Adding script to control cheetah spi adapter and test vSPI

scripts/master/spitest.py

+from cheetah_py import *
+from time import *
+
+def print_usage():
+  print \
+"""
+usage: spitest.py PORT
+"""
+
+if (len(sys.argv) < 2):
+  print_usage()
+  sys.exit(1)
+
+port      = int(sys.argv[1])
+mode      = 2
+bitrate   = 40000  # kbps
+byteCount = 11   # bytes
+
+# Open the device
+handle = ch_open(port)
+if (handle <= 0):
+  print "Unable to open Cheetah device on port %d" % port
+  print "Error code = %d (%s)" % (handle, ch_status_string(handle))
+  sys.exit(1)
+
+print "Opened Cheetah device on port %d" % port
+
+ch_host_ifce_speed_string = ""
+if (ch_host_ifce_speed(handle)):
+  ch_host_ifce_speed_string = "high speed"
+else:
+  ch_host_ifce_speed_string = "full speed"
+print "Host interface is %s" % ch_host_ifce_speed_string
+
+# Ensure that SPI subsystem is configured
+ch_spi_configure(handle, (mode >> 1), mode & 1, CH_SPI_BITORDER_MSB, 0x0)
+print "SPI configuration set to mode %d, MSB shift, SS[2:0] active low" % mode
+sys.stdout.flush()
+
+# Set the bitrate
+bitrate = ch_spi_bitrate(handle, bitrate)
+print "Bitrate set to %d kHz" % bitrate
+sys.stdout.flush()
+
+# Create 4KB of fake data so we can exchange it for real data
+data_in = array('B', [0 for i in range(byteCount)])
+ch_spi_queue_clear(handle)
+ch_spi_queue_oe(handle, 1)
+#ch_spi_queue_byte(handle, 1, 0x00) # Send an empty byte, pre SS low
+ch_spi_queue_ss(handle, 0x1)
+#ch_spi_queue_byte(handle, 1, 0x02)  # Send to MOSI buffer
+#ch_spi_queue_byte(handle, 3, 0x00)  # Sending 4 bytes
+#ch_spi_queue_byte(handle, 1, 0x04)
+#ch_spi_queue_byte(handle, 1, 0xFF)  # Sending byte: 1111_1111
+#ch_spi_queue_byte(handle, 1, 0xF0)  # Sending byte: 1111_0000
+#ch_spi_queue_byte(handle, 1, 0x33)  # Sending byte: 0011_0011
+ch_spi_queue_byte(handle, 1, 42)  # Sending byte: 0101_0101
+
+#ch_spi_queue_byte(handle, 1, 0x55) # Test byte
+#ch_spi_queue_byte(handle, 1, 0x66)
+
+
+ch_spi_queue_ss(handle, 0)
+
+#ch_spi_queue_byte(handle, 1, 0x00) # Send an empty byte, SS high
+
+
+(actualByteCount, data_in) = ch_spi_batch_shift(handle, byteCount)
+
+#if (actualByteCount < 0):
+#  print "error: %s" % ch_status_string(count)
+#elif (actualByteCount != byteCount):
+#  print "error: read %d bytes (expected %d)" % (actualByteCount, byteCount)
+#else:
+for i in range(actualByteCount):
+  sys.stdout.write("%d " % data_in[i])
+sys.stdout.write("\n")
+
+# Close and exit
+ch_close(handle)
+sys.exit(0)
+