Undefined Reference Error and Other Questions

[Abhishek]

Magnetic wires have the advantage of creating very dense and compact layouts on a standard PCB, with negligible thickness, as you could see in this picture. However it's not a compulsion, if you do use magnetic wires, remember to check continuity everytime you solder up each wire.

The reason these modules consume different currents is certainly due to backlight LED configurations. This module, as seen from the schematics has 5 LEDs on panel wired up in parallel - but this current and all would make no sense. Had there been an overcurrent issue, the LDO would have been expected to heat up or, the MCU wouldn't be running in the first place! However since you (yellowtiger) are using a 33R resistor, you shouldn't face this issue.

The issue I can say so far has been narrowed down to your wiring. Wire it up, and let us know any further problems you face.

Abhishek

[Tectu]

Ah, I must have missed the part that he already has a resistor in series to his backlight, sorry.
Yeah, wire it up and let us know, meanwhile we pray for you


~ Tectu

[yellowtiger]

You guys are so nice, thanks. I'll try adjusting the FSMC timing first. Then I'll try soldering the wires to the PCB board. I'll let you know how it goes (this might take a few days since there are many pins to solder).

@mobyfat:
I built a toolchain in Xubuntu 12.04 using summon-arm-toolchain and I am using stlink st-flash to flash my program to the MCU board.

[Abhishek]

I'd recommend using the official toolchain from ARM which you can get at launchpad.net/gcc-arm-embedded . Try using that toolchain to build and see if makes a difference.

Also you might wish to try out the Eclipse based IDE ChibiStudio offered by this platform. There is an experimental Linux version. You can read the forum for further info on this.

Abhishek

[mobyfab]

You can try this if you are under linux: http://code.google.com/p/qstlink2/

I made some packages for ubuntu but you better build it from source for the latest version.

Also as Abhishek said you better use the official toolchain as it includes some fixes.

[yellowtiger]

OK, guys, I have tried a few things. Firstly I tried increasing the FSMC delay using Abhishek's code. No luck - Same as before (I have to wait for some time for the LCD board to work). Then I wired my PCB board using magnet wires. I checked continuity after the wiring and the connection looked good. But still no luck.

At this moment I start to think this might be a hardware problem of either MCU board or LCD board. So I ordered another STM32F4Discovery board and another LCD panel. They should be here in two weeks (I ordered the LCD panel from a Chinese seller off ebay). I'll let you know how things turn out.

Thanks again for your help.

[Tectu]

Hello yellowtiger,

So we finally know that FSMC speed is not the issue
Another thing you could try is using GPIO as your LCD interface. The usage of it is documented on the website.
Do you have any way to check the SPI or UART output of the bare F4 ChibiOS example without any LCD? When you don't have any trouble there, it shouldn't be a discovery board issue.

P.S. Where do you life? It always takes me like four weeks to receive chinese ebay stuff



~ Tectu

[yellowtiger]

Hi Tectu,

I do have a USB to UART converter that I, again, bought off ebay. However, I couldn't make it work on any of my three PCs. So for now I don't have a way to check if the SPI or UART output from the STM32F4 board. I have another USB to RS232 converter cable. Do you think I can use this to check?

I currently live in California, USA. It usually takes about 2 ~ 2.5 weeks for Chinese seller's item to get here.

[Tectu]

Hello yellowtiger,

It would be enough when you could tell us if the LED on the board begins to flash immediately after a rest or not.
When it does, there must be an issue in GFX / your LCD (the most likely). If the LED does take a couple of minutes to light up and dosen't flash fast, there is an issue in your toolchain or arround that.


~ Tectu

[Abhishek]

You don't need a SPI analyser to detect SPI output. Simply connecting two LEDs to MOSI and SCLK pins and GND will do the job quite well, unless you don't want to inspect what data you would be getting out of the controller

Abhishek