tests/driver_dsp0401: add simple test application

tests/driver_dsp0401/Makefile

+APPLICATION = driver_dsp0401
+include ../Makefile.tests_common
+
+USEMODULE += dsp0401
+
+LOOPS ?= 3
+CFLAGS += -DLOOPS=${LOOPS}
+
+include $(RIOTBASE)/Makefile.include

tests/driver_dsp0401/README.md

+## About
+
+This is a test application for the [DSP0401](https://www.embeddedadventures.com/datasheets/DSP-0401B_hw_v4.pdf),
+a 4 digits with 16 segments alpha-numeric display.
+
+## Connecting the device
+
+The display can be controlled from the JP1 connection jumper as follows:
+* Connect `SIN` to the board `DSP0401_PARAM_SDI_PIN` (see your board_params.h file)
+* Connect `CLK` to the board `DSP0401_PARAM_CLK_PIN`
+* Connect `LAT` to the board `DSP0401_PARAM_LAT_PIN`
+* Connect `PWM` to the board `DSP0401_PARAM_PWM_DEV` pwm device. See the board periph_conf.h
+to find a valid pin and configuration.
+* Connect `VCC` to one of the board VCC pin (3.3V or 5V depending on your board.
+  Example: use 3.3V with ST Nucleo)
+* Connect `GND` to one of the board GND.
+
+Since there are potentially a lot of LEDs to poweron, it's preferable to use an
+external power supply to power the DSP0401 module. This is what JP2 is meant for.
+See the [datasheet](https://www.embeddedadventures.com/datasheets/DSP-0401B_hw_v4.pdf)
+section `Power` for more information on power configuration.
+
+## Chaining devices
+
+Since DSP0401 contains a shift register, it's possible to chain devices by connecting
+the JP4 and JP5 connection jumpers of the device N to respectively JP2 and JP1 of the
+device N+1.
+Attention: ensure your power supply is able to provide enough current for the number of devices
+you plan to use.

tests/driver_dsp0401/main.c

+/*
+ * Copyright (C) 2017 Inria
+ *
+ * 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 the DSP0401 4 digit display.
+ *
+ * @author      Alexandre Abadie <alexandre.abadie@inria.fr>
+ *
+ * @}
+ */
+
+#include <stdio.h>
+#include <inttypes.h>
+
+#include "dsp0401_params.h"
+#include "dsp0401.h"
+#include "xtimer.h"
+
+#define TEST_DELAY      (2U)               /* 2 seconds delay between each test */
+#define WORD_DELAY      (750U)             /* 750 milliseconds delay between each word */
+#define SCROLL_DELAY    (200U)             /* 200 milliseconds delay between character shift */
+#ifndef LOOPS
+#define LOOPS           (3U)               /* Number of display loops before exit */
+#endif
+
+int main(void)
+{
+    dsp0401_t dev;
+
+    puts("Starting DSP0401 test application\n");
+
+    puts("Initializing DSP4010 device.");
+    if (dsp0401_init(&dev, &dsp0401_params[0]) != DSP0401_OK) {
+        puts("[Error] Cannot initialize DSP0401 display.");
+        return 1;
+    }
+
+    puts("Initialization successful\n");
+    uint8_t loop = 0;
+    while (loop < LOOPS) {
+        puts("[INFO] Displaying 'THIS IS RIOT'");
+        dsp0401_display_text(&dev, (char*)"THIS");
+        xtimer_usleep(WORD_DELAY * US_PER_MS);
+        dsp0401_display_text(&dev, (char*)" IS ");
+        xtimer_usleep(WORD_DELAY * US_PER_MS);
+        dsp0401_display_text(&dev, (char*)"RIOT");
+        xtimer_sleep(TEST_DELAY);
+
+        puts("[INFO] Clearing text!");
+        dsp0401_clear_text(&dev);
+        xtimer_sleep(TEST_DELAY);
+
+        puts("[INFO] Scrolling 'THIS IS RIOT'");
+        dsp0401_scroll_text(&dev, (char*)("THIS IS RIOT"), SCROLL_DELAY);
+        xtimer_sleep(TEST_DELAY);
+        puts("[INFO] Done\n");
+        ++loop;
+    }
+
+    puts("SUCCESS");
+
+    return 0;
+}