examples: Add standard SPI AD3552R triggered example

Add example for using AD3552R connected through standard SPI interface
pushing data in with a triggered buffer.

Signed-off-by: Marcelo Schmitt <[email protected]>

examples/ad3552r_triggered_example.py

@@ -0,0 +1,66 @@
+import sys
+import time
+from test.eeprom import read_fru_eeprom
+
+import adi
+import matplotlib.pyplot as plt
+import numpy as np
+import os
+
+# Optionally pass URI as command line argument,
+# else use default ip:analog.local
+
+my_uri = sys.argv[1] if len(sys.argv) >= 2 else "ip:analog.local"
+print("uri: " + str(my_uri))
+
+# device connections
+
+ad3552r = adi.ad3552r(uri=my_uri, device_name="ad3552r")
+
+# device configurations
+
+# Upstream ad3552r driver supports triggered buffer transfer so we will use that.
+# We need to enable the buffer, set buffer lenght, and enable scan elements.
+# Fill the buffer with output to DAC.
+# Create sysfs trigger and attatch it to the buffer/device.
+# Fire the trigger so the driver pushes buffer data to DAC device.
+
+# Create sysfs trigger
+trigger_index="0"
+trigger_name="trigger0"
+os.system("echo "+trigger_index+"> /sys/bus/iio/devices/iio_sysfs_trigger/add_trigger")
+
+# Set default trigger
+dac_trigger = self._ctx.find_device(trigger_name)
+ad3552r._txdac._set_trigger(dac_trigger)
+
+# Generate TX signal
+fs = int(ad3552r.sample_rate)
+# Signal frequency
+fc = 80000
+# Number of samples
+N = int(fs / fc)
+# Period
+ts = 1 / float(fs)
+# Time array
+t = np.arange(0, N * ts, ts)
+# Sine generation
+samples = np.sin(2 * np.pi * t * fc)
+# Amplitude (full_scale / 2)
+samples *= (2 ** 15) - 1
+# Offset (full_scale / 2)
+samples += 2 ** 15
+# conversion to unsigned int and offset binary
+samples = np.uint16(samples)
+samples = np.bitwise_xor(32768, samples)
+
+ad3552r.tx_enabled_channels = [0, 1]
+ad3552r.tx_cyclic_buffer = True
+ad3552r.tx([samples, samples])
+
+plt.suptitle("AD355R Samples data")
+plt.plot(t, np.bitwise_xor(32768, samples))
+plt.xlabel("Samples")
+plt.show()
+
+ad3552r.tx_destroy_buffer()