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helloworld.py
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Fri, Mar 21, 18:04

helloworld.py
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#!/usr/bin/python
# -*- coding: utf-8 -*-
import os, sys
# add ../../Sources to the PYTHONPATH
sys.path.append(os.path.join("..", "..", "Sources"))
from yocto_api import *
from yocto_spiport import *
def usage():
scriptname = os.path.basename(sys.argv[0])
print("Usage:")
print(scriptname + " <serial_number> <value>")
print(scriptname + " <logical_name> <value>")
print(scriptname + " any <value> (use any discovered device)")
sys.exit()
def die(msg):
sys.exit(msg + ' (check USB cable)')
if len(sys.argv) < 3:
usage()
target = sys.argv[1].upper()
value = int(sys.argv[2])
# Setup the API to use local USB devices. You can
# use an IP address instead of 'usb' if the device
# is connected to a network.
errmsg = YRefParam()
if YAPI.RegisterHub("usb", errmsg) != YAPI.SUCCESS:
sys.exit("init error" + errmsg.value)
if target == 'ANY':
spiPort = YSpiPort.FirstSpiPort()
if spiPort is None:
sys.exit('No module connected (check cable)')
else:
spiPort = YSpiPort.FindSpiPort(sys.argv[1] + ".spiPort")
if not spiPort.isOnline():
sys.exit('Module not connected')
# sample code driving MAX7219 7-segment display driver
# such as SPI7SEGDISP8.56 from www.embedded-lab.com
spiPort.set_spiMode("250000,3,msb")
spiPort.set_ssPolarity(YSpiPort.SSPOLARITY_ACTIVE_LOW)
spiPort.set_protocol("Frame:5ms")
spiPort.reset()
# do not forget to onfigure the powerOutput of the Yocto - SPI
# (for SPI7SEGDISP8.56 powerOutput need to be set at 5v)
print("****************************")
print("* make sure voltage levels *")
print("* are properly configured *")
print("****************************")
# initialize MAX7219
spiPort.writeHex('0c01') # Exit from shutdown state
spiPort.writeHex('09ff') # Enable BCD for all digits
spiPort.writeHex('0b07') # Enable digits 0-7 (=8 in total)
spiPort.writeHex('0a0a') # Set medium brightness
for i in range(1, 9):
digit = value % 10
spiPort.writeArray([i, digit])
value = int(value / 10)
YAPI.FreeAPI()

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