Category Archives: PIC32

VGDD SSD1963 EVK R3B w/ PIC32 I/O Expansion w/ USB II and TY700TFT800480

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As mentioned in my last post VGDD now supports a SSD1963 board.  Unfortunately I have the SSD1963 EVK R3B while VGDD was configured for using the Ultima R4.1 board both made by TechToys in Hong Kong.  I figured with enough time to work on it I’d figure it out.

Over the weekend I wired up the EVK board the same way that the Ultima is wired to the FX10A Hirose connector and use that to find the pins on the PIC32 I/O Expansion board.  The EVK board does not include any eeprom or flash chips on them to store touch screen calibrations so you need to supply your own.  As a result of not having that part programmed in yet I disabled the touch calibration until I can work out the correct adjustments to get it working with some form of memory.  My goal at this time was just to get the display working.

After a minor issue where the screen came up blue-tinted but otherwise generally working I kept playing around with the code in VGDD’s XML files and the resulting output trying to figure out what was going on.  A few times it got worse but for the most part it kept working with some type of issue.

Today after getting a few responses from VirtualFab on their brand new forum I started reading through the SSD1963 file to see what was different.  The owner of TechToys has also registered on the forum and he made a few comments about it as well. Armed with a little bit more information it turns out there is a different initialization command format when the Rev 02 TY700TFT800480 board is initialized vs the Rev 03 board that VirtualFab tested with the Ultima and built the XML files for.  After a minute or two I modified the USE_TY700TFT800480_R3 to not include the _R3 and confirmed that it still had the R2 (non _R3) code.  I then enabled an R2 XML file I created with the slightly different Horizontal and Vertical configurations and linked them to the graphics board, disabled the TouchInitialization, compiled, and my familiar roaster splash screen popped back up just fine.

The main difference between the R2 vs R3 LCD panel is that the R3 uses RGB signals while the R2 uses TTL and they are communicating at slightly different bit rates (at least that’s what I think is going on.)  So with that level of progress I decided it would be easier to order some SST25VF016 memory and wire it in to the project rather than to make it work with other memory since everyone seems to be using that same specific chip in their display boards.  It is possible to modify the files to support a Microchip 25LC256 (since I’ve done it in the past) but I figure it’s easier to just FLASH instead.

I’ve had a few conversations with John @ TechToys and he seemed receptive to some of my suggestions about adding some mounting holes to the EVK board so that it can be anchored more easily in a case if you wish to embed it rather than build your own. He also seemed to be considering at least providing a footprint to solder the flash memory to the board if you have it / need it. Since the board needs flash memory to store the touch screen calibration and it’s generally something you do once this will be helpful if it happens. No guarantees but at least it’ll probably be something he’ll think about with any future new board designs.

To wire up a SSD1963 EVK Rev3B to my PicTail Daughterboard I used the following configuration that mimics the Ultima wiring.

SSD PIC32 JP2 PIC32 SSD
TP_XR RB10 1 2 — —
TP_YU RB13 3 4 GND VSS
TP_XL RB12 5 6 VDD VDD
TP_YD RB11 7 8 — OE#
D17 9 10 RD4 WR#
D16 11 12 RD5 RD#
LE 13 14 RB15 CS#
D15 RD7 15 16 RD3 DC
D14 RD6 17 18 RD1 RESET#
 D13 RD13 19 20 RE0 D0
D12 RD12 21 22 RE1 D1
D11 RF0 23 24 RE2 D2
D10 RF1 25 26 RE3 D3
D9 RG1 27 28 RE4 D4
D8 RG0 29 30 RE5 D5
D20 31 32 RE6 D6
D21 33 34 RE7 D7
D22 35 36 RE9 TE
D23 37 38 5V 5V_EXT
D18 39 40 D19

The flash chips and a breakout should be arriving sometime in the next couple days.  The last tracking showed them being in San Francisco and should probably arrive tomorrow.

UPDATE – Flash arrived and I wired it to a generic eeprom/flash board I had made previously using a Radio Shack 276-159B and a SOIC-8 Breakout… wire as follows:

*Note* you may need to wire a 10k resistor to SST25VF016 pin 1/CE#.  Then wire 3.3v to the other side of it.  Mine worked without this done but it should probably be there.  Your mileage may vary.

SST PIC32 SST25VF016 PIC32 SST — —
CE# RD9 1 8 3.3V VDD .1uF Cap GND
SO RC4 2 7 3.3V HOLD#
WP# 3.3V 3 6 RD10 SCK
VSS GND 4 5 RD0 SI

 

Pretty on the outside and ugly on the inside prototype

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So I’ve been busy doing a bunch of computer maintenance and looking into other things I’ve neglected while building the roaster so it’s been a bit slow.  I decided I wanted to start gluing corners together and drilling some holes to see how the case goes together so I can eventually get back to fixing the issues with the roast controller case.  Over the past several weeks I soldered together all of the boards, made wiring harnesses and figured out a bunch of “oops” moves I had made designing things when I got rushed for time.

Turns out I was not able to get stand offs locally in the sizes I had wanted so the heights are all screwed up where I placed holes on the outside surfaces.  I also forgot to specifically allocate power for the exhaust fan in the original design BUT I did have “Spare” pins allocated. The fan I ordered also was not the right size for the hole template I had used (Inside fan dimension vs outside screw / case dimension)… neither of them were actually labeled right the way every other fan I have is sized.

So with everything screwed or harnessed in place this is what I have for the Arduino…

The Arduino wired for Coffee Roaster control

It is a MEGA2560 mounted on a Crib for Arduino.  On top is an Ethernet Shield w/ microSD slot.  Then I used a variety of crimped headers to connect to some of the pins on the MEGA and on the ethernet shield.  I have twenty five lines in the bundle going to the Arduino.  I had some spare 10 strand cables from a project at Halloween and no 25 strand cables to use so I used one of those cable wraps to keep the all together after connecting DB25 to one end and header pins to the other.  Once the lid for the crib for Arduino is in place it then connects to the back of the enclosure.

Wiring Harness connecting to the back of the controller enclosure

As you may notice the sockets I was using for connecting the power out are the type that snap in.  The majority of these will not snap into most laser cut plastic sheets and instead are designed for aluminum cases.  The plug to the right on the other hand screws in.  These work great with a variety of thicker locations.  The fan was originally going to be on the inside with a wire cover on the outside but with the wrong size fan hole in use I had the wrong cover to fit the fans that I had that would fit the hole.

For the DB25 connectors it turned out good that I had decided to use a cut out pattern  that had the holes on the side for the anchoring hex nuts rather than just having them cut out so that I could mount them to the socket and anchor the connector.  Since the stand offs were too short they don’t allow me to anchor the PCBs to the bottom plate.  Instead I had to screw them to the back plate using normal screws and with the burnt circles on the laser cut work I had to use some washers too to keep it sturdy.  This is what the back plate looks like.

Rear Panel of controller

This panel includes – One non-filtered switched 15Amp Power Entry module, 2 snap in 15 amp convenience plugs, 1 5VDC fan, 2 DB-25.  The left one is the main guts for the LCD, TRIAC control, potentiometers, thermocouple, and a variety of other sensors.  The right includes all the non-essential stuff for backlighting all the buttons on the button pad and a few other things including spare wiring.  You cna see just a screw on the right since it was relatively intact and so it won’t block the DB25 plug being used.  The right DB25 has washers and screws in place.  These are primarily used to attached the PCB in place attached to the back side.

Next up is the inside view of the electronics area:

Rear View of the Back Panel

Rear view of the back panel.  I need to shrink up the crimp connectors around the wire  (they shrink like heat shrink tubing but is actually much firmer).  Also the connector on the right side (the switched power entry module) should have the screws more securely fastened with nuts and washers but this is mainly just a test to ensure it all fits together and then allow me to focus on some programming for a while to see if I can get more working and develop menus etc.  The clear acrylic bar is used to anchor the corners better.  I need to change the locations of the screws since I could not find screws the size I wanted without spending way too much for large quantities of them on the internet and having them shipped to me etc.  The thermocouple board on the right had the same issue with the stand offs so it is just floating loose in there right now.  I need to find somewhere to get the Omron thermocouple sockets where I dont need to order them by the 1000s since it looks like Ryan McLaughlin has stopped selling things on his site when they (used to) have problems getting the newer MAXIM thermocouple chip.  They’re all over the place now but he hasn’t restarted his store up so I don’t know the deal there.

Here is the view down into the enclosure from above:

Top view into enclosure

With the cover on:

Front panel installed on enclosure

Front panel running

Front Panel Running

When I send it back out again for a new case I hope to have a different board to install that will be switching the smaller breakout boards being designed onto the circuit board as well as add a power supply and possibly having an arduino board mated on top of the circuit board perhaps to bring more of the electronics inside.  I might want to try to get a Digilent board perhaps to try converting to it as a transition between Arduino and PIC32 before I completely switch to a dedicated PIC32.

I’ve also been looking at possibly creating a dedicated PC application to communicate with it directly via USB and over ethernet.  I am toying around with the “QT/QML” language but havent gotten too far with it.  I may just go back to Processing though.

PIC32 w/ TechToys SSD1963 EVK R3B + 7 inch display and VirtualFab VGDD

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First let me start off by saying…AAAAAIIIIGGGGGGHHHH!  Ok.  I never claimed to be an expert at what I was doing and I’ll have to say this one really made me fight for it.  I have been attempting to get my PIC32MX795F512L USB Starter Kit II attached to a IO Expansion board and then connect that to the TechToys SSD1963 EVK Rev3B board which then connects to the TY700TFT800480 7 inch touch screen.  Then to create my GUI I was using the VGDD software by VirtualFab.it.

I’ve had almost a week now of evenings and several days where I was uninterrupted and able to work on it.  It took a couple of evenings to make sure all the wiring was correct and get all the various parts assembled together for an EEprom to store calibration data to work.  Turns out I needed a bypass capacitor AND NOT to have a pull up resistor on the chip select pin even though it seemed to be used in most examples I found the opposite way.  Once I got past that issue I worked on getting the demo to work which required some tweaking since I was running the demo on a custom configuration that wasn’t a TechToys multimedia board with everything on it.

After finally getting the basic demo working ok I began trying to figure out VGDD’s XML files to add extra Display and Graphics Cards to the software.  I added an entry for each device and then started to customize the individual XML for each part.  After exporting the project and trying to compile it there was of course a LOT of errors.  In a few cases some of the lines got duplicated and in other cases I had to add additional lines or modify the driver slightly to work cleanly in VGDD’s wizard.

I still need to work on a problem where the exported VGDD project has something incorrectly set with the EEprom where the SPI isnt writing so it only shows a single screen and can’t navigate until the touch is calibrated.  Additionally since the SSD1963 is not part of the original MAL (Microchip Application Library) then I likely need to find an alternate place to put some of the files and explicitly map it that way in the VGDD templates.

Due to some previous problems with VGDD (I started using it very close to the beginning of its existence and it has had dozens of releases over several years now) where it seems my files got “scrambled” here and there I would get all sorts of weird issues while trying to compile them.  As a result I’ve started the screens over from printouts and need to figure out how to adjust a few buttons and text as well as add a whole lot more items to many of the menus.

Here’s the awful camera phone photos in a dimly lit room.  Once I get it working better and update the screens more I’ll dig out the better camera. I’m just happy that things are working right now.

PIC32 and SSD1963 board driving a 7 inch touch screen as programmed by VGDD

Test VGDD screen hacked to work on a SSD1963 board with minimal changes.

I’m pretty close to getting the XML worked out so that I don’t need to modify the VGDD code that gets generated but I suspect I’ll need to work on it for a few more evenings before I get it right.

Update 7/24/12 Afternoon – I’ve managed to get the EEprom code to read/write the calibration properly now from the beginning.  I’m seeing an off effect where the OutTextXY functions are not working while all of the static text displays fine and the functions that make it switch screens do not appear to function.  I have one section that defines the touch screen X/Y ADC pins that appears to be a duplicate with something in another section of code that I have to comment out and I have to force it to display a screen since it doesnt seem to happen automatically (may be part of the switching screen problem though).  I’m going to switch to a regular SSD1926 screen and generate code and start comparing because I must have disabled something making the screen objects invalid.  Outside of adding the display a screen command, and commenting out the other code section it does export without a bunch of errors so I am getting further along now.

Update 7/24/12 Evening- I’ve now managed to get straight through compiles to work without having to modify anything.  I had found an issue with the order of the screens where it tried to put one of the “master screens” as the first screen it loads.  For whatever reason this causes it to black out the screen and not show anything.  After switching it to a more appropriate screen it comes up ok.  It also now transitions from one screen to another when I press the buttons as well.  The only issue I’m having is when there is around 30 buttons on the screen it freaks out and stops displaying them.  I’ve been unable to find a notice about there being a 30 button limit but so far I’ve not found a way around it.  The code is all there for all of the buttons but they don’t show up.

PIC32MX795 on a IO Expansion Board connected to a SSD1963 EVK R3B and TY700TFT800480 7 inch touch screen from Tech Toys with GUI created by VirtualFab.it VGDD.

Preliminary PIC32 roaster GUI created in VGDD on a 7 inch touch screen using a SSD1963 controller.

Hey you…Yes you…This is what I’m building…

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I’m focused on building a Roast Controller GUI to automate and track my coffee roaster.  I wanted to document my progress and share as much as possible.  For several months I seemed to spend a LOT of time trying to deal with blog spammers instead.  It’s sort of weird having all these bells and whistles for the blog software.  I’ve got all sorts of filtering tools installed to stop the blog spammers from even SEEING the blog.  Then for the ones that don’t get stopped looking at the blog there’s yet another array of tools to stop known spammers from registering accounts and commenting.  Pretty much on a DAILY BASIS the system automatically kills upwards of over 150 unique IPs trying to spam this thing.  This leaves the rest of you that stop by here and look things over.  I like you guys.  Every so often I get a comment or an email from one or two of you so I at least know some of you come back regularly and a few have even started following on Twitter.  I know some of you are curious what exactly I’m trying to do as my “target” roaster.

If you’ve been around enough to read the older blogs and/or looked in the forum you might have seen some of the parts lists that I’ve purchased on my path to automation.  I’ve mentioned a few tools I’ve used to develop various pieces and I figured I’d show you some of what I’ve been up to… First of all I need to build a “development board” for coffee roasting automation that will be migrated from Arduino to PIC32 eventually.  I’ve had some renderings made of portions of my current “board layout” I’ve been slowly cobbling together.

View showing dual TRIACs and Heat Sink w/ High Voltage Terminal connections.

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Low Voltage pins, position for DB-25 interface to a micro controller wire harness and the control panel socket.

Finally is my favorite piece that I’m eager to get to.  When I can finally get my PIC32 project back up and running I have a GUI mostly built that I need to replace the smaller one with.  I used a tool called VGDD by a guy named Fabio.  His website was found here: http://virtualfab.it/mediawiki/index.php/VGDD:Visual_Graphics_Display_Designer

This product is used to design GUIs for Microchip brand processors.  These include (mostly) the PIC18, PIC24, and PIC32 that can use the Graphics Object Library (GOL).  The Microchip provided tool is pretty much a very crude tool that yields complicated junk that needs a LOT of effort to integrate.  Fabio’s product instead turns the entire process into something pretty simple, allows you to actually write code quicker to control the screen transitions by pressing the buttons and then simulate it (AND send it to other people to review) without ever having to compile it.  It makes the Microchip system quite attractive to create a GUI on.

The great part is with the new GOL 3.0 and some new graphics chips you can create higher resolution GUIs and this development tool doesn’t seem to mind one bit.  One of the screens I built for watching the roast will look like this on the 7″ touch screen.  I cropped a roast curve from one of the logged roasts I made a few weeks ago into the blank space for the graph.  At this time VGDD does not appear to have the chart/graph function included into it.  I’m thinking there’s a way to allocate the space for it in the system but I haven’t really concentrated on it.

Simulated Auto Roasting screen prototype from VGDD.

I figured I needed to clue more of you in as to what was going on and hopefully this helps explain it!

Some of the buttons/controls will change slightly as time goes on but I figured I needed to start allocating space for things as I came up with the ideas and see if it made sense.  As you can see from the date on the GUI mockup there’s been a long time since I started working on that screen.  With the recent Arduino progress I’m feeling like I’ll be getting back to the fancier GUI that will sit on top of the Arduino back end in the coming months.  Eventually I’ll convert some more functions BACK to the PIC32 system since it seems to run faster and can do more of the math faster.  Then I can free the Arduino up to just responding to commands.

Arduino roaster controller with zero crossing dimmer

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With all the time I’ve put into the Pic32 roaster I’ve always had this nagging worry that any of my sensors may have had damage during testing. When you try to get something working and keep getting gibberish you need to find a way to rule that out. As a result I decided to purchase an Arduino a few months back to confirm everything works. Turns out (so far) that everything IS actually working and I didn’t damage any sensors.  In the months I’ve been working with the Arduino I’ve actually learned a few reasons why some of the sensors didnt work on the PIC32 the way I had programmed them because learning to program an Arduino is sooooooooooooooooo much easier and better documented for “average people” to figure out compared to reading the hundreds of pages of technical manual for the PIC32 that isn’t ACTUALLY even finished being written yet.  There is a ton of code out there to test every single sensor I’ve purchased so far on Arduino. In addition I decided it would be a great way to start the dimmer using zero crossing detection in a system that runs outside the PIC32 before I convert it.

My intention is to get basic functions working on Arduino, then get the PIC to talk to the Arduino to send it commands to switch power by itself while the PIC reads all the sensors and logs data and then decides what to do as it comes from the Arduino.  Finally it will eventually be migrated entirely to PIC32 when I learn more about the interrupts on PIC32. At the moment I’ve put together a board that takes in 120VAC and uses Q4015L5 Triacs and MOC3052 drivers to control power to two receptacles. It reads the zero cross on my power using a H11AA1 and gets an interrupt used to trigger power switching. During my initial testing I confirmed the zero cross detection circuit worked and switching the triacs manually on or off worked without  regard to the zero cross state. It unfortunately didn’t seem to actually switch automatically for some reason when I wanted it to dim.  After a few days of testing I realized the Arduino Mega and the Uno had the interrupt timer pins in different places.

Since this is the first mains power circuit I’ve worked on I started running it with a variac out in the garage (and then fed that out into the driveway at the end of an extension cord…) and gradually turned the power up from 0 to 120VAC testing each section as I built it to ensure nothing arced or got hot or burnt up.  During late November I hooked it to the Arduino and got it to begin adjusting fan and heater under PC control as well as using two separate knobs.  Later in December and January I got it to begin logging to SD memory and following a programmed profile.  After that I added a bunch of additional environmental sensors and mounted it in a RadioShack project case.

 

First working prototype in Radioshack Project Case

I’m now at a stage where I’m looking to consolidate the various sensor cards either down onto a circuit board or attached to a set of pins directly.  I’ve grown tired of accidentally unplugging random wires carrying it back and forth from the garage to my office area and out to the kitchen stove / vent at various stages.  My hope is to shrink it down to a much less complicated arrangement being mostly on a single circuit board and interfaced by a few short cables to the Arduino.  It’s a bit complicated currently and getting worse.

Jumble of Arduino stuff

For the Arduino I’m using the MEGA 2560.  It is attached to the power control box pictured above via the DB25 cable.  At this time the box only controls power but I’ve mapped out pins on the DB25 to use for future boards to allow sensor breakout boards from a variety of DIY electronics companies to plug into them.   I’ll break this out to various header pins that match various breakout boards so they can be directly attached.  I’ll probably also design positions for eventually soldering chips directly to a board later once I order them when I’m further along and jumper the headers into those sections.  This will let me test a circuit on the board while still ensuring it actually works with the breakout board first.  The board will be designed to replace the items in the RadioShack box using SMD parts in some cases where cheaper and more convenient to shrink the board down smaller.  I hope to have it all shrunk down and consolidated to a single board with a DB25 connector to get to an Arduino I’ll be mounting inside an Arduino Crib case.

TechToys SSD1963 eval kit on a PIC32 I/O Expansion Board

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Now that I’ve gotten all the leaks taken care of on my new aquarium I decided I should at least figure out if the new SSD1963 eval kit with 7 inch 800×480 LCD that came from TechToys. com.hk works. Officially it is listed on the site as SSD1963EVK-R3B + 7″ WVGA color TFT with Touch Panel Part #: SSD1963EVK-R3B-TY700TFT and as of July 2011 was listed as a bundle price of $119 USD plus shipping. This includes the LCD, SSD1963 board with a cable between them, and 40 jumper cables.

This kit is intended for a development board created by TechToys that fits the connector perfectly. On that board you can then place a PIC32 starter kit. For my purposes this is not usable because I do not need the devices on that board such as the MP3 player. I also need to add a variety of I2C and SPI devices for sensing environmental conditions. For my project sticking with the PIC32 I/O expansion board is the best bet.

I decided I would leave the original breakout boards attached and wire the LCD and graphics chip on. I removed the Microchip Graphic boards from the side and popped out the riser card. To properly find the wiring you need to use you need to consult both the schematic for the Multimedia Evaluation Kit for Microchip PIC32 Starter Kit and the Evaluation Kit for SSD1963QL9. You are looking at the diagrams for MCU interface and SSD1963 EVK Interface. What you will find is that not all of the pins are diagrammed through to both sides. They need wired through though and the correct connections can be determined elsewhere on the schematic. Wire everything from the SSD1963 EVK Interface diagram and then add onto it the Reset, LE and other pins. Once you do this you end up… with a mess:

Then I began the process of trying to compile the modified MultiApp Demo. I selected one of the hardware profile includes for the 7 inch LCD and SSD1963 that involved a PIC32MX795 and tried to compile it. I’ve read about people potentially having to modify when using a Graphics Library higher than 2.0. Turns out this was not the reason I had errors. Instead I needed to fix the driver file because it mentioned parts I was not using and didnt match the name of the driver. I commented out a few lines and uncommented the lines that matched the actual names from the driver. It reports not having a compatible Controller prior to that and worked fine following that. However, the tech toys modifications stopped other graphic apps from compiling so you need to do a diff comparison to figure out changes necessary to newer libraries.

Once the lines were commented out I compiled, uploaded and launched the app. Success was short. Within a few moments I realized while pressing around on the touch screen calibrating the corners and pressing to save the calibration I noticed that the program didnt continue any further. Stepping through a debug I noticed it was at a point waiting for the EEPROM to respond. That’s when it hit me. TechToys sells a development board which happens to include an Atmel SPI EEProm. On the Microchip boards this is found on the graphics board because they expect you to change graphics boards potentially with your own and they supply it on their graphics board.  For TechToys it’s on their development board and not with the graphics boards.

Upon removing the microchip boards I thus no longer have an EEPROM. Upon playing around I found that pressing in the upper right corner instead of calibrating results in the board eventually skipped the write and reload of the calibration and jumped to the home page though I had issues reproducing this reliably. Ultimately just to test it working I ended up triggering buttons about 2/3 of the way from the bottom to trigger the lower buttons and then gradually moving up until it selected another item.  The various graphical items displayed and I managed to get some of the apps to launch though not be able to control them very well.  All that mattered to me is it technically worked as wired.

From what I can see there is an acceptable write speed to the LCD for setting up a coffee roaster control screen but I will need to test further once I can store the configuration data and switch to the original roaster program on the larger screen. I’m thinking I should actually be able to store this to a file on a SD memory stick instead of an EEPRom. Both are SPI but will require a different process to read/write but there’s been others who have done so without much issue into a config.ini file.

More logging… and floating math.

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Two nights ago I managed to finally get the screen that shows graphs to draw the current temperature up in the corner on top of the graph.  Most of the problem was figuring out how to convert the “float” numbers to characters.

I needed to feed this into Microchip’s Graphics Library and accommodate “unicode” characters to get the “degree” symbol on the screen eventually.  Instead of typing a string as string=”Hello There”; it ends up being string={‘H’, ‘e’, ‘l’, ‘l’, ‘l’, ‘o’, ‘ ‘, ‘T’, ‘h’, ‘e’, ‘r’, ‘e’}; which ends up being an array of character values.

A float is a decimal number.  In this case 3 digits for hundreds, a decimal position, and 3 more digits for numbers.  The sensor is kicking out two digits and I’m adding readings together, averaging them, and then rounding up or down with the extra positions in some places.  The PIC32 unfortunately does not have a floating point calculation area in its brain resulting in it “compensating” for it by automatically sliding all the other numbers around using complicated things called mantissa and a few other things I really don’t want to deal with.

The reason I don’t want to deal with them is actually NOT because it is complicated (which it is) but because since it is compensating when you divide a float it has to do MANY cpu cycles for it to compensate and come up with the answer.  It is ACTUALLY easier to multiply the float by 100, 1000, 10,000 etc and insert that number into an integer data type.  Integers can be divided, multiplied, subtracted, etc without worrying about how the numbers line up and doing crazy compensating.  They just don’t end up with a decimal.

If you have a temperature of 175.25 degrees fahrenheit you multiply it by 1000 which equals 175250.  This maintains all of  required digits as a whole number and gives extra space for “rounding” down below.

The issue with the graphics library you need to use a font for every character and take into consideration symbols like degrees etc.  This means it is not simply just a “character” but you need to allocate for all the extra stuff.  This results in a larger space for each character.  To me it looks like a single character in XChar is actually two positions instead of one to leave extra room for the fancy characters to be allowed for.  To convert text strings or float numbers into characters that can be handled by the library you have to load them into an array.  This array to convert the above number (float averaged=175.25)  looks something like this:

int showtemp[8];
showtemp[0]=averaged*1000; //175250

showtemp[1]=showtemp[0]/100000; //175250/100000 = 1 in integer
showtemp[2]=showtemp[0]/10000-(showtemp[1]*10); //175250/10000 = 17.  and then 17- 1*10 = 7 in integer
showtemp[3]=showtemp[0]/1000-(showtemp[1]*100)-(showtemp[2]*10); 175250/1000 = 175 and then 175 – 1*100 – 7*10 = 5
showtemp[4]=showtemp[0]/100-(showtemp[1]*1000)-(showtemp[2]*100)-(showtemp[3]*10); // etc
showtemp[5]=showtemp[0]/10-(showtemp[1]*10000)-(showtemp[2]*1000)-(showtemp[3]*100)-(showtemp[4]*10);

temperaturetext[0]=showtemp[1]+48; // 1 + 48 = 49 = proper number for 1 in character
temperaturetext[1]=showtemp[2]+48;  // 7+ 48 = 55 or proper number for 7 in character
temperaturetext[2]=showtemp[3]+48; // etc
temperaturetext[3]=46; // 46 = proper number for a decimal.
temperaturetext[4]=showtemp[4]+48;  //etc
temperaturetext[5]=showtemp[5]+48;  //etc

 

the results in temperaturetext looks like {‘1′,’7′,’5′,’.’,’2′,’5′}

I roasted twice now using the new graph with actual temperatures listed up top and was planning on comparing the results but I accidentally corrupted the first file.  I’ve got one more batch of some coffee from Rwanda that I was testing with.  I’m getting pretty close to running out of coffee again so it’s time to order some more soon.  I was hoping to have something good from Ethiopia come up for sale but it’s still a little early for that.

Still working on… recognizing temperatures for various(rough) stages the roast is at vs some sort of mechanism to confirm a stage marking things like first / second etc.  Also need to get ambient weather information recorded and get other sensors going on it…. and make it pretier…. and of course get it hooked to higher voltage turning on and off the heat.

Writing to SD memory…

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Soo… the latest update… I had wired in the SD memory stick reader and had been testing it separate from the main roaster program. I’ve found having a “dedicated” programs for a particular sensor with the rest of the sensors and displays attached but not initialized has resulted in easier testing and troubleshooting.  Occasionally it works right away but other times conflicts come up.  Generally once I have manage to confirm it works without the other code running I at least have a reasonable assumption that it may actually work and is wired properly.   Since I’m pretty new to the whole wiring these things up it’s a pretty good idea to test my wiring out.  So far I’ve actually done pretty well reading enough about each sensor to figure out what I need to make it work the first time.  If I go too long not getting it to work I try to disconnect everything else and run it by itself which usually helps me identify conflicting pin usage that I didn’t see initially.

So far I tend to find issues with the LCD interface / graphic chip / memory config chip to conflict with a particular pin here and there.  If it works without the LCD boards attached it obviously has a much smaller number of pins from the new sensor to try to find a conflict with. Usually by the time I isolate the LCD away from the system I’ve managed to throw together code that works within minutes of starting things up again.
My last success with the SD memory was short lived because I discovered there were pins that I had not noticed on the SSD1926 that apparently do something even though I’m in 8 bit mode instead of 16 bit.  They seem to have ended up being connected when I was trying to check my Write Protect and Card Detect pins.   It took probably about 3 hours of looking at the schematic for the graphics board assembly to figure out which wires (15 minutes) it was and then find some (the rest of the time) that were not being used already.   Since I am using 8 bit communication instead of  the 16 bit mode I would have assumed them to be “dormant” and potentially available.   Not quite sure what is going on with that since I have not obtained the data sheet for the SSD1926 chip yet.

I had an unexpected guest show up early in the week and didnt get much time to work on this.  After making a few adjustments to the wiring I got it up and writing to the SD with the LCD attached.  This weekend I got it loaded inside the Coffee Roaster programming.  I ran into a few initialization problems that resulted in a momentary “stream of gibberish” coming out the UART port that I was using for watching status of some of the code I was troubleshooting with in a terminal window.  It seemed as if the system had a baud rate to the com port of the computer that suddenly “shifted” up and down a few times in the middle of the machine starting up and then returned to normal. After I removed some of the apparently duplicate excess code from the init area it resumed working normally.

I then had to move the “write to SD” down through the startup past the time and date retrieval area.  This results in accurate time/date stamps on the file now being written to the SD memory card.  I then began to modify the SD demo write into a command that builds the buffer data using a sprintf template inserting date and time on a line separated by commas and a few sections (with 0.00’s right now) for sensor data as well.  I’m going to bundle the write commands up into a function so that I can insert it into roaster loop as a external function.  Every time it samples the temperatures and other future sensors it will shove it into the call to the “write to SD” function where it will get formatted and append to the file it created during the initialization of a new roast loop.

As I said, I havent had much time to work on it this past week but probably tonight and tomorrow I’ll get significantly closer to figuring that part out and probably test running the roaster with nothing in it just to get some temperaturee logging as it goes up/down for a few seconds and then exit the roast to close it to check the accuracy. Then when I’m sure that’s working I’ll try to do a regular roast with it out in the kitchen and see if I can get “good numbers” that I can post.

If I can get that working then the next step will be to get a “file management” function going to come up with names of files to make them unique and maybe let me load the data into the system to preview it on a graph on the PIC32 LCD as well as delete files. THEN I get to start figuring out how to program it to control things by itself based on my normal data.  😀

Close Encounters of the SD Memory Kind…

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Sooo generally annoyed with sensors I decide to take a different direction, SD Memory.  Fun things happen with SD Memory.  You rip one open and you’ll usually find a single little flash memory chip and some other chip in front of it.  I haven’t identified the “guts” yet but that’s not really important.  What’s important is that generally you talk to that little flash memory chip using SPI (usually unless you wanna pay for licensing fees to use the direct SDIO method it sounds like.  Crazy licensing costs = faster SD Memory.  Free method = slow access.  If you need every bit of speed you can get then you’ll likely need that expensive method.  If you can buffer up data internally and then write it out later then you’ll use the SPI method).  This is likely to be preferred to have a built in memory chip to buffer items up just like working with a document on your computer.  It then isn’t until you save the file that it then transfers it from the internal memory out to the SD memory for transportation to the PC.

There is not much to it other than that except for having some structures that issue a few reads and writes to find a spot on the chip and make a file name and fill the file full of stuff.  That portion is the “FAT” portion that makes you able to read it on a computer etc.  This slows things down considerably in an SPI Method.  Apparently people have experimented with reading/writing to the SD memory chip with no

After a few days of poking at it and moving a couple wires around I’ve now managed to get it to make a file… and I can see that file on a PC.  The problem is I can’t get it to put anything INSIDE the file.   It just keeps getting stuck on the portion where it’s expanding the size of the file…  further it’s been quite a pain that any SD memory sample code out there is written focused on the 3xx series PIC32 and from looking at the various forums my issues are pretty common.  Most people get the 3xx series working just fine.  Many people seem to get files with no contents on 6xx and 7xx series PIC32s.

The only published successful people I’ve found seem to be commercial product developers who don’t want to share any code samples clarifying how to handle the failures properly.  The only exception I’ve found was some code modified by the user bmorse on mypic32.com.    His code appears to be modified to work specifically at 60mhz and using SPI2 which worked for initial testing to ensure I had things wired properly.   I needed to put a pull up resistor on the CS and the DO of SD to SDI2 on PIC32 and everything started working properly.

I’m now trying to isolate the portion of the code that affects the timing to increase the system speed back up to 80 mhz and scale the SPI back down again.   To assist in this department I’ve procured a FT232 UART to USB Com port chip on a breakout board from SparkFun.   This board is commonly used to take the UART output of various text and data from the running PIC and interact with it in the terminal window instead of watching the raw data on the debug watch.  I’ve learned that the watch window often “messes up” a lot of SPI states by constantly inspecting the information.  The idea is that it interrupts the normal state (data waiting etc) flags due to having read it for the watch window  blocking the rest of the circuit from detecting it.

I’ve also obtained a DS3234 clock.  At time time I only have the one I2C DS1307 clock and I may wish to eliminate the I2C bus unless I come up with something else that needs it.  Even if I use I2C elsewhere it seems as if 5 volt I2C is more of a rarity meaning I can’t really use that bus for other things anyway.

User interface work.

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So at this point I’ve gotten annoyed with the other temperature sensor and decided I might as well move ahead with the functional part of the roaster.  This means the first thing I needed to do is draw a main menu for options.

Main Menu

As you can see this lists Manual and Auto Roast.  My plan is to make it where the first option simply gives you a few readings and then lets you “drive” by sliding the controls around.   I would make it log the information of what you set things to and what you got back from the system and perhaps let you “store” the settings to play them again as a profile.  That is where the next phase comes in, the Auto Roast.

I expect Auto Roast to be a portion of the system that would let you choose to either A) load a previous profile, or B) let the roaster pretty much run itself using a basic model of “drying” at a lower temperature for the first few minutes at a high fan speed and then begin to lower the fan speed and raise the temperature responding based on the time into the roast vs the temperature.  Expectations of driving first crack and the end of the roast based on a desired result would vary how it would work.  I’d anticipate some sort of yes/no 1/2/3/4 etc sort of question and answer series immediately before the roast activates.  While it would be mostly automatic you can step in at any time and seize control of a particular setting.

Main roasting screen

At this time the roasting system only monitors.  I have yet to work on actually connecting it directly to any of the controls on the roaster.  This will come later when there are more and better controls implemented.  Currently it simply shows bean temperature in Fahrenheit.  I will add the option to switch the temperatures on the Settings option from the main menu.  It also has a slighly inaccurate timer.  It seems to gain a second or two over the system clock in the corner every 40-60 seconds.  I need to work on the prioritization of the interrupts in the system and implement a series of if/else and/or case statements where I can service temperature, screen updates, and time tracking and use all of those checks as part of the delays required reading various sensors etc.  For example if it takes 100ns to service one sensor telling it to read a temperature or something but I need to wait 100ns to do another function then I can initiate the read request, perform the other function, and then return at the end to pickup the temperature result.  Some functions are more critical so they will take priority over other functions.  Those functions will take place on a tighter schedule while the other functions will “squeeze in” anywhere they can and take place based on a “true/false” tracking of whether they’ve run recently.  Once everything has run then everything will reset and things will start looping again.

The roast control system also has a series of buttons down the bottom for returning to the main menu, adding or removing time from the timer, as well as buttons for heat and fan control.  I expect to put more sensor readings as time goes on to display on the empty space.  I’m hoping to get the fan and heat controls to pop up over top of the roasting screen, allow adjustments, and then drop back to the bottom “tray”.