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by tedhale
Wed Nov 21, 2012 4:13 pm
Forum: General discussion
Topic: Which (if any) GPIO pins can trigger a hardware interrupt?
Replies: 4
Views: 1003

Re: Which (if any) GPIO pins can trigger a hardware interrup

A recent edition of the MagPi explained how to do this from Python.

http://www.themagpi.com/
by tedhale
Wed Nov 21, 2012 4:09 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: CTS, RTS & DTR in hardware?
Replies: 6
Views: 7008

Re: CTS, RTS & DTR in hardware?

No. It has only TX and RX.
If you need hardware handshaking, you will have to use a USB-Serial adapter.
by tedhale
Mon Nov 19, 2012 2:18 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Disable UART / serial console to get max GPIO's
Replies: 13
Views: 20090

Re: Disable UART / serial console to get max GPIO's

It turns out that my old CM11a wasn't dead. The cable was just so worn out that it wasn't making good contact. I now have a shiny new one ($39 on eBay) that works even when I shake the cable. Found that my test using the DB-9 tester is meaningless. A good CM11a will also fail to light up any leds. O...
by tedhale
Wed Nov 14, 2012 3:07 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Disable UART / serial console to get max GPIO's
Replies: 13
Views: 20090

Re: Disable UART / serial console to get max GPIO's

It appears that my ancient CM11a interface has finally failed. :cry: I connected it to a Black Box DB-9 Tester (simple in-line device that has green/red LEDs for all the lines) and it showed no life. Normally, when this device is plugged into a serial interface, at least the TX or RX line will light...
by tedhale
Wed Nov 14, 2012 3:01 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Disable UART / serial console to get max GPIO's
Replies: 13
Views: 20090

Re: Disable UART / serial console to get max GPIO's

Thank you for your hint, i will have a look at it. At the photo of your blog, wich wires you are using? I never found them in the internet to buy them. Greetings, Sebastian I suspect you are referring to the wires that I used to connect from the GPIO ribbon cable to the breadboard. Those wires can ...
by tedhale
Tue Nov 13, 2012 9:07 pm
Forum: Debian
Topic: is it possible to pause the boot process for 5 minutes?
Replies: 6
Views: 6281

Re: is it possible to pause the boot process for 5 minutes?

Out of curiosity - why?
by tedhale
Tue Nov 13, 2012 9:06 pm
Forum: General programming discussion
Topic: how do you do it
Replies: 11
Views: 2130

Re: how do you do it

philoponeria wrote:On a scale of 1-10 If i wanted get one of these things and use it as a media server how much programming "stuff" do I need to learn?
None. It has already been done. Search for xbmc or OpenELEC
by tedhale
Tue Nov 13, 2012 9:03 pm
Forum: C/C++
Topic: C vs Python for GPIO
Replies: 27
Views: 22180

Re: C vs Python for GPIO

Well, any C library is usable from C++. And you use them exactly the same way you would in C... Almost. The calling sequence is different. One big reason is that C++ allows multiple functions by the same name to have different parameters. To call a C function from C++ you must use extern "C" Many l...
by tedhale
Tue Nov 13, 2012 1:51 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Disable UART / serial console to get max GPIO's
Replies: 13
Views: 20090

Re: Disable UART / serial console to get max GPIO's

I quick search found this

http://www.smarthome.com/manuals/protocol.txt

Which says that RI (an input to the RasPI) is needed, which doesn't really make sense.
This is going to take some experimentation.
I wish I still had an RS-232 breakout box.
by tedhale
Tue Nov 13, 2012 1:45 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Disable UART / serial console to get max GPIO's
Replies: 13
Views: 20090

Re: Disable UART / serial console to get max GPIO's

I tested it again last night and it does not work. It appeared to work with my software, but it was never actually outputing anything. I downloaded and built "heyu" to test it and it failed also. This is probably due to needing to have hardware handshaking. I don't believe that a fully functional RS...
by tedhale
Mon Nov 12, 2012 8:05 pm
Forum: Advanced users
Topic: Connecting RPi directly to PC ethernet port
Replies: 38
Views: 81966

Re: Connecting RPi directly to PC ethernet port

Everyone seems to be missing the fact that the OP said he is connecting the RasPi DIRECTLY to the PC. No switch, hub, router, etc. is involved. With that set up, you can use any any IP address you like as long as both systems are on the same subnet. (with the caveat that if the PC has WIFI, don't us...
by tedhale
Mon Nov 12, 2012 7:51 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Serial & C Programming
Replies: 17
Views: 4290

Re: Serial & C Programming

The open is failing because the OS is using that port by default. On boot it outputs status info After boot it allows a user to logon. Look at my blog post http://raspberrypihobbyist.blogspot.com/2012/08/raspberry-pi-serial-port.html There are instructions on how to stop the OS from using the serial...
by tedhale
Mon Nov 12, 2012 4:10 pm
Forum: Automation, sensing and robotics
Topic: Home alarm system retrofit.
Replies: 36
Views: 20482

Re: Home alarm system retrofit.

Yep. I use two levels of alarms. Door switches and motion detectors. The motion detectors will remain on for a pre-defined period of time once triggered, so there is no way that a program in Python would miss that. Plus, they have to do this without making my dog bark. Good luck with that. She even ...
by tedhale
Mon Nov 12, 2012 3:55 pm
Forum: Advanced users
Topic: Connecting RPi directly to PC ethernet port
Replies: 38
Views: 81966

Re: Connecting RPi directly to PC ethernet port

As the above post points out, DHCP only works when there is a DHCP server on the network. Since you are connecting the Pi and the PC directly, there is no DHCP, so your PC does not get an address. You will have to set your PC to a static address. Also, if you have a wireless connection on the PC, be...
by tedhale
Mon Nov 12, 2012 3:39 pm
Forum: Off topic discussion
Topic: What are your Other Hobbies / Interests??
Replies: 72
Views: 10932

Re: What are your Other Hobbies / Interests??

I'm also a HAM (KJ4CEX) but I am not very active. I only use 2M and have it for emergency use. I volunteer for Amateur Radio Emergency Services for my state.
There are quite a few amateurs getting involved with the RasPi.
by tedhale
Mon Nov 12, 2012 3:36 pm
Forum: Automation, sensing and robotics
Topic: Home alarm system retrofit.
Replies: 36
Views: 20482

Re: Home alarm system retrofit.

Polling GPIO with Python is fine if the signals you need to read do not change too quickly.
If you poll using C, you will see several orders of magnitude increase in speed. (or far less CPU used if you throttle the polling.)
For a home alarm system, Python should be OK.
by tedhale
Mon Nov 12, 2012 3:31 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Disable UART / serial console to get max GPIO's
Replies: 13
Views: 20090

Re: Disable UART / serial console to get max GPIO's

I am pretty sure that the CM11A did work with just the TX and RX lines used. It has been a couple of months but I am pretty sure that it did test out OK. I have been working in my (rare) spare time to finish the complete interface board, so I haven't been using the serial port for a while. My SPI bu...
by tedhale
Fri Nov 09, 2012 5:41 pm
Forum: General discussion
Topic: Stress testing a RPi
Replies: 7
Views: 4143

Re: Stress testing a RPi

It is also possible to connect a serial port (adafruit has one that is simple to connect) and logon to the Pi that way.
by tedhale
Fri Nov 09, 2012 5:34 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Disable UART / serial console to get max GPIO's
Replies: 13
Views: 20090

Re: Disable UART / serial console to get max GPIO's

look here http://raspberrypihobbyist.blogspot.com/2012/08/raspberry-pi-serial-port.html It is about my work to set up a serial port using those pins, but I describe how to disable the system use of the serial port. Follow those instructions and those two pins will be available for use as GPIO. That ...
by tedhale
Thu Nov 08, 2012 8:29 pm
Forum: Beginners
Topic: Iptables restore
Replies: 4
Views: 2990

Re: Iptables restore

No problem. We expect noobs here. We were all there once. I just wish that forums like this were around when I started years ago, but that was before the internet was very common. Do this: sudo nano /etc/rc.local sudo makes the command run as root (required to edit this file) nano is a text editor
by tedhale
Thu Nov 08, 2012 1:59 pm
Forum: Beginners
Topic: Mounting USB Drive
Replies: 6
Views: 2214

Re: Mounting USB Drive

If it came pre-formatted, then it is probably FAT32 file system.
Windows could create an NTFS system, but I think it defaults to FAT32 for removable media to improve compatibility.

Try vfat as the file system type.
by tedhale
Thu Nov 08, 2012 1:47 pm
Forum: Beginners
Topic: Iptables restore
Replies: 4
Views: 2990

Re: Iptables restore

Just put the two iptables commands into /etc/rc.local and they will be run at the end of the boot up process. I use an ubuntu system as a firewall with extensive iptables rules ( a couple hundred or so) I created a firewall script that gets run from the init process and reads most of the setting fro...
by tedhale
Thu Nov 08, 2012 1:38 pm
Forum: Other projects
Topic: Battery Problem For Cool Kids Only!
Replies: 25
Views: 5042

Re: Battery Problem For Cool Kids Only!

The article in the MagPi points out an important issue when using batteries - the efficiency of the voltage converter. If you just need to show that this will work, then it's not too much of an issue. However, if you really need to run this on batteries for an extended period of time, the efficiency...
by tedhale
Thu Nov 08, 2012 1:18 pm
Forum: RISCOS
Topic: !RDPClient not working with Server 2008 R2
Replies: 7
Views: 3430

Re: !RDPClient not working with Server 2008 R2

OP says he can connect from other systems, so yes RDP is running on the server. First thing I would check is the RDP authentication level required. You need to check the box "allow connections for clients running any version of remote desktop" Server may default to "only allow clients that use netwo...

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