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by bgreat
Wed Apr 10, 2013 3:06 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: SPI ADC was working fine last week and now it's not
Replies: 27
Views: 6029

Re: SPI ADC was working fine last week and now it's not

The rmmod/modprobe commands basically remove the SPI driver from memory and then restart it. If the driver is corrupted or an incompatible version you should receive a message indicating a problem when the modprobe command is executed. Barring an issue with your wiring or ADC, it is possible you hav...
by bgreat
Tue Apr 09, 2013 6:21 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: SPI ADC was working fine last week and now it's not
Replies: 27
Views: 6029

Re: SPI ADC was working fine last week and now it's not

It almost seems that the SPI is not enabled for the GPIO lines. I recall an earlier thread that discussed an issue with using the SPI for GPIO and then attempting to use it for SPI required a reboot. Can you confirm that no other application has used the same GPIO pins for IO before you run your pro...
by bgreat
Mon Apr 08, 2013 11:42 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: SPI ADC was working fine last week and now it's not
Replies: 27
Views: 6029

Re: SPI ADC was working fine last week and now it's not

I reviewed the code and connections again and I see nothing incorrect in the implementation. I can only suggest a few rudimentary tests to confirm everything is as you expect. 1. Confirm that you are using xfer and not xfer2. 2. Using a multimeter, confirm the ADC input from the potentiometer varies...
by bgreat
Mon Apr 08, 2013 6:45 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: SPI ADC was working fine last week and now it's not
Replies: 27
Views: 6029

Re: SPI ADC was working fine last week and now it's not

Sorry for the delay, but I have been rather busy. Nothing obvious in the wiring. I will take a closer look at this tonight on my Raspberry Pi and post back.

Enjoy!
Bill
by bgreat
Thu Apr 04, 2013 1:20 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: SPI ADC was working fine last week and now it's not
Replies: 27
Views: 6029

Re: SPI ADC was working fine last week and now it's not

Please post a drawing of how you have MCP3004 connected and your code. Unless there is a hardware failure, the issue is either wiring or software. With the additional information, it will be possible to help you determine the cause.

Enjoy!
Bill
by bgreat
Thu Apr 04, 2013 1:17 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: MCP3008 SPI Inaccurate readings..
Replies: 13
Views: 16022

Re: MCP3008 SPI Inaccurate readings..

Question: how are you measuring the throughput and is this without any other IO? Sometimes the limiting factor for peripheral IO is how the data is being recorded and not so much how it is being acquired. As a first test, I would do a simple read loop of the MCP3008 with no data storage and no user ...
by bgreat
Thu Apr 04, 2013 1:10 pm
Forum: Python
Topic: spidev xfer2 v xfer
Replies: 5
Views: 16400

Re: spidev xfer2 v xfer

I will look at this again, but I do remember my initial testing showed the CSx was not released between transactions when using xfer2 unless another SPI device was accessed, the SPI connection was closed, or an xfer transaction was initiated. I will not be able to look at this in depth until this we...
by bgreat
Sun Mar 31, 2013 4:09 pm
Forum: Other projects
Topic: Glowing Red Alert Button, The Octoalert
Replies: 5
Views: 3057

Re: Glowing Red Alert Button, The Octoalert

Great Dad! In no time he will be programming his own missions!

Enjoy!
Bill
by bgreat
Sun Mar 31, 2013 3:59 pm
Forum: Troubleshooting
Topic: I2C strange interference by mains
Replies: 18
Views: 3473

Re: I2C strange interference by mains

I do not know how the I2C display is wired, but I have seen similar issues when separate power supplies are used for the controller and display when the grounds are not connected common. If the display is not connected to the Raspberry Pi power supply, the display power supply ground must be connect...
by bgreat
Mon Mar 04, 2013 4:35 pm
Forum: Python
Topic: Nokia Pi LCD
Replies: 253
Views: 107418

Re: Nokia Pi LCD

Morning all. Re the comment above, I always have to remove white space when i'm posting from this board - normally end up with two spaces at least to take away. Easy enough to remove in Idle, but i'm not sure why it happens :o Steve, Are you using the "CODE: SELECT ALL" at the top of the listing in...
by bgreat
Sun Mar 03, 2013 12:51 am
Forum: Python
Topic: Nokia Pi LCD
Replies: 253
Views: 107418

Re: Nokia Pi LCD

I'm not certain, but I would consider that there is an extra non-printing character on the line with "SCE" that is causing the syntax error. Looking at your error message, it shows a pointer immediately after "SCE" before the "=". Try deleting and retyping the line: SCE = 2 # gpio pin 13 = wiringpi ...
by bgreat
Tue Feb 26, 2013 9:38 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: SPI slave devices
Replies: 6
Views: 4213

Re: SPI slave devices

The Raspberry Pi does not have hardware support to be used as a SPI slave device.

I have been experimenting with SPI LCD displays, ADCs, DACs, and port expanders. I have also done some work with high speed communication with Stellaris processors over SPI.

Enjoy!
Bill
by bgreat
Mon Feb 25, 2013 1:05 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: MCP3004 not working/noise on line
Replies: 11
Views: 5727

Re: MCP3004 not working/noise on line

A faulty pot is a possibility. Usually though ADC stability problems can be traced to noise on the power. An open connection input will be unstable. If you want a stable test value, just use two equal value resistors in series from Vcc to ground, with the center connected to the ADC input. You shoul...
by bgreat
Sun Feb 24, 2013 3:30 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: MCP3004 not working/noise on line
Replies: 11
Views: 5727

Re: MCP3004 not working/noise on line

Giving a quick look at the data sheet and your code, I see two issues. 1. You should use xfer() instead of xfer2(). xfer2() does not release the CSx line between transfers, and it is needed by the MCP3004. 2. For single ended conversion, change: r = spi.xfer2([1, (4+channel)<<4, 0]) to r = spi.xfer(...
by bgreat
Sat Feb 23, 2013 9:51 am
Forum: Python
Topic: only for the greats in socket programming
Replies: 6
Views: 1941

Re: only for the greats in socket programming

Please post your source inside using the "Code" button to preserve formatting. This makes it possible for others to review your code with the indenting as you entered. If you are connecting as a client to a telnet daemon on the "HMI" system, it is possible you are seeing the effect of the embedded t...
by bgreat
Tue Feb 19, 2013 1:32 am
Forum: Python
Topic: 20x4 i2c lcd lines out of order.
Replies: 23
Views: 23751

Re: 20x4 i2c lcd lines out of order.

The display and code are working correctly. The standard character addressing for a 20 character by 4 line display with an HD44780 controller is: LCD-20x4-memory(b).gif If you sequentially write 80 characters to the display, they will display on line 1, followed by line 3, followed by line 2, follow...
by bgreat
Mon Feb 18, 2013 9:53 pm
Forum: Deutsch
Topic: C/C++ Compiler
Replies: 3
Views: 2609

Re: C/C++ Compiler

Code: Select all

[email protected] ~ $ which gcc
/usr/bin/gcc
[email protected] ~ $ which g++
/usr/bin/g++
Oder:

Code: Select all

[email protected] ~ $ which cc
/usr/bin/cc
[email protected] ~ $ which c++
/usr/bin/c++
Viel Spaß!
Bill
by bgreat
Sun Feb 17, 2013 5:39 pm
Forum: C/C++
Topic: 74HC164N Daisy Chain Problem
Replies: 5
Views: 1547

Re: 74HC164N Daisy Chain Problem

Connect the CLK and /CLR pins of each chip together with CLK going to your GPIO driving the clock and /RST going to your GPIO for resetting the shift registers. Connect QH output(last) of the first shift register to DSA and DSB of the second shift register. Connect DSA and DSB of the first shift reg...
by bgreat
Sun Feb 17, 2013 12:24 am
Forum: Python
Topic: "GPIO.output(farray, True)" doesn't work
Replies: 2
Views: 954

Re: "GPIO.output(farray, True)" doesn't work

As the error message states, function GPIO.output() requires an integer first argument, not an array.

If you want to set an output for all pins in an array, try:

Code: Select all

for pin in array:
  GPIO.output(pin, True)
Enjoy!
Bill
by bgreat
Sat Feb 16, 2013 2:25 pm
Forum: C/C++
Topic: Qt with Wiring PI
Replies: 26
Views: 31736

Re: Qt with Wiring PI

Are you cross compiling with Qt? With multiple copies/versions of WiringPi libraries on the system, I would recommend starting from a fresh OS and Qt install with the corrected build files.

Enjoy!
Bill
by bgreat
Sat Feb 16, 2013 2:23 am
Forum: C/C++
Topic: Qt with Wiring PI
Replies: 26
Views: 31736

Re: Qt with Wiring PI

You are confusing the library and include sections in the .pro file.

In your .pro:

Code: Select all

# So wiringPi include files can be found during compile
INCLUDEPATH    += /usr/local/include

# To link the wiringPi library when making the executable
LIBS += -L/usr/local/lib -lwiringPi
Enjoy!
Bill
by bgreat
Sat Feb 16, 2013 2:13 am
Forum: Deutsch
Topic: C/C++ Compiler
Replies: 3
Views: 2609

Re: C/C++ Compiler

Hallo,

Ja, die GCC C/C++ Compiler sind bereits vorinstalliert.

Viel Spaß!
Bill
by bgreat
Sat Feb 16, 2013 2:08 am
Forum: Beginners
Topic: GPIO programming question
Replies: 2
Views: 756

Re: GPIO programming question

You need to call the GPIO initialization and if you are going to use a GPIO pin as an output, you must first set the output mode for the GPIO. #!/usr/bin/env python import RPi.GPIO as GPIO import time # to use Raspberry Pi board pin numbers GPIO.setmode(GPIO.BOARD) # Set pin 11 as an output GPIO.set...
by bgreat
Sat Feb 16, 2013 12:13 am
Forum: C/C++
Topic: getopt() alert
Replies: 6
Views: 2224

Re: getopt() alert

For your example, do you have "c" declared as "int"? I've only seen the problem you describe when "c" is declared "unsigned char". Can we see more of your test code?

Enjoy!
Bill
by bgreat
Fri Feb 15, 2013 8:44 pm
Forum: Python
Topic: buttons and pcf8574 in python
Replies: 6
Views: 9881

Re: buttons and pcf8574 in python

The print format I use shows the value in hexadecimal. You need to test against hexadecimal if you want to try a specific value. Try this: if pins == 0xef: print "Hallo" The "0x" says the following is in hexadecimal. :) Even better, and allowing for multiple key presses: if (pins & 0x01) == 0: print...

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