I figured out the problem. I accidentally assigned an inputport to one of the serial port pins on the Netduino. Getting rid of that line of code fixed my problems.

Can anyone tell me if the netduino 2 has a problem using two serial ports in an application. I have each working fine on their own. However, when I tried to open both in an application I get an exception on the serialport.open() of the second one. I have tried everything. Please help!

See this post. It seems you are correct and the pins are labelled wrong...

 

http://forum.arduino...c,209133.0.html

@Chris Walker and Secret Labs

 

Any chance we could see a Netduino with a powerful micro like the LPC4357? I would really like to see a Netduino with a 24-bit LCD port. Although, the hardware cost would be higher, it would be cool to see a port for the Intel Quark processors, too.

 

How difficult is it to port NETMF to a new processor?

The LPC4370 is a 204MHz M4 with 2x 204MHz M0 cores and 264kB+ RAM. And the quad SPI interface makes it easy to add Flash. Although for an LCD capable board one would need to add external RAM and Flash anyway. It just seems to me to be as good or better than anything ST Micro has to offer and a perfect match for NETMF. But that is just my opinion.

But I understand that there is a lot of reasons to stay with the STM32F4 family, as Cuno has pointed out.

I have been using the GHI EMX Development System for a couple years but I am just disappointed with the performance. I'm surprised there isn't a lot of competition to that yet. I haven't tried their newer module base on the LPC1788, though. I will have to look more into

Chris the reason I am looking for Netduino to offer the product is for the NETMF display stuff to be implemented . Is Secret Labs planning on implementing this in the near future?

Why does the Netduino disconnect and reconnect several times when I start a debug session? It will eventually start the debug, but up to that point Windows shows the Netduino being dettached and reattached 3, 4, 5,... times before it goes. Any ideas?

Yes, I have the custom board working! Thanks for your help! And if you are curious about my issue...

 

The processor wasn't recognizing the attachment of the USB cable after the firmware was loaded. I measured the VBUS signal to the processor and realized it wasn't getting pulled up high enough due to the 100 Ohm series resistor I used. Removed the resistor and problem solved. Looking at the datasheet for the STM32F405 shows the internal resistor divider on the VBUS signal is fairly strong and explains the problem.

Can you provide all the files needed to load a custom board with Netduino firmware / bootloader. When I load this DFU in the STM32F405 and reset the board, I cannot access the device through MFDeploy. Is there another file I need to load?...tinybooter, tinyclr, or something?

I found all three of the files (tinybooter, flash, and config) in the NetduinoUpdater zip folder.

Thanks Chris. So if I use the same crystal frequency on the Netduino board I shouldn't need to recompile anything, right? I was able to successfully use the STDFU to program my hardware. And when it powers up I know it is doing something as the LED will turn off after a few seconds. However, windows will not recognize the MCU when I plug it in unless it is in the bootloader. Can you provide the Tinybooter and Tinyclr files for the Netduino? Thanks again for your help!

Does anyone know the significance of having BOOT0, PB11, and PC14 tied together? I understand why BOOT0 is pulled low and has a switch, but why PB11 and PC14? Do they just need to be pulled low when unused?

Awesome, glad I could help! Also, please mark this topic as "answered" if you can.

I have used all address combination

A0, A1 and A2 are not soldered, so i think the address if 49, but i have tried last address 4F, because i wasnt sure..so it must be the last or first address.

 

Ah, I believe that is your problem. See page 4 of the datasheet...

 

http://datasheets.ma.../en/ds/LM75.pdf

 

It states that the address pins A0, A1, and A2 should "not be left unconnected". Tie them all to ground and set the address of the device to be 0x48. Hopefully that will work for you.

 

As far as the pull-ups go, you are probably fine if the pull-up resistors exist somewhere on the bus...i.e. on the LCD module. Especially since the I2C bus is working for the LCD.

 

Keep us posted.

Can you describe what is happening? ...are you seeing "LM75 is not responding..." printed out, or are you getting an exception thrown, or is the temperature reading not right? As gismo said verify pull-up resistors and also check the address of the device (is A0 pulled HIGH, and A1, A2 pulled LOW?).

Since the "device.Execute(...)" is returning zero, that tells you the LCD is not acknowledging the I2C commands. Double check that the SCL and SDA lines aren't crossed. Also verify that the power to the LCD from the Netduino is greater than 4.7V. If it is not you will need to power the LCD from its own supply/regulator.

Yes...you will have the power supply V+/V- wired up to VDD and VSS of the LCD, and the Netduino will need have SCL, SDA, and GND wired to the LCD.

If you use an external power supply for the Netduino (such as the one below) you will only need to use USB for debugging as you have stated. The power supply should be connected to the barrel input jack. Be sure to ensure that the power supply has a positive center barrel (this is most common type).

 

http://www.mouser.co...bXAYafurk4XukHd

I guess it just occurred to me that you are probably powering your Netduino from USB. That being said, if you have a power supply around (+7.5 to +9V DC, >500mA output) you could power your Netduino from that and may not need to wire up the LCD separate. If you have a power supply around that would be a quick test.

Also if you do not have the right sized barrel on the power supply, you could wire it up to VIN and GND pins of the Netduino connector. Make sure the voltage of the supply is between 7.5VDC and 9VDC, though.

Are you making any progress Frank?

Yeah, the voltage may still be too low. You should power it up from its own supply. Also make sure you are checking the return value of the I2C execute commands...that will tell you if the LCD is acknowledging the commands.

Here's a few things to check...

 

1) Is there a jumper / short across R1? (R2 should be left open)

2) Measure the voltages of SDA and SCL while the bus is idle...are they pulled up to 5V?

3) Try adding a delay at the beginning of your code to ensure LCD is up and configure ("Thread.Sleep(1000);")

4) Step through the code using the debugger and ensure the "device.Execute(...);" functions are returning a non-zero value. You will need to change the code slightly... "int ret = device.Execute(...);"

5) Try setting the brightness and contrast..."display.SetBrightness(0x07);" ... "display.SetContrast(0x30);"

 

The Netduino should be capable of providing the 250mA to the display, but you can verify this by measuring the voltage at the display when it is plugged in. If the voltage is above 4.7V it is fine.

What is the part number of the LCD you are using. This may help us help you. If it is a Newhaven Display serial LCD then you need to install an on-board jumper to configure it in I2C mode. Your fix probably isn't that easy but just thought I'd throw that out there. Also, if you give me the part number I could write you a simple piece of test code.

For the [latest versions of] Netduino 2 and 2 Plus you should connect the I2C lines to "SC" and "SD" as you are doing. What is the voltage to the LCD?

So to make sure I understand you correctly, when you measure the 5V output of the Netduino without the LCD connected, the voltage is 4.68V...and with the LCD connected it is 4.23V?

 

If this is true, you must supply the LCD with its own 5V power supply. Do you have an old USB cell phone charge? If so, cut the connector off and wire it up to the LCD for 5V supply.