I have a Netduino Plus with at transeiver attached via SPI. I would like to reset the transiever every time the Netduino restarts. Is it possible to programmatically power on/off the 3V3 pin?
I would recommend using a FET (controlled by one of the I/O) pins to enable/disable 3V3 power to your transceiver. When you say transceiver, I think "more than a few mA" :)
BTW, we took this feedback into account with the new Shield Base module for Netduino Go. It has an integrated FET on both 3V3 and 5V power headers, so you could enable/disable power to your shield in code. Once the new Ethernet go!bus module ships and the Shield Base comes out of beta (soon), your solution can be redeployed to Netduino Go + Shield Base with few/no code changes.
Chris
Secret Labs LLC
Looking at the circuit diagram ( http://www.netduino.com/netduinoplus/schematic.pdf ), I can see only the Micro SD Card Slot having its power controlled programmatically. You could rig up a relay to control it (via a transistor, of course) instead, or if the transceiver uses less than 130mA (the current limit of the device shown: http://www.datasheetarchive.com/BSS84W-7-F-datasheet.html) you could copy the circuit from the Netduino Plus. Buying a relay shield looks like overkill, but you might have other uses for it.
Have you looked into resetting the transceiver programmatically instead of the brute-force method of power-cycling it?
Just to provide another view. You could use a transistor powered off the netduino RESET line, this will reset the device every time the netduino reboots. Or you can just link the transistor to a spare digital pin and power it in code..
What specific SPI device are you using? You mention that it's a transceiver but we could probably provide better information if we know the exact part number. If your device requires less than 8mA the Netduino Plus specs seem to indicate that one option could be using a digital output pin as the power source.
Unfortunately Secret Labs don't use exactly the language I'd expect and call out the sink and source current maximums so I would contact them directly first to see if you risk blowing your chip. I'll see if I can get an answer from them and amend this post if/when I do.
Update: Sink and source current is the same on the Netduino. See my post on their forums about sink vs. source current for a more in depth explanation. So, if your device can run off of just a few milliamps you should be able to use a digital I/O pin to power it.
Also, a lot of devices have enable pins. You can usually reset them with that line instead of pulling the power if that helps. Sometimes with flaky hardware it is better to pull the power though.
Related
I have an existing embedded system with an existing developed C code.
Sometimes the microSD card can lock down giving responses outside of the scope of the existing system.
I'm currently unsure why but suspect the handler in the existing system allows subsequent calls to be made too quickly.
The card is being used in Spi mode to have direct I/O.
The circuit diagram does not show any control over the power to and from the card so I cannot just reset and re-connect to the fresh Spi.
My only option seems to be finding a way to get it to reset through an Spi call, or look at creating a function to recover the sd back to its' expected state from whatever lock it is in.
With that in mind, is there a command or set of commands I can use to cause the equivalent of a reset, or to cancel whatever the microSD controller is expecting?
Looking at the SD associations' specs, the only reset reference is the CMD0 and that isn't applicable once into Spi mode.
Any thoughts are welcome, and thank you in advance.
-Chris
I have a GPS circuit board from china. The only information I can find on this thing is :"amoj GPS 04C www.amoj.com"
It has a serial (DB9) connection and I would like to determine how to putty into it or something.
How can I determine what the port settings that are required to access this?
Pictures below:
Photos in Dropbox
The Jupiter TU60 serial interface is 9600 8N1 by default. The only sentence it will output automatically is the flash checksum message about a second after power up. Google the datasheet for the device and it will let you know about this.
To have it output the position and other information, you must command it to do so. There is a default set of commands that are active after power up. They begin with ## and are from the protocol used by Motorola. Refer to the M12+ Users Guide and Supplement (available online) for information on how to use these commands. I have been able to enter them from Realterm. The only tricky part is calculating the checksum. You can use most hex calculators to do that.
According to the datasheet, the unit goes into survey mode automatically and after about 24 hours goes into position hold. The 1PPS and 10KHz signals are valid to less than a microsecond after a few minutes after power up and to 50nS after a day. I have compared this to another standard I have to verify this. You can use the ##Ea command to get the status of the unit and the M12+ Manual will tell you how to decode it.
Look for $GP... messages at 4800 and 9600BPS as yegorich suggest. Common NMEA messages output by GPS devices are $GPGGA, $GPVTG, $GPRMC.. If you find that data coming out, use Google to look up NMEA 0183 sentence structure and you will have what you need...
I have the same board with the Navman jupiter T Tu60 GPS 1pps 10khz GPS Module on it. I just received my sma antenna and have hooked it up. I am using 12.6V power to the centre pin.
It outputs 1pps on the led with no signal, so that is not to be trusted. Mine is labeled 1pps and 10khz underneath the pcb but these are actually swapped! I put the 10KHz output on my dso and get a 10KHz square wave 50% duty cycle signal but there is ringing on the waveform rise so I have to set the trigger level to 0.8v to get the dso to register the 10KHz frequency. I suspect this may be because the output expects a load and is not seeing one. Now, was I using ac or dc coupling?
I too am getting nothing on the serial. I tried 9600, 4800 using putty on com1 (I have a nice old motherboard) and then tried reversing rx and tx but no luck. As of now I am checking out the serial signals with the dso to see if I can work out what is happenning. I suspect that these boards are rubbish, and useful as power supplies only.
It reads 10.0000 on my hp 5328a counter and sometimes reads 9.9999. It would be nice to be able to talk to the gps to see whether it has satellite lock.
Please let me know how you get on and if you find out any further info.
Brett VK6EZ.
I successfully use WasapiLoopbackCapture() for recording audio played on system, but I'm looking for a way to record what the user would actually hear through the speakers.
I'll explain: If a certain application plays music, WASAPI Loopback shall intercept music samples, even if Windows main volume-control is set to 0, meaning: even if no sound is actually heard through audio-card's output-jack (speakers/headphone/etc).
I'd like to intercept the audio actually "reaching" the output-jack (after ALL mixers on the audio-path have "done their job").
Is this possible using NAudio (or other infrastructure)?
A code-sample or a link to a such could come in handy.
Thanks much.
No, this is not directly possible. The loopback capture provided by WASAPI is the stream of data being sent to the audio hardware. It is the hardware that controls the actual output sound, and this is where the volume level is applied to change the output signal strength. Apart from some hardware- and driver-specific options - or some interesting hardware solutions like loopback cables or external ADC - there is no direct method to get the true output data.
One option is to get the volume level from the mixer and apply it as a scaling factor on any data you receive from the loopback stream. This is not a perfect solution, but possibly the best you can do without specific hardware support.
We have developed an application on Windows.net mobile framework and it is used on a Windows 6.5 Smartphone. for our location based application. Our application is real time and tracks our employees. We are finding that the device loses its GPS signal.
Has anyone managed to restart the GPS receiver so that it starts giving the GPS signal again. I would be ever so gratefull if someone can help. We are using GeoFramework2.0 to deliver the geographic information that you need.
Regards
Sandy
The GPS is "shut down" when no application is using it. Just close your handles and re-open them.
If the GPS on your device is part of the WWAN radio (i.e. cellular phone) it may get put in to a low power state rather than being actually shut off. In that case, you can try restarting the radio.
If that doesn't work, some GPS's will allow you to send proprietary commands to them to force a reset or clear the memory. These commands are not standard and will differ significantly by manufacturer. If you have a SiRF GPS, take a look at the SiRF Binary Protocol Reference.
I'm trying to create an embedded outdoor display of bus arrival times at my university. I'd like the device to utilize my school's secured WiFi network to show arrival time updates determined from a server script I have running.
I was hoping to get some advice on the high-level operation of this thing -- would it be better for the display board to poll a hosted database via the WiFi network or should I have a script try to communicate with the board directly over 802.11? (Push or Pull?)
I was planning to use a Wifly or WIZnet ethernet board in combination with a wireless access hub. Mostly inspired by this project: http://www.circuitcellar.com/Wiznet/winners/001166.html Would anyone recommend something else over one of the WIZnet boards? I saw SPI/UART options and thought these boards could work with an AVR platform.
And out of curiosity -- if you were to 'cold start' this device (ie, request a bus arrival time by pushing the display's on button) you might expect it to take 10-20 seconds to get assigned an IP and successfully connect to the database, does that sound right?
I'd go pull. In fact, I'd have outdoor display make http or https requests of the server. That way the server could tell it how long to show a given set of data before polling for a new one using standard http page expiration.
I think pull would make it easier to have multiple displays, and to test your server as well. I've also got a gut feeling that this would make your display more secure. Someone would have to hack your server to hijack your display.
There's a very cool looking Arduino-targetted product called the WiShield. Seems super easy to use and he provides some source code. It uses SPI for host communication. If you're not interested in going the Arduino route, I'm sure the source code wouldn't be too hard to port to something like avr-gcc. Check it out, might save you some time and headaches for $55. Worth checking out anyway.