Logitech C270 testing notes

I found RPi TP2 dropped to 4.85V from 5.01V when the webcam C270 is connected.  It is likely that when the webcam tries to capture something, the TP2 would drop further to below 4.75V, and perhaps that is why the RPi system hangs and could not exit even by pressing Ctrl-C.

So I think I should power up the hub.  I found that when the USB hub is power, the RPi TP2 no longer drops so much, this time only to 5.01V when power supply is 5.3V.

But I still got the following error message.

  SystemError: ioctl(VIDIOC_S_FMT) failure: no supported formats

Next step is to check out the cause of this error.


*** Start Program - FongToy v1.7 tlfong01 2013jun10 ***

*** Sample run begin - Test web cam 2013jun11 ***

List of available cameras =  ['/dev/video0']
Traceback (most recent call last):
  File "fongtoy.py", line 77, in <module>
    ftwebcam.TestWebcam()
  File "/home/pi/fongtoy/ftwebcam.py", line 44, in TestWebcam
    webCam.start()
SystemError: ioctl(VIDIOC_S_FMT) failure: no supported formats

pi@raspberrypi ~/fongtoy $ lsusb
Bus 001 Device 002: ID 0424:9512 Standard Microsystems Corp.
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp.
Bus 001 Device 004: ID 0586:341f ZyXEL Communications Corp. NWD2205 802.11n Wireless N Adapter [Realtek RTL8192CU]
Bus 001 Device 005: ID 1a40:0101 Terminus Technology Inc. 4-Port HUB
Bus 001 Device 006: ID 046d:0825 Logitech, Inc. Webcam C270
pi@raspberrypi ~/fongtoy $ date
Tue Jun 11 02:56:47 UTC 2013
pi@raspberrypi ~/fongtoy $


# ftwebcam v0.2 tlfong01 2013jun11

# *****************************************************************************
# Module - ftwebcam.py
# Description - Test Logitech webcam C920 and C270
# Reference
#   Pygame.camera Reference - http://www.pygame.org/docs/ref/camera.html
#   Pygame.camera Turorial -  http://www.pygame.org/docs/tut/camera/CameraIntro.html
# Notes
#   Image zise 2MP 16:9 = 1920 * 1080 = 2,073,600
# *****************************************************************************

# *****************************************************************************
# Imports
# *****************************************************************************

import time

import pygame
import pygame.camera
from pygame.locals import *

import ftprint

# *****************************************************************************
# Function - TestWebcam()
# Description -
#   Test Webcam
# *****************************************************************************

def TestWebcam():

    ftprint.PrintDoubleSpaceLine("*** Sample run begin - Test web cam 2013jun11 ***")  

    pygame.init()
    pygame.camera.init()

    webCamList = pygame.camera.list_cameras()
    if webCamList:
        print "List of available cameras = ", webCamList
        webCam = pygame.camera.Camera(webCamList[0],(640,480))

    webCam = pygame.camera.Camera("/dev/video0",(640,480))
    webCam.start()
    webCamImage = webCam.get_image()

    ftprint.PrintDoubleSpaceLine("*** Sample run end ***")

# .END


# *** Main program ***

# *** Start program message ***
ftprint.StartProgram(ProgramTitle)

# *** Main tests ***

# *** SPI loop back ***
# ftspi.TestSpiLoopBackV01(spiChannelNumber = 0, spiChipEnableNumber = 1, testDataByte = 0x55, testTime = 0.001, testCount = 60000)

# *** ADC ***
# ftadc.TestMcp3208v03()
# ftadc.TestMcp3201v04()

# *** EEPROM ***
# fteeprom.TestEeporm25Lc256v01(spiChannelNumber = 0, spiChipEnableNumber = 1, startAddress = 0x4100, testDataByte = 0x55)

# *** Mcp23s17 ***
# ftiox.TestMcp23s17BlinkLed(spiChannelNumber = 0, spiChipEnableNumber = 0, spiChipSubAddress = 0)

# *** Demux ***
# ftdemux.TestDemuxV01(spiChannelNumber = 0, spiChipEnableNumber = 0, spiIoxSubAddress = 0, spiSlaveDeviceNumber = 5)

# *** Guzunty Pi Step Motor ***
# ... test functions already moved to ftguzunti.py tlfong01 2013jun10 ...

# *** Webcam ***

ftwebcam.TestWebcam()

# *** Stop program message ***

ftprint.StopProgram()

# .END