Driving the single chip was a fun code experiment.  So let’s look at that.  Like I said on the Stock Bot page I had to learn (re-learn/hack in) C# for this.  When you drive the chip you are essentially sending it a binary code along 4 digital lines.  A 4 line data bus I guess.  Given an integer from 0 to 9 convert that to binary or otherwise figure out how to set your 4 data pins correctly.

A set of if statements would do that.  A switch statement would do that.  Both I tried as I had to get something started.  Neither felt clean enough to me (don’t get me wrong some of the code is still way to ugly to even tell you about yet/ever).  So I worked out what I have below because I knew in my mind something cleaner should exist.  Your improvements are welcome as comments.

    // helper class
    class BCDOutputClass
    {
        byte mask1 = 1;
        byte mask2 = 2;
        byte mask3 = 4;
        byte mask4 = 8;

        OutputPort Bin1 = new OutputPort(Pins.GPIO_PIN_D9, true);   // A
        OutputPort Bin2 = new OutputPort(Pins.GPIO_PIN_D12, true);  // B
        OutputPort Bin3 = new OutputPort(Pins.GPIO_PIN_D11, true);  // C
        OutputPort Bin4 = new OutputPort(Pins.GPIO_PIN_D10, true);  // D
        OutputPort CommaPin = new OutputPort(Pins.GPIO_PIN_D13, false);

        // Constructor
        public BCDOutputClass()
        {
            //
        }

        // Instance Method
        public void Display(byte a)
        {
            a = (a < 10)? a : (byte) 10;
            Bin1.Write((a & mask1) > 0);
            Bin2.Write((a & mask2) > 0);
            Bin3.Write((a & mask3) > 0);
            Bin4.Write((a & mask4) > 0);
        }

        public void Clear()
        {
            Display(10);
            Comma(false);
        }

        public void Comma(bool a)
        {
            CommaPin.Write(a);
        }

        // Destructor
        ~BCDOutputClass()
        {
            // Some resource cleanup routines
        }
    }

Most of this becomes clear if I just talk about the meat of the code in public void Display(byte a).  Maybe not but let’s start there as it is the crux of what makes this (IMHO) better over an if or switch statement.  I have, of course, not tried to figure out if this compiles to smaller code or not – that’s not a concern I have any interest in yet.

The function takes in a byte – the code when running sends in the values zero to 10 when all is normal.  10 is an exception and I should explain that first as the line first executed is a test for values over 10 and if over we revert a to 10.  10 in binary is 1 0 1 0.  Setting the 4 pin data bus to an invalid value.  1 0 1 x (where x means it’s not important) happens to BLANK the display.  This make the code in the function public void Clear() fairly obvious now why it send a 10 to Display().

The 4 pins how do they get set?  ok, let us use the digit 9 and now step through the rest of the function.  Pin 9 on the Netduino is connected to A or D0 on the 4511, the lowest order bit (ones). 12 is to B or the twos, 11 is to C or the fours and pin 10 to D the highest order bit the eights.  You can look to the mask declarations to get a feel for the positions too.

9 is binary 1 0 0 1

We need to set line A to true, line B to false, line C to false and line D to true.

(a & mask) what does that do?  ”a” is type byte and mask1 is of type byte.  The & says do a bitwise AND of the two values.  What’s a bitwise and – (for now – Google it) but I’ll do the math here and might get it across.

1 0 0 1  (9)
0 0 0 1  (mask1)
-------  bitwise and says 1 only when all are one
0 0 0 1 (1)
Result = 1

1 0 0 1  (9)
0 0 1 0  (mask2)
-------  bitwise and says 1 only when all are one
0 0 0 0 (0)
Result = 0

1 0 0 1  (9)
0 1 0 0  (mask3)
-------  bitwise and says 1 only when all are one
0 0 0 0 (0)
Result = 0

1 0 0 1  (9)
1 0 0 0  (mask4)
-------  bitwise and says 1 only when all are one
1 0 0 0 (8)
Result = 8

Let’s take the results of the first operation.  We got a 1.  There’s more in that line of code (a & mask1) > 0

Greater than zero completes a comparison.  Results in a boolean.  True or False.  The first part will result in a zero when we need a false result and a true value when the result is anything else 1 or above.  In the case we just ran through we had a 1 and an 8, both greater than zero, and so had two lines (the first and last) set to true.

By now you’ve either gone Aha! or Duh or are scratching your head.  Either way I am done for now enjoy.

Free learning – if you have kids – create accounts now. This will help every kid and you’ll be sorry if you don’t also sign up like I have and sharpen you skills.

http://www.khanacademy.org/

The first 15 minutes of this podcast prove to me that the more math you can take in the better off you will be in life.

http://media.grc.com/sn/SN-034.mp3 100% relevant regardless of when it was recorded.

Now for those of you at the back of the class the zbot botnet has been augmented to shoot phish in a barrel.  You are the phish unfortunately.  Thank you Visa for the swimming lessons (NOT).

Click to read more news on the zbot botnet and how it is mimicking the Verified by screens.

http://www.sans.org/newsletters/newsbites/newsbites.php?vol=12&issue=56#sID301

Rogers – where is the front page link to the solution I need?  This did not affect anyone else?

Rogers – where is the email with the link to the fix I need? I have made phone calls…

Rogers where is the phone call and or voice mail telling me what to click to fix this? ou said someone would get back to me.

Apple where is my Bell or Telus SIM (Telus plan looks like it suxs, I’ll take Bell please). Consider sending one out to all iPad owners proactively and thus encourage a competitive mobile data market in Canada.

Rogers please refund me all the missed days – still missing… and credit me a good chunk if I am going to stick around.

Bell, I am probably asking Rogers to get out of my iPad and I’d like to invite you in.  Call me.

UPDATE: July 8th – no 3G data yet.  Was given a ticket number for the affected users.  I assumed they’d put me on a list of iPads to fix when I called them on June 30th… but calling again on July 6th(?) got me on the list (again?).  They are keeping a list – are you on the list?

UPDATE: July 12th – no 3G data yet.  The main ticket number provided to me was PT00016046 if anyone has any ideas on how to move this along – that’d be nice.

UPDATE: July 17th – OK I woke up today and 3G is now working on my iPad.  How’d that magic happen?  Not sure.  A re-boot helped it sync time properly (was a few minutes off).  Now – I have 13 days remaining on my 30 days with zero ability to use data for those days gone by – there has to be something that will just magically fix that too?  Ready and waiting for the clock to be reset.  It is not my idea of fun to hang out on a support line.  Nor is it my idea of fun to be called and told to call support (and maybe later in the day to avoid the wait time).  As much as I use rogers (three accounts) I am not wishing this experience on others.  Currently the display on the “cellular data” link says it expires on 07/30/10.  I hope this date moves – I dread calling yet again, but perhaps I may, just to voice the concept that our agreement has not been met (me data, you money).

Apple may have in fact sold a competing product to the iPhone. For those of us that find the size ok to have with us all the time why would an iPhone be required? A simple voice only phone will now probably suffice. I guess it all comes down to how do you want to balance your freedom. By freedom I mean, to which piper will you pay for voice and data plans. iPad is another choice. It’s 3G appears not to be locked to a provider offering even more choice. In fact fostering actual competition once the different vendors see the need to acquire these new customers with unlocked devices. Not free but a new unlocked freedom may bring a breath of fresh air to the Canadian wireless market if nothing else.

I’ll be looking for a pay as you go SIM on a USA plan when I next visit the states. To prove this device is 1) not locked and 2) I do indeed have this new freedom. In fact over the next few months I’ll try to have a month to month plan with Rogers, Telus and Bell and thus exercise my new freedom. At the very least I plan to watch how the plans settle in. Once they all become contracts for longer periods and start to look like current cell contracts, then I’ll give up my hope for freedom. Here’s to that never happening and a real competitive landscape forming instead.

I do like the iPad 3G in Canada. I have high hopes for it to make a difference in how people work and play. It will make a difference in mine, the month to month data plan already has.

Now with an open hypervisor in Chrome OS, clearly others should be able to take a run at super scale – I mean there are still aliens out there to be found, genomes to be processed. Won’t this all just be fun!

Just saying – RSR – Reality Show Rage is back. They are about to vote off the last American Idol. This will be fun. At least RSR is not yet a crime. However it is a growing problem we should all take a little more seriously than we do. This post may imply RSR is somewhat of a joke. It is not. There should be a Wikipedia page on it by now, but we all just ignore it, pretend it does not exist. How many items will be thrown across the room tonight by those engrossed in a trivial staged and persistent “reality show”. Millions of potentially intelligent, yet brain washed TV viewers (who also watch Nancy Grace, OMG) are about to explode tonight with the final RSR fireworks.

Support RSR research – vote with your money and buy the shirt – when you have it on NEXT TIME – your vote will count and your Idol will WIN !

(Idol can be replaced with survivor, handyman, biggest loser, amazing racer)