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Ryan Mick

Member Since 05 Jan 2011
Offline Last Active Jul 31 2013 03:35 AM
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Posts I've Made

In Topic: Introducing Netduino Plus 2

02 January 2013 - 06:58 PM

Thanks Steve, I knew I had seen it somewhere. The pin out images should be with the hardware specs, it just helps make it more user friendly. I might have to spend some time and try to extract the data from the assemblies. If the source code is available, that would make it a lot easier to generate.


In Topic: Introducing Netduino Plus 2

02 January 2013 - 04:33 PM

Chris, I could have sworn I had seen an image in the forums of the N+2 with the pin breakouts but I can't seem to find it again. Can we get an image of the the N+2 with the pin functions? Also, it would be nice if there was an online reference of the SecretLabs namespace. It would make it a lot easier to know what objects exist there.


In Topic: Help with 24 bit ADC - LTC2499

01 May 2012 - 03:20 AM

Ok, a little closer I think. I have this wired to a trim pot and when I adjust it I get some unexpected values.

            byte byte0 = buffer[0];
            byte byte1 = buffer[1];
            byte byte2 = buffer[2];
            byte byte3 = buffer[3];

            int i = 0;

            bool sig = false;
            if ((byte0 & 0x20) == 0) {
                sig = true;
            }

            byte0 = (byte)~byte0;
            byte0 &= 0x3F;
            Debug.Print("i is now");
            i = byte0 << 24;

            byte1 = (byte)~byte1;
            i |= byte1 << 16;

            byte2 = (byte)~byte2;
            i |= byte2 << 8;

            byte3 = (byte)~byte3;
            byte3 &= 0xC0;
            i |= byte3 ;

            i = (i >> 6)+1;

            if (sig) {
                i = i * -1;
            }

            lReturn = i;

In Topic: Help with 24 bit ADC - LTC2499

29 April 2012 - 09:00 PM

Ok, I have the ADC and I am able to get some values out of it. I have a constant 1.5v going to channel 0 with a 5v ref voltage. Something about the way I am trying to figure out this 2's complement thing isn't working though. There returned values are:

byte0: 10101000
byte1: 10000100
byte2: 11101110
byte3: 01101101

The last bit of byte0 determines if it is a positive #. According to the datasheet a 1 is positive. The bit to it's right is the msb but not part of the value it is a status bit. The 24 bits following that are the value of the channel, the last 6 bits are discarded. As I have said before, binary manipulation is not my strong point so if someone can see what I am missing I would appreciate any feedback.

byte0 byte1 byte2 byte3
10101000 10000100 11101110 01101101 <--original values
00101000 10000100 11101110 01000000 <--modified values

            Int32 lReturn = 0;

            //Is this a positive #
            bool sig = false;
            if ((buffer[0] & 0x20) == 0) {
                sig = true;
            }

            //Clear bits 31 and 30
            buffer[0] &= 0x1F;
            lReturn |= buffer[0];

            lReturn <<= 8;

            lReturn |= buffer[1];
            lReturn <<= 8;

            lReturn |= buffer[2];
            lReturn <<= 8;

            //Clear bits 5-0
            buffer[3] &= 0xC0;
            lReturn |= buffer[3];

            //2's compliment so flip the bits
            lReturn = ~lReturn;
            //Add 1
            lReturn += 0x01;

In Topic: Help with 24 bit ADC - LTC2499

13 April 2012 - 09:49 PM

Thanks Geancario2, I will look at the link. But remember the value is being received as 4 individual bytes, so it has to be pieced together first. I just received the chips today, now I need to assemble them and look at the values under a known analog value to see the resulting bits.

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