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

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?

@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?

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?

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

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?

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?).

This is strange. Out of curiosity is the USB cable disconnected while taking these measurements?

So what we need to measure is the (1) input to the 5V regulator (should be about 8.7V), (2) the output of the 5V regulator (should be 5V when not powered by USB), (3) the voltage on the output side of the MOSFET load switch for the 5V header (should be around 4.95V), and (5) the voltage at the LCD (should be around 4.9V or more if you have proper cabling). When making these measurements your reference should be the power supply input negative terminal at the input barrel connector.

I'm surprised that the voltage output of the 5V regulator is so low.

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.

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.

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.

These are 5V displays, too. Therefore, you will need 5V pull-ups on the I2C lines. When you get the display you will need to solder a 0 Ohm resistor or something (piece of wire or bridge it with solder like I do) across R1, see page 4 of the datasheet...

 

http://www.newhavend...Z-FL-GBW-V3.pdf

 

And yes I will post some code tonight for this display. I have a driver for it on my PC at home. Will post it tonight.

I live in the US. I think you will learn more by me walking you through the steps of troubleshooting the hardware. Even if you are only interested in software. A software person with good hardware skills is very desirable.

 

Anyway, let me do some testing on my Netduino Plus 2 tomorrow and I will get back to you with some things to try.

Are you making any progress Frank?

Ok, I looked at that display for a bit and it uses a parallel type display with a I2C gpio expander. Also, it is a 5V display so you would need to ensure that you are powering it from 5V and that the I2C pull-ups are to 5V. If you are new to METMF and Netduino I would suggest going with a true I2C serial display such as one of these...

 

http://www.newhavend...lays-c-253.html

 

Although the Arduino library can be ported to NETMF, you will be better off going with one of the displays I have pointed you to. With NETMF not being a real-time environment you might run into issues with the timing on this display anyway, especially in a multi-threaded application, but I'm not for sure. Another option is to use an Arduino instead of a Netduino. Sorry I couldn't be more helpful, maybe someone with a little more free time and ambition will come by and port it over for you.

Looking at the Netduino schematics I think it should more than capable of providing the LCD power without a large voltage drop...that being said let's figure out what is causing your 0.4V voltage drop and then we should be able to fix it. Please measure the following voltages...

1) VIN_PROTECTED (U1 pin 3 on Netduino)
2) +5.0V (U1 pin 4 on Netduino)
3) +5V_HEADER (at the connector on Netduino)
4) VDD (at the LCD input connector)
5) SDA/SCL (idle voltage)

Make these measurements with your 1500mA power supply connected to the Netduino and the LCD power, ground, SDA, and SCL pins connected to the Netduino connector.

I cannot find that display. Can you send me a link to the website you bought it from?

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