[RoadTest] "Freescale RD3803MMA7660FC Review - Serial Communication"

Where can you find more information about this?

I can only see the i2c specs for the chip itself but no further serial specs for the devkit itself.

Do you know which mode is initialized with what you found?

Ok ok I'll dig it up again! :-)

http://cache.freescale.com/files/sensors/doc/app_note/AN3945.pdf?fsrch=1

Or just go the the freescale site and search for:

RD3803MMA7660FCRD3803MMA7660FC protocol

Thanks a plenty

Can't believe they did not attach this document to the RD3803MMA7660FCRD3803MMA7660FC product itself on the website, other application notes can be found but not this one.

Elias

After a quick look it seems that

is actually the handshake response which you would get if you send 0x20; 0x68; 0x0D; so that should not be required.

0x20; 0x73; 0x31; 0x41; 0x41; 0x0D

changes device mode to 1 (low power 4sps) although I'm not sure what are the two A's for

0x20; 0x62; 0x37; 0x41; 0x41; 0x0D

is start data logging with 1.2s timer interval (setting 7) , again not sure about the two A's they are not be required

so if you want to start getting samples you can enter 20 73 31 0D and then 20 62 37 0D or in ASCII <space>s1<CR> and then <space>b7<CR>

with 120sps I would only get samples when moving the device, low medium and scope settings work normally

edit:

"Command sent from S08 to PC
Repeatedly sent when timer interval has elapsed, until stop timer command is sent.
Byte 0-9 :-binary data from Device Register
(0x00 – 0x07) and (0x1A – 0x1C)"

this btw is not completely true as all received messages have the format of <space>CxxxxxAA<CR> where the x's are the the actual data so I'm not sure what is the complete output format

Hello All,

When I wrote the review i haven´t still visit the freescale page. From what I have read from other members review and from my personal opinion, I agree that the I2C board is a good option for develop accelerometer projects, but the uC board is a waste of mony.

Even with the serial protocol freescale implemented on the uC you still have lot's of limitations if you want to develop your own computer application.

Currently I have been using some microchip development boards and they are mutch better for development, because they give everithing you need. For example the pic24F development tool has a programmer on the own board which allows the user to create its own board application.

Hello all,

You'll find in attachement, a .net projet (compiles with VS2005 or Sharpdevelop) consisting of a library(reversed from freescale software) implementing the protocol communication with eval board and a demo program that autodetects port used by the board and registers to a callback outputing register values( refer to datasheet for decoding register values).

Next step is to interface the library with a 3D game.

Best regards

Hi Amine,

I have not tried your code as I have no compiler for it but when browsing through I noticed:

public string setConnection(string port, string handshakeID)
        {
            Exception exception;
            SCIPort = new SerialPort();
            try
            {
                SCIPort.PortName = port;
                SCIPort.BaudRate = 0x9600;
                SCIPort.DataBits = 8;
                SCIPort.Parity = Parity.None;
                SCIPort.StopBits = StopBits.One;
                SCIPort.NewLine = "AA\r";
            }

while in the documentation the rate is 38400, do you get good values with your code?

Hi elias,

The baud rate is written in hexadecimal fomat, so 0x9600 in hexa equals 38400 in decimal.

to compile the code, you can use the open source sharpdevelop ide with the .net framework from microsoft.

BR.

Hi Amine,

That explains it

I downloaded sharpdevelop indeed but as I have a 64bit OS I got errors.

Elias