINE(%u)\n", i);
+        }
+    }
+
+    adc_continuous_begin(RES);
+    while (1) {
+        for (unsigned i = 0; i < ADC_NUMOF; i++) {
+            sample = adc_continuous_sample(ADC_LINE(i));
+            printf("ADC_LINE(%u): %i\n", i, sample);
+        }
+        ztimer_sleep(ZTIMER_MSEC, DELAY_MS);
+    }
+
+    adc_continuous_stop();
+    return 0;
+}